Thread: 307 olds stalls the warmer it gets

Tweet

I have a 307 olds in my truck was running great the one day just stared stalling seems to run good when it cold but when it warms up it wants to stall or idle so low it trys to stall but when i shoot the gas to it it comes alives and fries the tires

Is the choke hanging up and still partially closed when the engine warms up?

Or does it have an idle solenoid that's failed? Look at your carburetor linkage when it's cold to see what part of the linkage is keeping the throttle position in place at idle, and then where the linkage falls back to when warm. Sounds like something changed in/on your carburetor, or you might have a vacuum hose that's off? Welcome to CHR, by the way! Glad to have you here.

THANKS. the choke seems to be working just fine. a lil leak at the bottom of the fuel bole.

What kind of carb? Check the simple things first - vacuum lines, idle adjustment screw in place, all linkage in the right relationship, etc. You didn't run out of gas recently did you? I filled a carb with sediment crap many years ago and it wouldn't idle at all but still ran OK at WOT or even in heavy mid-range. Also, what about your fuel pump? If it's failing it could starve the carb at idle, but then pick up some at higher rpm's? Grasping at straws here....

It a 750 holley just tore it apart everything was clean put it back together will run but rough played the idle fuel mixture screws no change stated pulling plugs they look burnt seemed like it started this after they switched to winter gas

could the timing chain had jumped a tooth. i took it for a drive plenty of power drove perfect. went back out would barely run until tromped it.

Originally Posted by RATTROD400

could the timing chain had jumped a tooth. i took it for a drive plenty of power drove perfect. went back out would barely run until tromped it.

It's possible if it's a very high mileage engine with a stretched, worn out chain. That's easy to check, as your timing will have shifted relative to the TDC mark on the Dampner. Have you checked your timing with a good light? If the distributor hold down was not tight or worked loose it could also be simply the distributor moved vs jumping the timing chain. Did you have any unusual "event" on that last good run, like a backfire under acceleration?
You mention the plugs "...look burnt." Did you change them?

I cleaned them yes yes there was something not a backfire though when i stopped at the store was only ther for a min came out went to start back and it cranked over slow and hard first time its ever done that just seems to be adding up to that. Thats why i thought timing chain

I'd check the timing to rule that out, or to ID the problem in a couple of minutes. I'd also invest in a good set of plugs, too, if they looked suspect. How many miles are on this engine? Before you got to the store and experienced the hard cranking, did you experience anything else while on the road?

I dont experience anything else i pulled the breather off the valve cover it was clogged put another one on it helped a lil just have to keep to giving it gas

What type of fuel filter are you running? Have you checked it for crud? If you screw the idle screws on the carb all the way in, one at a time, what happens to the RPM?

Originally Posted by RATTROD400

It a 750 holley just tore it apart everything was clean put it back together will run but rough played the idle fuel mixture screws no change stated pulling plugs they look burnt seemed like it started this after they switched to winter gas

Are you sure the idle screw didn't back out?? It happens! Also, if the fuel/air mixture screws don't make any change, there is a problem with the carb!

Its a cheapy see threw i took it off and blew threw it and it free flowed. Im gonna go try and readjust the fuel mixture screws again

The timing was off was on the retarded side advanced it runs smoother but seems to have less power. Still wants to stall when coming to a stop