starting problems

[joeko23]

Hey guys I have a 67 camaro with a 427 big block demon carb with no choke and msd 6al ignition. When the car is cold (haven't started for a day or so) I pump the gas peddle 3 times and it fires right up. However once the engine is up to temp its sometimes really hard to start. I found if I pump the gas like when cold starting its then impossible to start. So now when I try to start with the engine already warm I don't pump the gas. The engine usually starts after a few cranks this way but sometimes it doesn't and I crank the motor untill basically the battery dies (this happened yesterday so I jumped it with my other car, cranked for another 15 minutes or so, then I decided to take off the air filter, cranked again and it fired right up, might just have been a coincidence. Anyway the engine does not overheat it was about 170 yesterday when I was trying to start it. Any advice or what could be wrong? Once started the engine runs perfectly. Thanks guys

[DButler]

When the engine warms up it tends to get richer. This is the reason you adjust your carb once the car reaches normal engine temps.

[joeko23]

DButler thanks for your reply, when the engine is warm the engine runs great and the carb seems to be adjusted correctly for normal temps. Any other thoughts?

[Shaker455]

Warm the car up and take note of your front & rear float level while idlng.

Before you do your restart after operating look in the sight glasses and see where the float level is.

It's possible the bowls are leaking down either inside the carb or outside onto your intake.

Plus throttle blade position should be even front & rear so you'll need to take the carb off and flip it over to check blade position.

Mix screws should also be even in all 4-corners.

How many turns out are you?

Where's your initinal & total timming at?

[joeko23]

Shaker thanks for your reply. I will check the levels. When I do the restart how long should I wait? If I turn the car off then try to start it will start immediately. It has to sit for a few minutes then its sometimes hard to start.

As far as taking the carb off and messing with the settings I'm kind of scared to do that then I won't even be able start it at all. I guess ill try to take it.to a shop. Thanks again for.your reply.

[anthonys 69]

You might want to put a fiber spacer between the carb and the intake. When the engine is worm it might be boiling the fuel in the carb and dumping the fuel onto the throttle plates giving it way too much fuel and if you pump the throttle that will make it worse.

[anthonys 69]

A simple test you can try to see if the carb is loading up is drive the car get it good and hot turn it off weight enough time that the car would be hard to start. Get in the car put the gas peddle to the floor and hold it down don’t pump it. This will give the engine only one squirt of fuel and holding the throttle open will allow a lot of air in the motor as you start the motor. Start the engine. It should start easer with the throttle held open. Once the engine has started REMOVE FOOT from throttle and see if the car idles like it should. Good luck.

[joeko23]

Anthony I will try the full throttle test. I already have a spacer between the intake and carb I think its like 1/2 inch but its metal not fiber. I have a feeling that you might be right about the gas boiling because when I took the air filter off and sqiirted fuel it immediately steamed when it hit the carb. So you think if I switch the 1/2 inch apace to fiber it will resolve the problem?

[joeko23]

Hey guys so first I have a correction, there is no spacer between intake and carb (it's a tall deck intake). Secondly, I got the car nice and hot and while idling took note of the fuel levels in the carb bowls. I let it sit for about 15 mins and then looked again, looked the same. Then I tried to start and it did not start, I tried the full throttle test and that didn't work as well. Basically I cranked on it for close to an hour until it finally started. Does the bowl levels in the carb have to be the same front and rear? On mine the front bowl is about 3/4, while the rear is about 1/4 full up the sight glass. Any suggestions guys? Also any suggestions on local tuning shop in Marlboro, NJ? Thanks!

[joeko23]

Just had a thought, the motor is pretty newly rebuilt (has a little over 800 miles on it since rebuild). When I bough the car, the motor had 200 miles on it, is it possible that with now the motor being closer to breaking in, need some minor tuning to start properly again?

[anthonys 69]

Engine need air, Fuel, spark to run. Too much or not enough of one and it wont run. You hit the gas peddle and fuel squirts in so that’s covered you’ve held the throttle open giving the engine air. What’s your initial ignition timing. Are you sure your getting spark when hot. After engine is hot and you’ve cranked on the motor and it wont start can you take a plug out and see if it wet with gas.
Do you have good engine and body grounds. Are you getting good voltage at ignition coil when hot, low voltage small spark.

Float level should be close to the same but I don’t think that’s your problem.