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Can problem w/carbs cause power loss?

Posted: Wed Apr 04, 2007 9:38 pm
by renobdarb
I'm havin' some issues with power loss in my '78 bus... It seems to run just fine in 1-3 gears, but when I shift into fourth it seems to flaten out and bog down, and just doesn't accelerate like it should... If there's even the slightest uphill (and I mean slight... doesn't have to be a hill, just a rise in the road), it won't accelerate and sometimes even slows down, even with the gas mashed down.

I've tried just about everything I can think of... I've adjusted the valves (twice), checked the timing, even installed a new SVDA distributor (was going to do that anyways), and checked the timing again. Same problem.

Results from a compression test told me the valves came in between 92-110.

The only thing left are my carbs (dual Weber 44's). Could out-of-sync carbs cause a loss in power?

Seriously, this is really annoying me. Any help would be appreciated.

Posted: Thu Apr 05, 2007 6:55 am
by Whip618
Is this a new problem to your bus or the reoccurrence of a porblem that is getting worse?

Usually out-of-sync carbs will not cause your problem but you will see a rough stumbling idle and ragged acceleration. What type of fuel pump are using to supply fuel to those Weber's?

Phil

Posted: Fri Apr 06, 2007 5:51 pm
by Amskeptic
I think this thread was best located in the trouble-shooting forum so we all can chime in with the different scenarios. Right now we cannot say with any certainty that this is a fuel delivery problem. Was it the other thread you posted that mentioned high altitude? Aftermarket carbs often respond very poorly to high altitude because they are already on the rich side. You can advance an additional 3* timing and lean out the mains as long as you are above 5,000 feet. You must retime and readjust the mixture when you get below 3,000 feet.
Colin
(unless, of course, you are not the high altitude poster)