Need help getting car to idle.

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64physhy

64physhy

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I can't get my stroker to stay running under 2000 RPM's. When it gets below 2000 RPM, it stumbles a little, then dies. The carb is a proform 750. Float levels are good, I have the idle mixture screws turned out 1 1/4 turns to start, until I can get it running to fine tune them. Primary jets are 75's, and I think the secondaries are 84. I just replaced the PV, thinking that might be the problem, but didn't fix it. I'm going to go check around the base of the carb for possible vacuum leaks now, but it shouldn't have any.

Timing right now is at 30 (locked out on MSD E-curve) (will adjust when I can get it to run)
Cam duration is 237/242 @ .050 with .584/.592 lift and 108* LSA
Edelbrock RPM Air-Gap intake.
Hughes Iron Ram Heads, ported with 2.055 intake valves.
 
Well that wouldn't be the first Proform carb I've seen that was not right.

Is this a new development, a new build or or just an update on the engine.
 
Engine is newly rebuilt. It started and ran fine for break-in, and I drove it on a couple short drives and it worked, but needed to be tuned. The last time I drove it, it started with the stumble and started to not idle well, but would run at about 1200 RPM, then died going down a hill. Since then, it's just gotten worse. It almost seems like it's only getting enough fuel from the squirters, but not from the jets.
 
Yeah that carb is messed up. Take it apart, look for any contamination or debris. Clean it thoughly and blow out all the passages with compressed air. It sounds like something is clogged and it could be very small.
 
I have a new AED850HO on my 410 with a .631 lift cam 242@258 108 LSA.The car idles at 1000rpm no problem.Timing is at 36 with MSD dizzy locked.Summit now sells the AED carbs.It,s a hogged out Holley dp and has excellent responce.Good luck.
 
pettybludart said:
I have a new AED850HO on my 410 with a .631 lift cam 242@258 108 LSA.The car idles at 1000rpm no problem.Timing is at 36 with MSD dizzy locked.Summit now sells the AED carbs.It,s a hogged out Holley dp and has excellent responce.Good luck.
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I can't afford a new carb right now. I did find that there was a vacuum leak around the base gasket, so I replaced them. I checked the base plate to see if it's warped, and it's not. Now, I can't even get it to start. I'll take it apart tomorrow and make sure it's clean. I had both bowls off earlier, and there was a small piece of plastic in the rear bowl, I think from the clear sight glasses I put in, so I took those out. It's possible there's more in there that I missed.
 
if you changed the pv ...check to make sure it is seated correctly...make sure the gasket is not cocked off to one side....otherwise you have a internal gas leak
 
I cleaned the carb really good and checked out the PV. It started for a while, but still won't idle. I didn't get a chance to let it warm up completely to see if it will idle when warm...heres why.

It ran for a couple minutes, and I tried letting off the gas a little and it died. When I tried to re-start it, it kicked back and ran backwards for about 3 seconds, several revolutions. WTF?!?! The timing is locked out at 30* with a start retard of 10 degrees, so I'm pretty sure it's not the timing. What all do I need to check now?!? Could this have caused the timing chain to jump? Please Help!!
 
I wondered that, but it did this as I was trying to start it. It only cranked about 3 times, then kicked over backwards.

And, I checked the plugs before this happened, ant they said it was running rich. I leaned the mixture by only about half a turn from what it was.
 
you should only need about 1/2-1 turn out, usually 3/4 turn out all around.

plug the pv all together and see if it runs/idles.

have you done a vac reading to select the right pv, I wonder if you checked it now if it hadn't gone up ....
 
They are 1 1/4 out right now. Haven't been able to get it to run good enough to read the vacuum to figure out what size PV I need. It has a 3.5 in it now.
 
So that wouldn't cause anything that I should be overly concerned about? Skipped timing chain or anything?
 
Had sort of the same problem of getting car to idle. I ended up having to adjust the secondary butterflies. only cracked them a little and it took care of problem.
 
Ohio Ironhead said:
Had sort of the same problem of getting car to idle. I ended up having to adjust the secondary butterflies. only cracked them a little and it took care of problem.
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Thanks. I'll try that, but I'm still worried about it going backwards.
I went out and richened it a quarter turn and retarded the timing another 5* (so it's at 10* now below 600 RPM's and 30* above 600 RPM). Started right up, but once that initial bit of fuel from the squirters was gone, it died, and kicked backwards again when I tried to re-start.
I have another carb I might try, but it's only a 650, so I don't know if it will be any better.
 
did you dial the cam in yourself?

yeah, maybe try the other carb.

I can come out & take a look at it if ya want, I have other 750 carbs hanging around [that are known to work fine]
 
1wild&crazyguy said:
did you dial the cam in yourself?

yeah, maybe try the other carb.

I can come out & take a look at it if ya want, I have other 750 carbs hanging around [that are known to work fine]
Click to expand...

I put the cam in myself, but just lined up the marks, I didn't degree it. I know...I should have.

I'd love for you to come check it out when you have time.
 
well it's up to you if ya wanna pull the cover and degree the cam.

I tell ya though...they almost always come out advanced, sometimes a lil sometime a lot.

it took 8* retarded to get 2* advance with a JP performance billet time set and mp cam.
it took 6* retarded to get an engle cam 1/2* from straight up with a mancini billet time set.
Tomorrow after I get done changing out a steering coupler on another guy's dart, I can cruise over.

just shoot me a pm.
 
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