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A Learning Hobbist
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232 Posts
Discussion Starter · #1 · (Edited)
She just dies....

I have a Holley Carb 650cfm Double Pumper Model Number 4165. This is on 1979 Chevy truck K10 sb350. This motor was just rebuilt to pretty much stock specs.

Is it a blown power valve? This is my problem. When I starts it; it idles fines. When I give it any gas, in park or in gear, it stalls on out me. In order for me to get it into my driveway, I had to put it into 4low to get any kind of power out of it. I have set the timing at 10deg.

I would appreciate any help possible.

Thanks.

Steve
 

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Member# 3287
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2,625 Posts
If the power valve goes, the engine should run rich. Any evidence of that?

Sounds more like an accelerator pump.

I've never had a power valve blow out, even with multiple backfires.
 

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A Learning Hobbist
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232 Posts
Discussion Starter · #4 ·
Well I check the power valve and it's not that. The timing has been quadruple checked and thats right on.

Heres what happened. It starts up fines. When I give it gas, it dies. I can rev it up a bit, if I do it very slowly, but either way she snaps and then dies. Now I have had issues in the past with carb backfiring, and this is less like a popping and more like a snap just as it shuts off.

Thanks for any and all help.

Steve.
 

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I'm guessing this is a brand new or remand carb? if so it could be full of trash like willys36 and johnsongrass1 said.

I have heard of holleys coming out of the box cloged with peices of foam and cardboard.
 

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Jmark said:
If this problem came on all of a sudden, I"d suspect junk in a passage too. Here is a simple thing to try before pulling the carb apart. Get it running, then from the outside, try to wind it up some, 2500 is good, then slam the choke shut and hold it and open the throttle more. The extreme vacuum will quite often suck out what ever is in the idle or main circuit.

Also check the accel pump. With the engine off, look down the carb and slowly pull the linkage back, you should see 2 solid squirts shooting into the carb from the 2 nozzles.

Mark
Good idea. I have a kiddie car I built many years ago for my kids that has a B&S 5hp motor. When I let it sit a long time and try to start it, it acts like jrm's - tries to start then dies. If I just take off the air cleaner, hold my hand tight over the top of the carb and pull the rope a couple of times it sucks out what ever is plugging it up and it starts and runs like a dream.
 

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"May the Schwartz be with you"
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1,053 Posts
Jmark said:
If this problem came on all of a sudden, I"d suspect junk in a passage too. Here is a simple thing to try before pulling the carb apart. Get it running, then from the outside, try to wind it up some, 2500 is good, then slam the choke shut and hold it and open the throttle more. The extreme vacuum will quite often suck out what ever is in the idle or main circuit.

Also check the accel pump. With the engine off, look down the carb and slowly pull the linkage back, you should see 2 solid squirts shooting into the carb from the 2 nozzles.

Mark
If you decide to try this...be sure to keep your face and apendages away from the carb.
 

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A Learning Hobbist
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Discussion Starter · #10 ·
This problem has been since i have put the carb back in the engine after rebuilding the engine. I'll try some of the different suggestions. Thanks.

Steve
 

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Technical Support Barry Grant
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1,500 Posts
If the carburetor worked properly before, it may be gummed up from sitting, but you may want to check the engine. If you just rebuilt it, the cam may not be degreed in properly or your dist. may be out of phase.
 

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Something I do if a carbs been sitting for awhile is take a can of wd 40 and fill the floats threw the vent,then pump it out threw the accelerator pump,it soaks the gaskets,diaphram and seals that dried up,but also dissolves that white oxide very well.
 

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A Learning Hobbist
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232 Posts
Discussion Starter · #13 ·
Thanks everyone for all of your input. The problem turned out not to be my carb, but to be the location of my timing tab. The engine that I remove from this truck was a bit of a newer design, the engine that I rebuilt was the original, which is a 1979 sb350. When I put on the new timing cover and timing tab, the timing tab was in the wrong location. This engine, it should have been located at the top of the balancer so that I would be looking down on it. I had it to the right, so my timing was way off, even though I thought it was right on.

Once again. Thanks for all your help.

Steve.
 
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