popping through carb

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Apr 18, 2006 | 08:27 AM

#16

TigerDan

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Joined: May 2004

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From: The hills of No. Calif.

Well, try the EGR as holland501 suggested and then let us know if that's it.

May 3, 2006 | 07:06 AM

#17

machipman

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From: Magnolia Ms.

Update, Rebuilt extra carb I had and also installed the EGR plate and new gaskets. Still have popping through the carb and seem to have a worse vac leak. Only getting 15 on the vac gauge had 18 before and the idle screws barely make a difference when adjusted, been real busy lately so am trying to play with it a little at a time. Also, I have the brake booster hooked to the T off the manifold, EGR hooked to same T, PCV is going into big port on carb, Vac advance hooked to passenger side front port on carb and that is all, does this sound correct? Get max vac with the timing set between 7 and 9 degrees, also seems to idle smooth at that setting. Will look for vac leak before I continue looking deeper.

May 3, 2006 | 11:11 PM

#18

70T351W

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From: azle texas

After reading your post trying to figure out the problem I was also thinking about mine. Your problem sounded to much like mine. I kept saying I didnt have a vac leak, I have checked many times. You mentioned spraying starting fluid around the intake and carb which I have done. So I figured what the heck I'll do it again if it doesnt work I will have cleaned my carb and intake. To my amazment as I sprayed around the intake I found a vac leak. It must have got worse enough over time to raise its ugly head. Hang in there and dont give up the answer will come to you. I am hoping I got the answer for my problem.

May 4, 2006 | 07:34 AM

#19

machipman

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From: Magnolia Ms.

I've checked everything at least 3 times so far. But it is the simple things you miss that will mess you up. Plugged all vac lines and it still pops. Adjusted timing and carb and finally got 18 on the vac gauge. Pops still. Decided to double check vac advance and danged if it isn't working, can't get a vac at all on the thing, must be a bad diaphragm. Will change that today, I still think it shouldn't pop even without it hooked up, but have never tried before on another motor. If this doesn't work I'm wondering if the carb is big enough, I don't know the full history of this motor so it may have been gone through and bored out, heads may have been done also so I'm not for sure.

May 8, 2006 | 08:28 PM

#20

jsoko

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Joined: Apr 2006

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From: Cherokee Co. GA.

if pop happens when you rev high intermitantly check for bent push rod or rocker out of adjustment, possible wore off lobe on cam

May 9, 2006 | 08:55 AM

#21

machipman

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From: Magnolia Ms.

Another update in the carb saga. See if I did this correctly. Wanted to check firing order, this is what we did.

1. Set #1 at TDC (0 on balancer, piston at top, felt compression, rotor pointing at #1 on dizzy)
2. Turned motor until the next cylinder came on compression stroke, turned out to be the #3 ( balancer turned about 120 degrees)
3. Continued, #7 was next and then #2.
It seems we were using the wrong order as everyone has suggested, the problem is, we changed order to 1-3-7-2-6-5-4-8, now it won't start at all.
When timing is retarded it backfires through the exhaust and when it is advanced as far as the dizzy will let me it tries but won't start.
Will pull dizzy out tonight and rotate advanced 1 tooth. Does anyone have an easy way to line up the oil pump shaft?
Does all this sound right for the problem we are having?
Carb is a stock Motocraft 2 BBl
If this fails I will pull of valve covers.

Last edited by machipman; May 9, 2006 at 08:56 AM. Reason: add info

May 11, 2006 | 06:53 AM

#22

machipman

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From: Magnolia Ms.

Update, I hate when people don't post when things are fixed, FrankenTruck lives. After re-doing the firing order and a vac leak and moving the dizzy 2 teeth it runs and drives fine. Some minor tuning but it is good, thanks to all that helped.