Engine wont start when warm....

[63C20]

So, I have a 1971 307, 2 barrel, automatic, points distributor. When its cold it fires off great no choke needed, which makes me think the floats might be too low since i never need to choke it?

anyways, when its warmed up it cranks over fine so no heat shields needs for the starter or solenoid, but i have to hold the pedal to the floor and dump the carb to re-start. only visible issues Ive seen is the carb seeps at the throttle rod bushings. I have set the points/dwell, timing etc.

flooding? timing?

[b454rat]

Does black smoke or any type of smoke appear once started? Sounds like carb needs adjusting.....

[63C20]

No smoke at all.

[James the III]

Have you manually looked when warm to see if indeed the choke is open.. and not flopping closed..

[cadillac_al]

Back in the day I could never get more than 2 years out of a set of points. In our farm trucks we changed them every year. Just routine maintenance to keep them running good. Old points cause headaches. Sometimes those old coils fail when they get hot too.

[fleetsidelarry]

Originally Posted by 63C20

So, I have a 1971 307, 2 barrel, automatic, points distributor. When its cold it fires off great no choke needed, which makes me think the floats might be too low since i never need to choke it?

anyways, when its warmed up it cranks over fine so no heat shields needs for the starter or solenoid, but i have to hold the pedal to the floor and dump the carb to re-start. only visible issues Ive seen is the carb seeps at the throttle rod bushings. I have set the points/dwell, timing etc.

flooding? timing?

good suggestions from the other guys.

like b454rat says, I think it's time for a carb rebuild. if it was an edelbrock we"d all yell "heat soak" (percolation) I don't recall anybody having posted about that sort of problem with a 2 barrel but I guess it's possible.

it this a recent problem?

my guess, if it's the float it's either set too high (unlikely) or more likely fuel-logged (pin-hole in metal float or soaked plastic (?) float). could be trash in the needle/seat.

easy enough rebuild, but kits are universal, lots of different gaskets for all the models. make sure you pay attention to whether or not the accelerator pump has a ball under it, some models do, some don't.

[cg285]

Originally Posted by 63C20

only visible issues Ive seen is the carb seeps at the throttle rod bushings.

here's a clue. there is supposed to be no fuel at the throttle shaft. if there is it's flooding

[TJ's Chevy]

If you have to put the pedal to the floor it's because the carb is flooding out. By flooring it you are giving the engine a straight lean shot of air which finally vaporizes the fuel so the engine will start. Engines like rich starts...so stone cold it will be fine, but hot...it's flooded. Either the float is to high Or since you mentioned fuel seepage at the throttle shaft....it's time to check that carb out. Good excuse for a 4 barrel now.....People complain up the hill that Edelbrocks have problems....Holley's flood engines out just as bad if not worse under the same conditions.

[johnthegreat508]

Sounds like the carb is super rich, float could be adjusted a little high or could have a little piece of grit in the needle and seat.

[63C20]

Originally Posted by cadillac_al

Back in the day I could never get more than 2 years out of a set of points. In our farm trucks we changed them every year. Just routine maintenance to keep them running good. Old points cause headaches. Sometimes those old coils fail when they get hot too.

i was thinking new points but they look good. could the condenser do that?

[63C20]

Originally Posted by James the III

Have you manually looked when warm to see if indeed the choke is open.. and not flopping closed..

all good

[63C20]

Originally Posted by cadillac_al

Back in the day I could never get more than 2 years out of a set of points. In our farm trucks we changed them every year. Just routine maintenance to keep them running good. Old points cause headaches. Sometimes those old coils fail when they get hot too.

points are perfect and coil tests great

[TJ's Chevy]

Originally Posted by 63C20

points are perfect and coil tests great

Did you check the coil's resistance?

[63C20]

Originally Posted by TJ's Chevy

Did you check the coil's resistance?

i have a coil load tester

[TJ's Chevy]

Originally Posted by 63C20

i have a coil load tester

Those are handy. lol We have one at the shop. If spark is good and you are sure the points are decent, I'd still be looking at fuel. Especially since you mentioned there is some seepage.

[63C20]

and if i hammer the throttle i get 1 solid pop out the carb.

[TJ's Chevy]

Originally Posted by 63C20

and if i hammer the throttle i get 1 solid pop out the carb.

Running lean because of a vacuum leak no doubt. Time to look through that carb.

[storm9c1]

Originally Posted by cg285

here's a clue. there is supposed to be no fuel at the throttle shaft. if there is it's flooding

^^^^ This.

And... since nobody else asked, what is your initial timing set to? I like to make sure timing is straight before blaming the carb. Some of these symptoms could be compounded by retarded timing.

[James the III]

Originally Posted by cg285

here's a clue. there is supposed to be no fuel at the throttle shaft. if there is it's flooding

But is it a leak from a gasket/ float/etc or from fuel boiling out the vent tube..

as this is listed as a warm restart problem.

It is easy to point finger at the carb.. and it maybe.. but...

[63C20]

over flowing, the float was full.

[homemade87]

Originally Posted by James the III

But is it a leak from a gasket/ float/etc or from fuel boiling out the vent tube..

as this is listed as a warm restart problem.

It is easy to point finger at the carb.. and it maybe.. but...

What you may be have happening is when you run the engine and shut it off the fuel line still has pressure . If the needle and seat can not hold that pressure it will bleed by and go into the bowl . When the level gets high enough it will over flow into the venturi and drip right on the butterfly and shaft and into the engine . Thats most likely why you see fuel at the shaft dripping . One way to see if in fact this is happening is when you drive and get the engine to operating temp shut it off and remove the filter and look down the carb . You should see drops of fuel dripping from the venturi . Most of the time there will be a fog in there as well (extra fuel trying to vaporize) . This is flooding the engine and a warm engine does not like that extra fuel . This will create a warm hard start situation .

So remove the filter and see whats going on . Could be just a float needle and seat change is all thats needed .

[Ironangel]

Originally Posted by storm9c1

And... since nobody else asked, what is your initial timing set to? I like to make sure timing is straight before blaming the carb. Some of these symptoms could be compounded by retarded timing.

Good point!...Your carb could probably use a rebuild. The fact that no choke is necessary during a cold start is evident of a rich situation. having to hold the pedal to the floor once warm is another as well as fuel leaking from the gasket that no doubt needs replaced. The 2G's are notoriously rich running carbs which is why (other than middle of the road sized primaries) they get worse mileage than the Quadrajets...Replace the questionable vacuum lines all the way down to the modulator and put a new 1/4" inch gasket under the carb after the rebuild and dont forget to protect the clean carb with a new inline filter. You need to learn how to adjust that choke because a properly adjusted carb will need some choke at start up...

[63C20]

Thank you all for the ideas, i needled through one by one, the float was half full and the valves look crappy. now im fighting with finding the right kit (which i can do on my own) but a float seems impossible since the tag is missing. its a 2G and parts people are ignorant now

[Ironangel]

Originally Posted by 63C20

Thank you all for the ideas, i needled through one by one, the float was half full and the valves look crappy. now im fighting with finding the right kit (which i can do on my own) but a float seems impossible since the tag is missing. its a 2G and parts people are ignorant now

Yup, they're only as smart as them damn computers! Try and find an old mom and pop autoparts store or at least an old man behind the counter. The 2G's had tags but there will be a number stamped on them.

[63C20]

mine has NO stamps lol