Hard to start when hot

[Rudolph]

Hello, I have been having hot start problems, seems to do it more when the weather is very hot, engine is a 1938 24 stud, has a bob drake rebuild kit in the fuel pump, I re kitted the carb not so long ago, it has a Pertronic ignition and corresponding coil, I had the same problem when I had the points in the distributor, the engine needs to be cranked over for a wile before it will fire but I found holding the throttle open it will fire up fairly quickly but it will want to die unless I keep the revs up but after a few seconds its fine, I took the top off the carb a few times and its always got a good amount of fuel in the carb bowl and there is no black smoke and its very economical, has a really good spark, its almost like its some kind of vapor lock, or is this just worn engine stuff? it docent use any oil but smokes out the breather, engine is in a 27 RPU with no bonnet temperature never goes over 170 in heavy traffic.

[grumppyoldman]

You didn't mention if it set for a while, that it would start right up. I was having that problem with my 41 and after I cleaned the connections on the Ballast resistor, no more problems. The resistor is under the dash above the steering column, on a fuse block. May be your problem also. Al

[Tinker]

It's hard to check ignition under idle. Try a condenser. I've had decent luck with ih200 from napa, buy a few. Not every is good out the box. There are other options also. Then maybe get a skip coil. Not a bad idea anyway.

[Angledrive]

I believe your carbs are dripping fuel into the intake when engine is off. By opening the throttle you are introducing more air and it is leaning the mixture so it ignites quicker.

[Tinker]

What kind of vacuum are you reading? Set carbs to vacuum.

[tubman]

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To expand on the above from "Angledrive", if you have a 94 model carb, the power valve may be leaking. To check this out, remove the carburetor top after it has been run. The fuel level should be high in the bowl. Put something (I use aluminum foil) over the top of the bowl and leave the top off overnight. Check the fuel level the next morning. If it is down substantially, you have a leaking power valve.

If you find this is the problem, you should replace the power valve. If you do, make sure you get the correct power valve. The power valves for the late model Holley 4 BBL's look almost identical to 94 power valves and will even screw into a 94. However, the seating of the power valve to the body is different and the later power valves will leak in the early carbs. If you get one from your FLAPS or the usual suspects (Summit or Jeg's) they will almost invariably be the wrong ones. Get them from Daytona Parts or someone similar. If you want to be sure. get one (or maybe even a complete rebuild) from "Charlie ny" on this board. You won't be sorry.

[Tinker]

Go to charlie or get some strombergs. Less to worry about.

[Rudolph]

yes ItÂ’s a 94 carb, I took the top off the carb 2 days after and it was still had a good amount of fuel, I have an electronic ignition, it has an internal ballist resistor in the coil,

I removed the plugs immediately after it wouldnÂ’t start and they were dry like it was getting no fuel.

I have never experienced vapor lock, is it creating a gas bubble in between the tank and pump or in the pump?

Because there is no big puff of black smoke when it starts, I guess I should spray some starter fluid into it next time it wonÂ’t go?

[Tinker]

If the bowls are full. It's getting gas supply i'd suspect. PV are designed to open under lower vacuum. It's not vapor lock I'd guess or never experienced.


Bubbles at the pump might be a air leak to the tank. So many things could be wrong really. If you have a full bowl you will have access to fuel. Might be a bad plunger. So much could go wrong.

Get some expert on the carb maybe. Some times some of the electronic stuff don't jive, but you said its the same points too.


I leave my cars sitting over winter 4 months and a few pumps and a choke pull they always start when gas hits the carb. Call charlie on the 94.

[deuce_roadster]

If there is fuel in the carb when it won't start it is either flooded or other reason. When you say it has a "good amount" can you be specific and measure down from the top edge of the bowl?. If fuel is not overflowing into the engine from the heat expanding it or too high of a float level, and it isn't flooded, then I would suspect a bad or loose connection on something in the ignition system, (primary wires, resistor, switch contact on steering column). You say good strong spark, is this during the time when it won't start? What is the compression like on the engine? If you have spark and not excessive gas it should run. As mentioned above, having the throttle wide open (like you do when flooded) helps I think that is a big clue. I once had a barely loose connection between the condenser and the distributor (crab) on a car act intermittently like that.

[Tinker]

It was mid year chandler-groves introduced 1938 the holley 94. Before that it was strombergs. So you okay.

[Rudolph]

On the wires from the ignition pick up to the coil are 2 bullet connectors, I will solder them together in case it’s those connections but I am pretty sure it’s fuel related as it did it with a 100% different ignition system,

It’s like it’s only running on the excellrator pump fuel when it 1st fires up

A lot of time time it will start as soon as you touch the starter, it will cold start pretty well to

[Tinker]

Cold start with a good volt meter you can learn a lot. Run it hot and test with a volt meter. But you have a electronic ignition. Not great advice. Shouldn't have a ballest between the perm and the coil wire to my understanding.

[Rudolph]

Originally Posted by Tinker

Cold start with a good volt meter you can learn a lot. Run it hot and test with a volt meter. But you have a electronic ignition. Not great advice. Shouldn't have a ballest between the perm and the coil wire to my understanding.

Coil has an internal ballest, I tried running another one before it aswell but had no spark

[Tinker]

Not sure you can run a ballast on electronic ignition. But I know nothing about that. Have fun!

[FlatheadTed]

Is the coil the same one that was used with the points ,did you check the spark when the engine was hot and failed to start ,

[Mart]

I agree with the post above re fuel dripping into the manifold.

That or any other of the reasons why a 94 wants to run rich.

I list them out in post no.4 in this thread.

https://fordbarn.com/forum/showthread.php?p=948285

There may be other reasons but all these have been experienced personally by me.

Mart.

[Rudolph]

As I sed befor every part in the ignition system has been changed when going to electronic and it still has the same problem, it dosnt allways do it.

I had a read of that other thread about how when you wind the mixture screws in the engine should start to die, mine will do that, main jets are tight.

I don’t even know if this carb is from a flathead?

[Rudolph]

Funny thing is it dosnt smell like fuel and the plugs are dry and there is no black smoke or any indication of flooding when it starts, it’s like it’s getting no fuel

[Old Redneck]

Check the firing order to make sure they are correct. I bought a 38 ford and drove it home and on the way home the car kept lousing power. I pulled over and the car did not want to turn over. I got a ride home to get my trailer and when I got back the car started right up. so my wife drove the car home and when we got home car did not want to turn over. [Problem was two spark plug wires were cross. I use a screwdriver to find the problem grounding out each cylinder out and two would not die down cross them and that worked. This was my problem then. Would check out?