helo for my bb mopar
05-06-2009, 09:14 PM
#1
Junior Member
SHOW GUEST
Thread Starter
Join Date: Dec 2008
Posts: 2
helo for my bb mopar
help wanted, complete new engine, cant seem to get a hesatation at the starting line, reves good and after stalling at the line it blows up and takes off, of course its to late,, and sugestions for this problem, have had the carb{ 850 speed demon} professionaly tuned, timing ok, what next, this engine is in a 3/4 ton, 4X4 dirt drag truck, 356 gears running in low range. starts good has super power after the stall is gone,,,please help!!!!
05-06-2009, 10:40 PM
#3
Senior Member
RACING JUNKIE
Join Date: May 2006
Posts: 2,044
Sounds like a carb issue.
First off, make sure all your air bleeds are clean. Then I'd take a hard look at the accellerator pump circuit(s).
C keep in mind it could be several diiferent things...
You might try some need bigger squirters, The accellerator pump (s) have cams, there are 2 holes on them, try moving the screw to the next hole and see how it does, you may need to go up to a 50CC pump kit.
Its kinda hit and miss, try one thing if it doesn't get any better, then put it back if it does then leave it alone and move on and try something else.
Another thing to try would be to richen up the primary main circuit - go up a couple jet sizes and see how it responds if it gets better go up 2 more.
If you have a vacuum advance make sure it hooked up to a ported vacuum source and not manifold vacuum, also bumping up the timing a tad will help bog.
Goodluck and let us know what it took to fix it>Cp
First off, make sure all your air bleeds are clean. Then I'd take a hard look at the accellerator pump circuit(s).
C keep in mind it could be several diiferent things...
You might try some need bigger squirters, The accellerator pump (s) have cams, there are 2 holes on them, try moving the screw to the next hole and see how it does, you may need to go up to a 50CC pump kit.
Its kinda hit and miss, try one thing if it doesn't get any better, then put it back if it does then leave it alone and move on and try something else.
Another thing to try would be to richen up the primary main circuit - go up a couple jet sizes and see how it responds if it gets better go up 2 more.
If you have a vacuum advance make sure it hooked up to a ported vacuum source and not manifold vacuum, also bumping up the timing a tad will help bog.
Goodluck and let us know what it took to fix it>Cp
05-08-2009, 09:14 AM
#8
Senior Member
MASTER BUILDER
Join Date: Mar 2008
Posts: 192
I have had horrible luck with brand new BG carbs, with metal filings everywhere in the carb. I rebuilt every carb b4 thay were sold, or else there would be many problems. Take the whole carb apart and clean out all the filings from inside, and it makes a world of difference.
