DScott

DScott

DScott

Junior Member
Good Morning !

I am a new member and a new Model A owner.

I recently purchased a beautiful '29 coupe, and I am having some engine problems. The engine starts easily and idles well. It runs fine for about 15-20 minutes, and then the power output drops significantly as it warms up.

I went ahead and rebuilt the carb with a kit I purchased from Macs, and the problem still persist. I drove it yesterday, for about 30 minutes, low speed, and then it did the same thing. Backfired once or twice and power was diminuished. I stopped and checked the water lever in the radiator and water was visible in the radiator from the top. There was no water on the engine, so no reason for a a short in the ignition system.

I let it cool a couple of hours and it started and ran just fine. I put in the garage and thought I would try a forum. I am a newbie so I break me in gently.
 
Sounds like vapor locking. Could be other things, but this is the most common cause of these symptoms.

Next time it does this, take with you a gallon of water. Shut off the car, and pour the water on the carb.

If it starts right up and runs good for a while, then it is vapor locking.

If that is the case, then try running the fuel mixture a tad richer and see if the problem gets better.

What was the outside temp. when you were out running the car?

Steve Becker
Berts Model A Center
 
DScott said:
Good Morning !

I am a new member and a new Model A owner.

I recently purchased a beautiful '29 coupe, and I am having some engine problems. The engine starts easily and idles well. It runs fine for about 15-20 minutes, and then the power output drops significantly as it warms up.

I went ahead and rebuilt the carb with a kit I purchased from Macs, and the problem still persist. I drove it yesterday, for about 30 minutes, low speed, and then it did the same thing. Backfired once or twice and power was diminuished. I stopped and checked the water lever in the radiator and water was visible in the radiator from the top. There was no water on the engine, so no reason for a a short in the ignition system.

I let it cool a couple of hours and it started and ran just fine. I put in the garage and thought I would try a forum. I am a newbie so I break me in gently.
Click to expand...

SteveB31 said:
Sounds like vapor locking. Could be other things, but this is the most common cause of these symptoms.

Next time it does this, take with you a gallon of water. Shut off the car, and pour the water on the carb.

If it starts right up and runs good for a while, then it is vapor locking.

If that is the case, then try running the fuel mixture a tad richer and see if the problem gets better.

What was the outside temp. when you were out running the car?

Steve Becker
Berts Model A Center
Click to expand...

The temprature outside was mild mid 70's
 
I agree with Steve that it sounds like fuel boiling. I had the same problem, but solved it by only using good gas with no ethanol. I also use 4 oz. of Marvel Mystery Oil with each 10 gallons.

When an engine starts running bad, or dies, the first thing I do is pull the coil wire and hold it 1/4" from a head nut to check for a hot blue spark while cranking the engine with the key on.
 
Tom Wesenberg said:
I agree with Steve that it sounds like fuel boiling. I had the same problem, but solved it by only using good gas with no ethanol. I also use 4 oz. of Marvel Mystery Oil with each 10 gallons.

When an engine starts running bad, or dies, the first thing I do is pull the coil wire and hold it 1/4" from a head nut to check for a hot blue spark while cranking the engine with the key on.
Click to expand...

Would the condensor only do that when the engine is up to speed ? that goes bad it would backfire whether hot or cold. It only seems to happens after it gets warm, 15-20 minutes low speed.

I like the idea of gas without ethanol, and adding Marvins. I will try that.Thanks to all for helping me out
 
I have never had a coil nor condenser go bad on any car I've ever owned, but I have seen bad condensers and they gave a very weak spark hot or cold. Some have reported that they've seen condensers fail when they get hot, which is very possible. When I see something loose spark when it gets hot, it's usually the coil. I've seen that on old and newer customer cars.
 
Tom Wesenberg said:
I agree with Steve that it sounds like fuel boiling. I had the same problem, but solved it by only using good gas with no ethanol. I also use 4 oz. of Marvel Mystery Oil with each 10 gallons.

When an engine starts running bad, or dies, the first thing I do is pull the coil wire and hold it 1/4" from a head nut to check for a hot blue spark while cranking the engine with the key on.
Click to expand...

Tom, so the wire from the coil to the distributor (? 20k Volts so something like that?)

http://www.modelabasics.com/ignition/ignition still.gif
 
DScott said:
Good Morning !

I am a new member and a new Model A owner.

I recently purchased a beautiful '29 coupe, and I am having some engine problems. The engine starts easily and idles well. It runs fine for about 15-20 minutes, and then the power output drops significantly as it warms up.

I went ahead and rebuilt the carb with a kit I purchased from Macs, and the problem still persist. I drove it yesterday, for about 30 minutes, low speed, and then it did the same thing. Backfired once or twice and power was diminuished. I stopped and checked the water lever in the radiator and water was visible in the radiator from the top. There was no water on the engine, so no reason for a a short in the ignition system.

I let it cool a couple of hours and it started and ran just fine. I put in the garage and thought I would try a forum. I am a newbie so I break me in gently.
Click to expand...

WELCOME :) ! Let's see pictures of you A ! Lots of Questions, but from what you say here....THINK HEAT ! After things get hot, like condenser/coil, sounds like breakdown in elect system. Ensure every electrical connection is clean and firmly secured. Check coil after hot and breakdown starts , as Tom suggests, after eliminating or confirming check/replace condenser if you have a good spare. Good luck
 
By now you've probably already checked and eliminated the gas cap venting, as suggested by Duffy in #5. If not, consider this...

A friend of mine once cut a nice plastic disc from a milk jug to fix his leaky gas cap. Worked great! But guess what... Same symptoms as yours. Backfiring, sputtering, coughing after it ran a while. If the previous owner used a non-venting radiator cap, or "fixed" a leaky gas cap, your engine might starve for gas as a vacuum in the tank builds up. Easy to check.
 
First thing to do is to blow out the fuel line from the carb to the tank and make sure you are getting a solid flow of gas. If you can fill a quart can or jar without the fuel demishing flow then go on to the other suggestions. Bet this works.
 
DScott,
whenever i get a car thats new to me i go through all the basics first to make sure things are up to snuff and safe. to many jump in and go without servicing the rear diff, trans, changing the oil and servicing the cooling system. along with that a fresh tune-up, timing ck is in order along with a short proof condenser. there are different variables that could be installed inside your distributor, such as if someone put in a wireless lower plate, that needs to go. or replaced the fuel line and pushed it to far past the ferruls. its important to know what is installed on your vehicle. shake down the frt end and ck and adjust the brakes. lube all what needs to be lubed. feel free to ask your questions take some pics and post them up here, say of inside the distributor and we can help you on whats good and bad.
take some under hood pics of both sides of the engine bay
 
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I am voting condenser as I have have them fail where the car would sputter and backfire. They would die due to heat, and the 20lbs of cast iron heater manifold that sat right next to it. Welcome to the club, post some pics and where you live. Someone may be close enough to come over and give you a hand.

Mike
 
Mitch//pa said:
DScott,
whenever i get a car thats new to me i go through all the basics first to make sure things are up to snuff and safe. to many jump in and go without servicing the rear diff, trans, changing the oil and servicing the cooling system. along with that a fresh tune-up, timing ck is in order along with a short proof condenser. there are different variables that could be installed inside your distributor, such as if someone put in a wireless lower plate, that needs to go. or replaced the fuel line and pushed it to far past the ferruls. its important to know what is installed on your vehicle. shake down the frt end and ck and adjust the brakes. lube all what needs to be lubed. feel free to ask your questions take some pics and post them up here, say of inside the distributor and we can help you on whats good and bad.
take some under hood pics of both sides of the engine bay
Click to expand...

That's what I did a while back.
 
Thanks for the advice. I know the previous owner and he took very good care of it. I will do as you suggest though. It makes sense to keep an eye on it and stay ahead of issues if possible. By the way, that is a beautiful young lady you have in front of your house !:)
 
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