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Old 08-15-2018, 10:02 PM   #5
liftlawssuck
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Join Date: Mar 2011
Location: MA
Posts: 353
Re: Backfire under loads

Quote:
Originally Posted by geezer#99 View Post
Have you checked and run the valves?
Tried more timing?
Checked the balancer/timing tab are accurate?
Done a compression or leak down test?
Yes I did check the valves and all were ok. Was really surprised they were.
I haven't tried more timing.
Balancer is questionable. There are 2 marks on balancer and I tried both of them without much difference. Which makes wonder.
I haven't done a compression check.

Quote:
Originally Posted by Shugalou View Post
I'm guessing you have already checked the plugs? Have you checked the gap? Yes plugs were new and gapped accordingly.

Is it good and warmed up when you get the backfire?
Yes it's good and warm.

Quote:
Originally Posted by Dead Parrot View Post
Possible exhaust restriction? Does it still have the riser valve? Is it stuck shut? That's a good question. I don't think it has that still but I didn't specifically look for it either. That's easy enough.

Since you replaced the intake and carb, the source of a lot of hidden vacuum leaks went away but might check all the hoses anyway. Yes a ton of leaks went away and I replaced all the rest of them with new. Again it runs way better just not great.

What are the plugs telling you? With the new intake, carb and now decent timing set, the plugs should tell you if any of the cylinders are out of sorts with the rest. I haven't pulled plugs yet since I put them in. I will put some more time on them and pull them see.

2nd on trying more timing. Since the engine was modified by a PO, possible the timing marks are lined up off.
Yes I will try more timing and see what happens. I thought the same thing as there as been some crazy things the PO has done. It also was acting like the timing chain had a lot of slack in it when trying to set distributor in and set timing. I never had 1 give me so much problems before.

I will try these and let you guys know. Thanks!!
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