View Full Version : New motor running hot

11-16-2013, 07:16 PM
Hey Gents, I finally fired up my new motor (1967 390). The builder said to start it and run it at 2000 RPM for 20 minutes. I got to about 10 minutes and it reached 230 degree and was very hot, so, I shut it down.
My father-in law said the fan clutch was shot and that it wasn't spinning no where near fast enough. Is that enough to make it get so hot so fast?

Also, I think understand the coolant flow in the engine, however what does the short nozzle between the intake manifold and the pump do?

One more, what is the purpose of running the engine so high for 20 minutes? I thought it was so the hydraulic lifters and rest of the engine get good oil flow. I was told once that if you don't do that you can ruin your cam.

I let it cool down for an hour, drained the water, then added a gallon of anti freeze and ran it again. This time it got up to 220 degrees in 5 minutes so I shut it down again. I wanted to get some anti freeze in the block. It's supposed to get in the low 30's tonight and I didn't want to risk a freeze.

thx, Dave J

11-16-2013, 08:21 PM
Was the cooling system pressurized?
Yes, a declutched fan will make it run hot BUT, the purpose of the clutch is to slow the fan down as rpms go up. High rpms should mean that the car is running down the road.

2,000 rpm should run your car about 40 mph (or more). That is not fast for an engine. At 40, there should be enough wind going through your radiator to cool it without a fan (on these cool days). Sitting stagnant and running the engine in the driveway, I would run a garden hose with light/medium flow over the rad just to pull some of the heat away. That's another reason why I like electric fans; they only run when the coolant gets hot.

BTW, what's your oil pressure at idle, and above 1,500 rpm? I hope you have a small mechanical oil pressure gauge screwed in. - Dave

11-16-2013, 09:51 PM
Yes, the system was under pressure, as a matter of fact the overflow tank developed a small "hiss" leak when it got really hot.

I'm embarrassed to say that I don't have an oil pressure gauge hooked up. I do have a new sensor and the idiot light though. Before starting the motor I turned the oil pump counter clockwise with a drill and 1/4 inch socket through the dizzy hole. After about 5 seconds I could definitely feel it develop pressure and bog down the drill a little as it pumped oil.

I never had overheat problems with the fan (in the summer) on the old engine. However I never ran the engine at 2000 rpm just sitting still before either.
I guess I can start it in the morning when it's 35 degrees outside and just let it idle to see the temp???

Do you think it's OK to just idle it now? Do you think it had enough time and heat for the break in?

Thx Dave

11-16-2013, 10:55 PM
Check your timing - too far retarded and its 'Chernobyll City' under the hood, trust me...

11-17-2013, 01:04 AM
That's good to know Tom, thx!

I was told to get it running for 20 minutes and then let it idle and do the tuning, timing, etc.

Both times when it was over heating I turned it off it sputtered and popped twice out the exhaust, most likely too rich. I'm going to fire it up in the morning and set the timing. Then adjust the idle, let it warm up and do it again step by step. Hopefully it will help.

Time for bed here, (11:00pm) you should go have a pint and some lunch.

regards, Dave J

11-17-2013, 05:05 AM
Dave, you need to know proper start-up and break-in procedures. Check out how Hastings Piston Ring company says to do it:
CLICK HERE (http://www.hastingsmfg.com/ServiceTips/breakin_procedure.htm)

At Ford, we use Hastings (and have for many decades). Notice they want you to load the engine. They didn't say to run your engine fast but you do need to put a load on the engine to properly break-in rings.

They use the start-up procedure to tune the engine, so you can run the car. This is important. Start-up will tell if the engine has any immediate faults that need attention (like oil leaks, funny noises, etc.). We call this, "Hot Testing" the engine. Every single engine at Ford is loaded and tuned in the engine plant, and they all better be good before going to assembly.

At home, we don't have that luxury so you need to run the car.

After your initial break-in, simply run the car like any new car owner would. I would not let it sit running for 20 minutes. The engine needs a variety of speeds to let it settle-in.

Let me repeat, "The object is to apply a load to the engine for short periods of time and in rapid succession soon after engine warm up. This action thrusts the piston rings against the cylinder wall with increased pressure and results in accelerated ring seating."

This procedure will affect your engine for a very long time. Done right, your new overhaul should last at least ten years of hard service. - Dave

11-17-2013, 10:39 AM
Thx Dave!
That's exactly what I had read on several sites. Run it for 20 minutes at 1800-2000. Then take it out and drive it up to 30mph and let off the gas to slow down. Then repeat. Some said to do that for a while and then move up to 50 mph and let it slow down, then back up.

The engine builder is Doug Anderson in Albuquerque. He's a very well respected and established builder in NM. He said I could do it that way too, or I could just run it for 20 minutes as I did and then just drive as normal, just don't go hot rodding it for the first 300 to 500 miles. He said that would be the best way to break in the clutch too. He said that molly rings seat themselves pretty well and it should be fine.

I'm just concerned with how hot it got. I'm going to do as I said and tune it etc and then see if it gets very hot. Then take it for a spin staying close to the house in case it overheats again.
If you remember my other posts it is a bit of a performance build. 390 with a bored 30 over with a 428 crank. A Lunati Cobra jet cam (the builder said he didn't want to go any wilder than that because of our high altitude and my need for vacuum for the power disc brakes). Cobra jet exhaust valves and comp springs in the c4ae-6090g heads. Edelbrock rpm performer intake and 750 carb. FPA headers.

thx a ton, hopefully it's the timing thing that scumdog spoke of.

11-17-2013, 01:23 PM
Hmm, I can only get it to idle if I go about 20 degrees on my timing, and the idle is still around 800 which is too high. I also have to floor it to start it otherwise it just cranks and doesn't fire. When it shuts down it spurts out the carb and backfires.

Could I be a tooth off on the dizzy? Or will a motor even start like that? Once again my lack of car knowledge is letting me down.

While trying all this I ran it for a total of maybe 5 -6 minutes, and it shot up 230 degrees. Is there anyway to tell for sure that your thermostat is opening?

When I first started it yesterday I did so with the radiator cap off. It started gurgling and spitting water out, and then it just flowed out the cap. I thought this was due to air trapped in the motor, and as the air got hotter and boiled it pushed the water back out. But I really don't know.

Any ideas would be greatly appreciated, I'm starting to worry about ruining this new motor.

thx again, Dave J

11-17-2013, 03:55 PM
OK, the latest. I read on the HAMB that if you use the ported vacuum line on the carb it can mess up idling and cause a retard that can cause overheating at idle.

Edelbrock says to use the ported one so that's where I was. As soon as I switched to the full vacuum port it the car started and idles fine. However, I was at about 20 degrees still, sooo I put the timing to 10 or 11 and it almost stalled. Soooo, I turned up the carb idle and it stays running nicely. However, it still gets really hot so I had to shut it down again.

As soon as it cools to 150 again I'll try adjusting the carb idle screws.

Dave J

11-17-2013, 04:40 PM
Started it up with the rad cap open and it gets up to 220 degrees. Tried adjusting the timing but to get it to stay running at 12 degrees before TBC I have to set the idle screw to run at about 1000 rpm.

Took it for a spin and it would cool down to about 210while cruising about 40 mph. So. at least the cooling is working, it's just running hot and I can't get the thing to idle at 700 rpm without stalling.

Scratching my head, time start over.

thx, Dave

11-17-2013, 08:00 PM

Which radiator are you using - the original? - sorry can't remember. I had quite a bit of trouble with my original and after getting a replacement I can see that the flow is many times better on the new one. If you have an IR gun you can check the tubes on the old one and see if any are stopped up.

Do you have a standard fan off one of the old engines you can install temporarily? It will roar going down the road but might help cool at the slower speeds without the clutch.

I've read that new engines run hotter for a time until they are broken in so since it cools down maybe that's all it is. I know what you mean though - don't want to ruin it guessing.

You can definitely be off a tooth on the distributor and it will still run. Had that trouble on mine when I transferred it to the new engine.

Hope you find the trouble quick and get a chance to try that speedo out.


11-17-2013, 09:04 PM
OK, the latest. I read on the HAMB that if you use the ported vacuum line on the carb it can mess up idling and cause a retard that can cause overheating at idle.

Edelbrock says to use the ported one so that's where I was. As soon as I switched to the full vacuum port it the car started and idles fine. However, I was at about 20 degrees still, sooo I put the timing to 10 or 11 and it almost stalled. Soooo, I turned up the carb idle and it stays running nicely. However, it still gets really hot so I had to shut it down again.

As soon as it cools to 150 again I'll try adjusting the carb idle screws.

Dave J

You should set the timing with the vacuum disconnected and plugged and the idle speed around 500 rpm so there's no mechanical advance. If you can't keep it running at that low an idle then something is amiss. 12 degrees is pretty advanced. I would shoot for 8-10. If you are seeing 20 degrees of advance at 1000 rpm with the vacuum connected that is about normal. The distributor picks up about 8 degrees of mechanical advance and about 2 degrees of vacuum advance at 1000 rpm.

I also use the full vacuum port. I find that my car runs cooler and idles smoother that way. The original Ford 4100 carburetor uses full vacuum at idle.


11-17-2013, 10:25 PM
Well I got it sorted out (I think). After it cooled down I added more coolant and it took a bunch, about 5 to 6 quarts. I also set the timing, adjusted the idle, set the timing again, adjusted the idle and idle screws. Then I took it for a good spin, it dropped down to 190 and stayed there! YES

While in forth gear I drove at 35 to 40 then let off the gas and coasted to about 25, did that over and over for about 20 minutes. Got home, re set the timing, the idle, got it down to about 600 rpm. By the way, I had forgotten to disconnect the vacuum advance and plug it! I read several threads that said a new motor will run hot too. Sooo, I had ordered a new clutch fan from Autozone yesterday and will install it even though I think the old one is OK. The old one is from 1967 so it can't hurt to replace it. I think the radiator is OK, especially with the 67 shroud.

I'm beat, spent the last two 3 day weekends installing this motor, trans, etc all by myself. It was monster and I'm beat. Hopefully I can drive it and break it in a little here and there after work for the next couple of weeks - as well as fine tune it here and there.

Thx for the help everyone, hopefully I can break it in nice and easy and have a fine runner next Spring.

Dave J

11-17-2013, 10:28 PM
Glad you got it sorted out. Just make sure you don't add too much coolant. The level should be near the bottom of the overflow tank to allow for expansion. If you put your finger down the fill hole it should just touch the tip of it.


11-18-2013, 02:10 AM
OK, the latest. I read on the HAMB that if you use the ported vacuum line on the carb it can mess up idling and cause a retard that can cause overheating at idle.

Edelbrock says to use the ported one so that's where I was. As soon as I switched to the full vacuum port it the car started and idles fine. However, I was at about 20 degrees still, sooo I put the timing to 10 or 11 and it almost stalled. Soooo, I turned up the carb idle and it stays running nicely. However, it still gets really hot so I had to shut it down again.

As soon as it cools to 150 again I'll try adjusting the carb idle screws.

Dave J

Ignore ported vacuum totally - it has NO place in cars such as this and is a smog-only item, a crutch to lower emmisions.

11-18-2013, 02:36 AM
I'm glad you got it going, too. A gallon and a half is a lot of coolant. No wonder it was overheating. I took for granted, you topped-off the coolant level as SOP. - Dave

11-18-2013, 09:50 AM
Actually, the builder told me to disconnect the heater hose from the core while filling it and allow the water to run out at that point. Otherwise you get too much trapped air. My helper, who knows a lot more than I do about cars, told me just to keep filling it slowly at the over flow tank and it would gradually fill as the bubbles and gurgling stopped rising.

If I was smart (big IF) I would have read the manual and seen that it takes 20 quarts, then measured as I added to know where I was at.

Oh well, live and learn. It reached 230 degrees twice, once as I was running the initial 20 minute 2000rpm break in (that I had to stop at 10 minutes because of the heat) and again when I was trying to set the timing, idle etc.
Hopefully this didn't cause any serious engine harm.

I never heard any bad noise form the lifters etc as I ran it, and it sounds good now. I'll start it and drive it tonight for about 30 minutes when i get off work.

Thx to all, and I really appreciate the help and patience from you guys as I stumble through yet another one.

regards, Dave J

PS: Dave Dare, you should set up a web site and charge for step by step trouble shooting for guys like me. Your knowledge and step by step analytical approach are a great help! thx

11-18-2013, 11:44 AM
The 20 minute run is to break in the aftermarket cam. You do not want to do that under load. Fix your fan clutch. You should also be using an oil high in zinc.

11-18-2013, 01:00 PM
...PS: Dave Dare, you should set up a web site and charge for step by step trouble shooting for guys like me. Your knowledge and step by step analytical approach are a great help! thxHey, don't thank me. I'm simply passing-on information from the Engine Engineers who wrote the Ford Shop Manuals.

Many had Ph.D's in Metallurgy, Mechanical Engineering and a host of Scientific Research disciplines. Ford has Metallurgical Labs, Casting Development, Powdered Metal Research and Testing (for real exotic metal concoctions that cannot be machined), Welding and Metal Fusion, Heat Treat, Electroplating... and the list goes on and on. The casting guys have their own X-ray machine (which is a whole room) to scrutinize engine blocks that they just poured. To just share lunch with these masters was awesome. But, working directly with them was the highlight of my career at Ford.

I agree, everyone really needs to consult the Shop Manual before doing engine work, even if you have different ideas. Read what teams of highly educated and experienced project experts from the day were suggesting. Ford spent big bucks on these guys. Take advantage and use their knowledge. Your engine goes far deeper than what you see.

Can you imagine casting 1,000 blocks per day (plus intake manifolds, crankshafts, camshafts, flywheels rear end housings and carriers, etc.)? How about two thousand heads (plus exhaust manifolds, etc.)? Where does the iron come from and where do you store it? There isn't nearly enough scrap iron to meet the demand. (None of these castings are machined, yet.)

The Rouge had 17 plants with two foundries going every day. Dearborn Iron Foundry was just one, making FE engine castings. Dearborn Engine Plant machined the parts and assembled them for all Ford Cars and Trucks. Simply a massive operation with capacity of nearly 500,000 engines per year. Even when you see it first hand, the numbers are so huge it's hard to realize the big picture.

Here we are, fifty years later, rebuilding a small fraction of those production parts that were engineered and manufactured to run on different fuels and oils. Who would have thought... - Dave

11-18-2013, 02:19 PM
Thx Charlie, the builder added a quart of whatever zinc additive he uses before giving me the motor. I added 4 1/2 quarts to that and primed the motor through the dizzy hole with a 1/4 inch socket as he recommended.

What I've been using and will use on this motor is the Quaker state "Defy" oil. It has ZDDP? It's a zinc additive. Do you know if it is any good?

Dave D, I used to work at the GE factory in Albuquerque. They machined and casted airplane engine parts. The shop was 4 buildings about 1/4 mile long each. The foundry was much smaller. Anyway, the Ford factories you describe sound like they make GE look like a back yard garden compared to all of Kansas.

I do have a retired friend from LANL who has a couple of Phd's, one in metallurgical engineering. But his knowledge is of corrosives and machining plutonium.

thx again!

11-18-2013, 05:02 PM
Henry Ford used profits from his Highland Park (Model T) Plant to build The Rouge in Dearborn. It's 2-1/2 miles square with no telephone poles.

Henry built a catacombs of cement tunnels between each plant and to the Power House. Workers above ground rarely ever see the depth of foresight 'the old man' had. Through these tunnels he ran 13,800 volt primary electric service, steam (for heating each plant), city water, mill water (for cooling spot welding equipment and guns in the Stamping, Frame, Engine and Assembly plants) and Coke Gas (a free by-product from baking coal into coke).

On top of all that, he built his plants and roads. Most plants were designed by Albert Kahn, using high bay cranes and wide bays. Henry spent most of his time in his work shop, close to the Blast Furnaces, Coke Ovens and Iron Foundry. Edsel had his own work shop building there as well (but he rarely used it).

The Iron Foundry and Blast Furnaces constantly gave off 'flyash'. This stuff was caustic. If a little piece got in your eye it would burn like hell. If it rained outside, the flyash would pit the paint on your car in the parking lot across the street. With all the dust and smoke, we used to get acid rain, just over The Rouge, and nowhere else in Dearborn.

BTW, The Rouge employed over 100,000 workers at once. Starting times were staggered between the plants by 18 minutes (three-tenths of an hour). That gave incoming workers a place to park for the next shift.

It's also interesting to know, Dearborn was a closed community. No blacks. Henry started Inkster, MI, just down Michigan Avenue from The Rouge for his black workers as they couldn't find enough housing in Detroit.

Henry never had a driver's license but he was the Wayne County Road Commissioner. Believe me, Henry owned everything and everyone. Henry's cousin, Clyde Ford, was Mayor of Dearborn (and a Ford dealership owner). Every car in The Rouge parking lot was a Ford (or else). - Dave

11-19-2013, 02:35 PM
Interesting stuff Dave, thx for sharing! Last week on the TV show "Fast n Loud" they said Henry Ford dabbled with the idea of a flying car - quite the forward thinker.

I have another question because I read something on CJ cams. My new 410 is bored 30 over so it's really a 416. (That's very close to a 428) It has a CJ cam. It also has CJ exhaust valves and performance springs in the c4ae-6090g heads. Below in green is what I read - the idle speed says, 725 for a CJ. Do you think that is about right for my motor too? I have a manual trans.

Tune-Up Specifications
The 1968 and 1969 models used a single-point distributor, while the 1970 models used a dual-point setup. All points should be set at a .2-inch gap. The dwell angle should be checked with a dwell meter and set to between 30 and 33 degrees. The ignition timing should be set to 6 degrees behind top dead center. The cylinder firing order for the 428 CJ is 1-5-4-2-6-3-7-8. The idle speed should be set to 725 rpm on cars with manual transmission, and to 675 rpm for cars with automatic transmission.
thx, Dave J

11-19-2013, 03:41 PM
The cam is the key to all this. It unleashes untold 'hidden' torque at the expense of two things, high idle (because of duration) and very bad gas mileage (because of duration). Your cam and compression ratio will determine what the exhaust will sound like as well. The longer the duration and higher compression, the louder it gets. Watch your spark plugs for early fouling, depending on your compression ratio.

I don't know which CJ cam you are using. Factory engines weren't as wild as aftermarket offerings because Ford had a warranty on these engines for a year. Idle speeds were around 600 rpm or slightly higher.

Huge valves only help at high rpm (and hurt low rpm). Truck heads have small valves because they do most of their work at low rpm. Stiff springs and shims help stop valve float (and bounce).

If you are building this engine for high rpm service (racing), your CAM should be retarded at the sprockets by about four cam degrees, not your ignition timing. - Dave

11-19-2013, 08:49 PM
Thx Dave, I know next to nothing about cams so I appreciate the help. Here's the one I have. http://www.carshopinc.com/product_info.php/products_id/135616/10331003?gclid=CO6YuN2Z8roCFTBgMgod-FAA5Q
I think it specs the same as an original 428 CJ cam.

My compression is about 10.5 (I have Mercury 410 pistons).

The build sheet also lists "comp springs", "valve shims", "exhaust valves 428 CJ stainless", "molly ring set", "reface and rebuild rockers".
He said that the shims are to do with making all the valves even, or same lift, or something? I'm sure it makes sense to you.

He told me to set the initial timing at 10-12 degrees. He said whatever I do don't go over 38 total. I kind of understand the cam advance, but I thought these numbers might tell you something about the build. I should have wrote more down when I talked to him. I can always call him. He's a Ford guy, and I was told he knows FE's really well. Thus I gave him an idea of what I was looking for and asked his advise.

It's not a race engine, it's more of a street/strip car but I told him I wanted to keep torque and improve HP. I said I want it to be a little rowdy for car shows etc. I also said that mpg's didn't matter because I would be driving this car maybe 500 miles a year. He advised against too much of a cam because of the altitude and vacuum needed for power disc brakes.

He said the 416 will have good torque for low end and the head work would provide a little better rpm range for HP at the high end. He said the intake valves for these heads were real close to the 428 size so we left them the same. And of course they are a 3 angle valve. Sounded good to me.

So I'm guessing about 700 rpm idle? What do think with this limited bit of information?

thx again!

11-20-2013, 01:21 AM
Let's look at a few cam spec's:
LUNATI 10331003
Factory Perf Cam - Ford 352-428FE 304/324
Hydraulic. Lunati's version of the C60Z-B 428 CJ & 360 horsepower camshaft.

Advertised Duration (Int/Exh): 304/324
Gross Valve Lift (Int/Exh): .481/.490
LSA: 114
RPM Range: 3000-6000

It's a Lunati (Brand) flat tappet cam, ground to their equivalent of a Ford CJ cam. This is a racing cam with lobe separation of 114.
The, "Advertised Duration (Int/Exh): 304/324
Gross Valve Lift (Int/Exh): .481/.490"

For my purposes (cruising, street/driver cam), I would stick close to a duration of around 270, but you aren't me and I'm not you.

This cam is hot. So hot, it's really made to burn nitrous oxide. Idle speed is up there because it produces very little hp at low speeds. The spec's say 3-6k rpm. That's your torque range. I like producing torque down around 1,500 rpm or even lower, and I want it to peak around 4,500 rpm, not 6k. But again, that's me.

It's probably good that you have a stick because your engine will need high rpm, simply running around town. It might be a fight with the gas pedal, trying to idle at a light, unless your rpm's are up high enough to overcome the 'lope'. I would call this a perfect cam for use on interstate commutes (but not in rush hour traffic). It certainly produces great torque, especially with large pistons, at high altitude and at high rpms. It would even produce more, closer to sea level. But hey, at altitude, all the cars around you are starved for oxygen as well.

Your compression ratio is very high which requires 93 octane. You will need ZDDP (zinc/phosphorus) oil additive, especially with heavy valve springs.

The alternative is to use a roller cam, which is what modern engine oil is designed for. The problem is, hydraulic roller cam setups are expensive (around $700 to retrofit an FE engine, then you need pushrods ~1/2" shorter). This is what I'm using in Penelope's 390.

All I can say is, HOT, HOT, HOT! I hope you get a good true roller timing chain set for this cam. - Dave

11-20-2013, 10:17 AM
Thx Dave. I do have a good roller timing chain set, and I am using zddp oil. He said I should be OK at 91 octane. Right now the rpm is set to ~ 600. It idles OK when completely warm but I think I'll tinker with it around 675 or 700, but when cold (and 40 degrees outside) I have to ride the gas pedal a little for the first 2 minutes or it dies. He said I should be fine with premium octane (91), but to definitely use a lead additive which I do religiously.

I changed out my primary's and metering rods in my Edel 750 to match our altitude (as recommended by Edelbrock)

I was reading that ethanol enhanced gas is a bad idea for some reason or other? I can't remember, but it said something about gas stations using it in the winter months. Do you know anything about that?

I'll tell you one thing I noticed, the centerforce dual friction clutch really grabs - I'm going to be super slow at breaking this motor and clutch in until at least 500 miles. I'll have to make a point of taking it out on the warmer winter days to put some miles on it so I can have some fun with it come Spring and summer.

thx, Dave J

11-20-2013, 11:16 AM
When I first got my Edelbrock carb I had to tinker quite a bit with the electric choke to get it to run right when cold. Seems that you have to find that sweet spot between fully closed and partly closed along with the correct fast idle rpm. Also did you adjust the mixture screws. It may be running too lean.


11-20-2013, 12:25 PM
I question the Ignition timing. BTC is Before top dead center. These specs are a good starting point. Research tuning with a vacuum guage.

11-20-2013, 04:06 PM
Thx John, I noticed that too. Mine is manual, and as soon as I close it the motor dies in a split second. But if I barely open it it doesn't seem to do much. I'm going to try it this weekend and adjust the choke idle screw too, that seems to be the key. Once I get it where it works best I'll really cinch that cable in place.

Do you guys think I should use an octane booster? It doesn't seem to ping or anything.

Charlie, I have a cheap vacuum gauge, but I don't trust it and I don't know anything about tuning a car with one. I'll check with my father-in-law and see if he has one and knows ho to do it. Other people have said that's the best way to go. I may also upgrade sometime to a Petronix dizzy. They seem to have good info on using the springs to adjust the vacuum advance. Either that or pay my local mechanic to adjust mine.


11-20-2013, 05:27 PM
Manual choke? How are you opening it up. With a cable that runs into the car? That takes me back a few years.

Even the cheapest vacuum gauge will work just fine. For adjusting the mixture screws just turn each one clockwise until the engine starts to miss, then turn counterclockwise until it hits the highest vacuum. Then turn clockwise until it just starts to drop.


11-20-2013, 06:13 PM
Where do I plug in the vacuum gauge John?

Yes, it's a manual with a cable. I'm using an old exhaust valve for the choke know in the dash. Rat style!


11-20-2013, 06:40 PM
Any manifold vacuum source will work. I usually unplug the line to the brake booster and use that if nothing else is available.


11-21-2013, 10:13 AM
Thx, I'll give that a try this weekend if the weather permits. 90% chance of snow tonight!

dave J

03-25-2015, 07:26 PM
[ autolite 4100 has Four Corner Idle circuit if they are clean, and pulling
,the 4100 should should run with front two idle screws screwed softly all
the way in (but run ragged and choppy) (it's working) ..
Put your hand over the idling cab and see if it speeds up OR smoothes out !
IF so ya got vacuum leak somewhere..
also the FE manifolds distribute Fuel better with a carb spacer Or
the factory wedge spacer... the 4100 is a great carb
that can run with the air lid OFF . (get your carter to do that).
try to use the factory advance if you can.