Hard starting after engine is warm

I'm having trouble with my engine starting after I run it to operating temperature and then let it sit for longer than 10 minutes. If I try to crank it within 10 minutes it starts fine . I was wondering if a phenolic spacer may help or if I need to go into it deeper. I also read somewhere the the float level being to high could cause this. Any advise or suggestions greatly appreciated.. It is a fuel issue because after it starts after sitting a while I get really rich exhaust fumes and smoke.

 

If you are running the Rochester 2g series carb it has a power valve in the bottom of the float bowl. There is a power valve piston assy (spring loaded) that holds the power valve closed until venturi vacuum (throttle open) pulls up the piston assy allowing more fuel into the intake. If this piston assy is stuck in the "UP" position (power valve open) then the fuel bowl will drain into the intake until the fuel bowl is empty. This will also occur if the power valve is defective.

 

Thanks for the response Walt. Gives me something to think about. I don't think the whole fuel bowl is draining. If I don't crank it after I warm it up and let it cool back off it cranks up in about 1 revolution like fuel is still on the bowl.

 

OK i just went out to the shop where I have a spare stripped fuel bowl and filled the fuel bowl about half way and let it set. After about 30 minutes I checked the level and the fuel had not dropped very much so I gave you wrong info. I remember doing this test on another one a couple a years ago and it went bone dry so the only thing I can figure was it had a crack in the bowl assy! Sorry about the bad info. Now I have to find that bad bowl.

 

Last time i had a problem like this I cleaned the carburetor, checked filters... it was dirty, I cleaned and since this time the engine works perfectly.
Not to say that it is worse than this but it must be well cleaned. Then you look for other solutions unfortunately.

 

Alright, ordered a new (rebuilt 2g). Old on is #7027082, new is 7027089. Swapped them out, seems to run better but is really rich. Pulled the main jets out of the old one and they or .051. I'm not sure could some one tell me if jet size has anything to do with idle mixture? I don't want to pull the top off of this new carburetor to check jets if they aren't in the equation on idle. thanks for any input

 

Did you adjust the meter screws.

I don't know much about carbs but that's where I would start.

 

Yes, I have them around 1.5 turns out. anything lower than that and it won't idle

 

Main jets for production are .051" high altitude (over 5000ft) are .049" and over 10,000ft are .047".