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Dual solex downdrafts

eastcoastitalian

eastcoastitalian

Contributing Member
Put the dual solex downdrafts and intake on my bb140 and just can't get it right!it either idles perfectly and hesitates and pops when you first gas it, or after adjusting the the air screws will idle very rough but no hesitation or poping when gasing it. Either way it revs fine though, very smooth, just on the initial first shot you give it to gas it, have experimented with a couple different idle jets, tryed adjusting the accelerator pump, and tryed adding spacers between the carbs and intake, no change with any of it. The set up came off an aq145. Any idea's would be helpful,thanks.
 
If the engine runs well at high idle, I would start by first synchronizing the carbs with a Uni-Syn tool (vacuum flow gauge), then adjust the idle mixture and idle speed. You can also try using medium or high grade octane gasoline, then set the distributor advance at 10º instead of 6º.

How much are you opening the idle mixture screw? I would start with about 1-1/4 turn.
 
Ok, thanks will try after work tommorow i think autozone sells those tools for around $30.00, as far as the spacers go i have left them in, but i notice no difference with them, should they stay or go? I know the schematics show them on almost all the carbs, they're sometimes used in cars for a little better throttle responce and a bit more top end, but was'nt sure if the same applys in the marine synario?
 
Are you sure your accelerator pumps are working to their fullest?? It sounds as when it idles fine but then pops on accel that your not getting a good squirt and then when you adjust your air mixture and it idles rough it is way rich and is making up for the just off idle hesitation or pop that the accel pump is lacking. ????
 
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