vettecrazed1

I have trouble starting my car after running it a while and then letting it set for 15 mins or more. I think my timing is off do I need to retard or advance and what is it supposed to be. (66 427/390 )also smells like unburned fuel at times. But on cold start it cranks right up to a fast idle. Also after running awhile you can turn it off and immediately crank it and it starts up.

piper

I had a 67/427/390 and it was 8* BTDC

rowingone

Sounds like fuel percolation to me . . had the same problem with mine . . .you can add an insulating gasket between the carb and intake or remove the intake manifold and block the exhaust ports to the intake manifold. The clue is that if its hot and you turn it off and restart right away its fine . . but leave it for 15 minutes and its hard to start . . . the insulating gasket works but I didnt have the hood clearance for it. About timing . . . well there is a bunch on this forum from Lars that is exactly what you need.

capevettes

It can also be a weak battery or poor ground at the starter.

aaronz28

yep... fuel perc problem... its a nightmare with FI cars.

anyway, with a carb, you can insulate by using a 1/2 inch spacer and that will solve most of the issue..

if it was your timining... your motor would have a stutter ... sort of like the starter was going bad....

there are a few different types of spacers, but you don't want metal or aluminum as they transfer heat less effectively than the wood or other facny plastic types.

if you can get a 1/2 or 3/4 spacer in there, it will solve the problem an quite possible give you a little more response from your motor.

thanks

aaron

aaronz28

just so you are aware of what is happening..

the oil companies keep dropping the boiling point of pump gas in an attempt to keep manufacturing and product costs down...

modern cars aren't affected by this so there isn't a problem...

as your motor sits after it is hot, the risidual heat rises and boils the fuel out of the carburetor and floods you engine.

if you hold the pedal to the floor.. when restarting, that is your best bet to get it to fire up.

Good luck

aaron

knight37128

I had the same problem this summer. It finally got bad enough that when you turned the key off it would catch and run (most of the time).

The problem was the armature in the starter was going bad. Heat would make starting hard, but no problem when cool. If this sounds like what you are going through get the starter rebuilt.

May or may not be your problem but timing doesn't just go bad over night (unless you have gremlins ).

Sky65

Pay particular attention to post 10. Lars is "The man!"
http://forums.corvetteforum.com/show....php?t=1099286

Racer-rt

You can isolate the problem by removing the coil wire when the problem occurs. If the engine cranks fast again the trouble is timing. If it cranks slow/sluggish/strains to crank even without spark-the trouble is with your cranking system. Not uncommon for a big block starter with some wear on the shaft bushings to expand/swell the armature enough to begin to make contact with the magnets inside the case and partially short out.
If it is timing it's too much advance, if not then dead cell or bad starter.
My .02

rongold

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You're not giving us enough info. After a hot soak, does it not crank, or does it crank, but not start ??? Be more specific.

JohnZ

Nope - The formulations continue to change in order to meet EPA Reid Vapor Pressure requirements; EPA has mandated 26 different evaporative formulations, depending on where the fuel is sold, further complicated by the congressional mandate for replacing oxygenates with ethanol (not to be confused with E85).

vettecrazed1

The engine will crank normally afetr running and then setting for 15 mins. but just take a while to start it is definitely not my starter. acts like it is flooded.

B

Joel 67

John is right right about Reid Vapor Pressure, though to be precise ethanol is considered an oxygenate and there is no movement to phase out oxygentates. Mainly ethanol is being used to replace MTBE, which has a tendency to leach into the ground surrounding storage tanks.

427-390

Start with the TIMING first! If your timing is not dialed in properly, you will experience problems like this. Read up on Lars timing paper or Barry K's sticky in the C3 section. 90% of carb problems are really timing problems.

Cheers

mrg

Boy, my experience from a couple of days ago fit just this scenario! .. After reading through lars' timing tutorial thread that he posted just after the Seattle area TFBWT it was time to do a timing curve check.

Trying out different advance weight springs and experimenting around was interesting. After all was said and done and timing buttoned up the car was backed into the garage.

The next day - no start? .. Everything was working fine the day before? .. All the usual supects were checked and gone through. Still, nada? .. I wondered how the timing could 'go bad' from one day to the next? ..

After working the throttle linkage again, this time with reading glasses on, I could see that no fuel was coming out of the squirters? . Couldn't be out of gas? .. . .A sneaking suspicion says fill up the fuel bowl. She fires right up! .. Out of gas, it was! ..

That's whatcha' get when 'old guy' disease (sight, memory, hearing) sets in and messes with stuff . . . Well, some of us, anyway .. ..

That's my gremlin story for today! ..

Colovette

IF the fuel is vaporizing, try mixing one quart of diesel in with a full tank of gas. l've done this with both of my stock big blocks and have found that the hard starting when hot and the raw fuel smell in the garage after shutdown have disappeared. I'm not certain how much diesel one could mix, I just started with a quart and that seemed to be all I needed.