So i finally got my car on the road after 2 1/2 years, fresh motor and tranny. The car starts right up when cold, but then when it warms up, it hesitates to start. The temperature in the motor is between 200 - 220 max, but i noticed last night even at 190 degrees it did the same thing. The engine will crank, and eventually fire, after a couple of tries. The car has a Pertronix ignitor II and a MSD coil. Again, it only does it when it's warm. Any ideas of what this could be? Thanks for your help.
The heat is vaporizeing the fuel in the float bowls...This vapor ends up in your intake tract, giving you a rich condition making it hard to start your car. Try cracking the throttle open when you do a hot start to get some fresh air in the engine. put a phenolic spacer between the carb/intake to minimize heat transfer.
Thanks, that makes sense. I do have a spacer, and since i have a 351W the carb sits too high almost touching the hood, hence making it hard for the carb to breath. I may have to take out the vents on the hood to allow some cold air. Thanks again, i'll give it a try.
Did you ever get that situation worked out? I have a 72 Comet I just bought and I've had the same issue. It seems to only have a hard time starting if it's been sitting out in the sun. I can run it, drive it around, etc., turn it off, and it will still start up fine, so I'm thinking it's got to be the fuel evaporating when the engine compartment gets hot without any ventilation. Let me know what you ended up doing, and I'll try the same thing. Was also thinking of putting in a hood blanket. I'm new to the car scene tho and chose the comet with a straight six 250, was told it was a good engine for learning. Thanks!
I was having a similar problem but mine was being caused by my choke letting the choke plate close, even when the temps were very warm and the plate should have been open. It was giving me a rich condition, on top of the fuel boiling due to the heat from the intake manifold transferring up thru the carb. Next time when you think you'll have a problem, take your air cleaner off and look at the choke plate to see if it's closed. If it's really warm under the hood, it should be at least partially open. If not, it's going to cause it carb to give you a rich condition and make it hard to start. Someone please correct me if I'm wrong here.
Hi there, the problem stopped when i removed the carb spacer. I still have the hood vents opened (grabber hood) to allow more ventilation.
I don't have a carb spacer, but was thinking about getting one. I suppose now I'll wait till I get this problem resolved. The temp here has cooled a bit, so I haven't been having the problem. Time and hotter weather will yell tho! Thank all of you for the help.
I misunderstood your first question. I thought you were having trouble after driving the car and then parking it for several minutes. You may have to adjust your choke a little bit. Let your car sit in the sun so the problem will occur and before starting it, take off the air filter and look down in the carb at your choke plate. Move the throttle linkage open just a bit, and you should see the choke plate move to the closed position. While you're there, open the choke with a finger and move the throttle open and shut a few times. You should see a little stream of fuel squirt down onto the throttle plate when you do this. If either of these conditions don't happen, you will have hard starting! You sometimes will have to readjust your choke for cold and hot weather. Nothing is wrong, it's just some chokes are very sensitive!
I believe you may be right. I've seen it so bad at times when I lived in the SoCal and Texas heat that the fuel would quite literally percolate in the bowls and rise enough to end up dripping out of the boosters too. I also think simple man also has a valid troubleshooting technique as well. For the half a penny that it's worth.. I haven't used chokes on anything high performance related for well more than 20 years now. I usually just saw the damned things off whenever possible these days. More airflow.. and less tuning variable.
lol that's what i've always done..strapped it open or took it right out...no point in messing with it..makes things more difficult than they should be.
