Hard hot starting.

bigrob · #1 (**permalink**) 03-26-2008, 11:04 AM

I finally got my car on the road & I have found that after she reaches normal operating temps & I stop somewhere, when I restart the car, it cranks for a while & it seems like it may be flooded. It finally does start after maybe 10 seconds. I have a new Holley carb & have it re-jetted for my altitude here in Vegas. I also leaned out the mixture very slightly. I dont think I am starving the carb. It idles fine, is slightly sluggish at lower RPM's but seems fine. Cold starts are OK. I have not checked the timmimg, but I am thinking it should be OK. Anyway any help at this would be awsome!

Thanks!!

J Persons · #2 (**permalink**) 03-26-2008, 11:20 AM

It's probably heat soak into the carb. My car does the same thing in the summer when the air temp is over 100. About the only cure is to isolate the carb from the engine using an insulated spacer, or a turkey pan that seals against the bottom of the hood. Holley sells an aluminum plate and spacer that is probably better than thean insulated spacer by itself, but still probably not as good as a turkey pan.

jhv48 · #3 (**permalink**) 03-26-2008, 11:29 AM

Don't touch the throttle on re-start.

bigrob · #4 (**permalink**) 03-26-2008, 11:30 AM

Quote:

Originally Posted by J Persons

It's probably heat soak into the carb. My car does the same thing in the summer when the air temp is over 100. About the only cure is to isolate the carb from the engine using an insulated spacer, or a turkey pan that seals against the bottom of the hood. Holley sells an aluminum plate and spacer that is probably better than thean insulated spacer by itself, but still probably not as good as a turkey pan.

Thanks for the info. I may have to do the turkey pan. Do you need to remove the carb to istall it? I remember the PO telling me he had a hot starting problem as well, but said it was the coil getting too hot & due to the fact that is was mounted to the motor. He relocated to the fender wall.

Thanks again!

undy · #5 (**permalink**) 03-26-2008, 11:58 AM

If you have a single line fuel system and an electric pump your fuel pressure can creep and over power the regulator and subsequantly your bowl fuel inlet needle valves, did on mine. That can cause the symptons you're describing. If you have a fuel pressure gauge at the carb you can watch it at idle to see what it's doing. If it goes past 8 or 9 psi then you've problems. You can drop your carb bowls levels and see if that makes the situation any better. At least that'll confirm and point you in the right direction. If you have a MSD distributor check the cap too. A poor spark and a rich condition can also be a cause for a hard start too.

Dave

rbray · #6 (**permalink**) 03-26-2008, 12:57 PM

Wow, perfect timing on this topic as I am having the same issue.

On the next hot restart I'm going to turn off my electric fuel pump and not touch the gas at start up.

Thanks for the tips guys

bigrob · #7 (**permalink**) 03-26-2008, 01:36 PM

Quote:

Originally Posted by rbray

Wow, perfect timing on this topic as I am having the same issue.

On the next hot restart I'm going to turn off my electric fuel pump and not touch the gas at start up.

Thanks for the tips guys

I am gonna leave the gas pedal alone. That was the one thing I did not try. I do not have a regulator. My carb requires 5-7 & the carter pump I just put in is at 8. The guys a Holley said a regulator would not be needed. I am also gonna leave the pump off when I crank it over & after she starts, I would put it on. We'll see what happens.

Thanks for the help guys!!

GlynMeek · #8 (**permalink**) 03-26-2008, 02:04 PM

excellent answers for those of us who never even thought to ask but who have EXACTLY the same problem. Foot OFF the gas pedal for me too!!!! Thanks jhv!!!

Excaliber · #9 (**permalink**) 03-26-2008, 02:49 PM

Just recently I've been noticing this problem, hard starting hot. I've found I actually need to pump the throttle once, like it's not getting enough gas until I do. It cranks real good, but takes awhile to fire unless I 'pump it' once. Go figure... It's all about finding out what YOUR specific engine needs are under various conditions. For a cold start, WAIT for the fuel pump to fill up the carbs, then I pump it exactly four times (I don't have a choke) and it fires INSTANTLY. Less than four pumps, it cranks for awhile. Dual carbs, giant ports/heads, could have something to do with needing to 'feed it'.

mr0077 · #10 (**permalink**) 03-26-2008, 03:03 PM

Also, if leaving the foot off the gas (so you don't add fuel with the accelerator pump) at startup doesn't work, try one smooth stroke to wide open throttle and hold it open during the startup...this will let in a little gas and a LOT more air and clear out the over-rich problem quickly...IF it is in fact flooded.

wtm442 · #11 (**permalink**) 03-26-2008, 03:10 PM

I pump the gas pedal twice for a cold start and once for a warm start. I've put 15K miles on it and so far so good.

BigRob - on a warm start, does the starter spin the motor as fast as it does on a cold start? If it is really slow cranking when warm, you might want to take out 1 or 2 degrees of initial timing and put that amount of timing back into the mechanical advance.

bigrob · #12 (**permalink**) 03-26-2008, 03:32 PM

Quote:

Originally Posted by wtm442

I pump the gas pedal twice for a cold start and once for a warm start. I've put 15K miles on it and so far so good.

BigRob - on a warm start, does the starter spin the motor as fast as it does on a cold start? If it is really slow cranking when warm, you might want to take out 1 or 2 degrees of initial timing and put that amount of timing back into the mechanical advance.

I had'nt noticed, but I will check into that as well!

Thanks!

Roscoe · #13 (**permalink**) 03-26-2008, 03:37 PM

Sometimes a start retard on the ignition could solve the problem. Another area is a if you mount the battery in the trunk and run a line that is too thin. You should run 0 or 1 gauge.

Roscoe

PatBuckley · #14 (**permalink**) 03-26-2008, 04:12 PM

I found that if you are using an MSD distributor that the center electrode in the cap will go away resulting in a hard start hot also.

bigrob · #15 (**permalink**) 03-26-2008, 05:05 PM

Quote:

Originally Posted by PatBuckley

I found that if you are using an MSD distributor that the center electrode in the cap will go away resulting in a hard start hot also.

What do you mean when you say it will go away? That is the type I have. I am curious.
Anyway the " no gas pedal & fuel pump off " did'nt work for me. I think the foot to the floor will be best! Not a real big deal, she does start..........eventually

rbray · #16 (**permalink**) 03-26-2008, 05:35 PM

After reading this post I fired up the car from a cold start and let it warm up to operating temperature. After letting it sit for an hour I attempted a restart with the fuel pump off and no touch on the gas pedal. Viola!!!! it fired right up.
Then I shut it down and restarted after pumping the gas pedal a couple of times. It started but it was not smooth.
The moral of the story for me is to keep my foot off the gas on hot restarts.

Thanks again guys