joshtried

So, i have a Holley 750 electric choke on top of a sb 350. the only modifications to the engine are an Edelbrock intake and hooker headers (as far as i can tell anyways). the problem i am having, is when the electric choke heats up, the engine dies... every time right now (around 160-180 engine temp). if i close the choke at the top of the carb, i can get the engine to stay on and idle properly, if i just let it stay open, i have to keep it rev'd to around 4k for it to stay running. i went and bought a new fuel pump, thinking that was the culprit.. but the problem persists. also of note, the car recently started backfiring, ALOT (The plugs were almost all fouled). a quick change of the spark plugs solved that. both of these problems started at the same time... since then, it just wont run right.
your opinions? suggestions?

joshtried

i have recently changed the fuel filter and blown out the filter in the carb as well. i have also tried running more rich and more lean, with neither helping..

gingerbreadman1977

sounds like an answer to this is ...get rid of that choke. its fouling you up. other then that just check your timing with the backfiring.

joshtried

i tried that, and it stalls out if i rev the engine, with idle set at 850-900 (the needle bounces a bit on the brand new tach) though it stalls the same way with the choke on while it is hot. if i rev while choke is cool, it does not stall
i think the backfire was a combo of fouled plugs & poor plug gap. i think the gap was .35 to the now .45 number 5 & 6 were both normal, all the rest were fouled, and smelt like unburned fuel. my timing is set at 10* or 12* right now..

Woodsters

How long since you've rebuilt the carb? It is possible you disturbed some trash while cleaning the fuel filters. It is possible to tune a 750 cfm for a 350 c.i. engine, but it is a bit oversized. Since your engine is basically stock, a 600cfm carb could work. You might notice crisper throttle response and perhaps a slight improvement in fuel economy.

joshtried

carb was bought brand new 1 year ago, no rebuild since then. it did sit for a whopping 2 months. the in carb filter was dirty after changing the filter, but it has been blown out, as this has prevented me from even starting the car before... now its almost the first thing i check, just because its so ridiculously simple.

Timsride

Check Your sight plug if You have one, You may have a dirty needle and seat and allowing too much fuel into one of the fuel bowls. The way You describe it running this sounds like it could be the problem.

bashcraft

This indicates a vacuum leak.

joshtried

i have very minimal vacuum lines, like vacuum advance and that is tee'd into for the 350 trans. that is it. all other sources/holes are blocked, and have been since install. though, it cant hurt to check that..

joshtried

stupid vacuum cap.. was cracked on the side so i figured id remove it to see if this could be my "vacuum leak".. then the bastard had a huge hole beside the crack... ohh well.. 200 bucks later after changing the fuel pump, and probably screwing it up r/t welding and burning gaskets..... BAH! gotta come here first next time. (though it is 330 am here, so checking to "make sure" this is my problem will have to wait a few hours)

joshtried

ok, the vacuum plug did NOT fix this problem. it did not affect it at all..what next guys?

joshtried

and there is no sight plug

gingerbreadman1977

all the backfiring prob blew your powervalve. maybe replace that. a 1 year old holley should have no problem even if it sat for 2 months. i would pull it off and give it a total clean ,blowout and rebuild.

joshtried

well, *****.. i didnt want to do that...
guess its back to checkers in the AM

Timsride

I would almost bet money one or both Your needle and seat are dirty and need cleaning. The fact if You change plugs it stops it for a period tells Me that Your flooding it at idle which has to be either the needle and seat dirty, or Your float is way too high.

joshtried

i definitely think i needed a rebuild.......

gingerbreadman1977

holy s*#t dude what the hell is all that?
did you have mice living in it?
but i have seen holleys do something like this before but not to this extent.i think last time it was a reaction in the casting to race gas or ethanol

joshtried

all that crude in the top picture... i scrapped out of the 2nd picture (the bowl not the actually picture, for you slower folk :P)
i am only running 89 octane. the gas tank was dirty before i put gas in it, but i cleaned it out... apparently maybe not well enough. clean gas is coming out of the fuel line now though.

anyways, after all rebuilt, float set proper, all cleaned out and everything, i am having the same problem..

whats next?

Timsride

Did You clean out both bowls? There can also be garbage in the air bleeds. They are the brass plugs You see next to the main bowl vent. Looking at how much garbage was in there I would think Your going to be chasing this for a while. I had to take mine apart and clean it three times once each time I filled up, before it stopped. I had new tank new fuel lines, new filter, and rebuilt carb.You may need a new needle and eat if there was that much garbage going through it. I would thoughly clean front and back bowls, metring block all passages with compressed air. This may be a PITA.

snoopykissedlucy

WHOA...........my advice after the carb rebuild........place a big filter inline between the pump and the carb.

I bet someone removed any and all filters and ran the carb without them.