B and S pulse carb

Al Smith

Mac Daddy
Mar 6, 2005
Northern Ohio
This question arose about how a B and S type carb works,either here or some where else,doesn't matter.

It is rather timely however that the carb on my leaf vac caused me to swear and cuss and jump around like crazy man here of late.Well.I bite the bullet and removed the danged thing and gave it blow out with compressed air,should work,find out tommorrow.

That said the way the thing works is it sucks up through the little long tube,through the diaphragm and drops the gas in top of the tank.That area of the tanks acts like an open float bowl,sort of but no float.The gas is pumped continously,just over runs back to the tank.

From this open bowl the gas is drawn up through the fixed jet,with the screen thing on it.It has another fixed jet on the opposite side,brass.I suppose it is the idle.??
Hey Al
Just in case you didn't know, before you put it back together, take the diaphram cover and using a fine grit sandpaper, 600 is what I use. Find a good flat surface, then making a figure 8 motion sand the plate. This will keep it from leaking. The worst thing about these carbs is getting them off and then back on.
See Ya
Chisel, the worst thing about those carbs is those carbs.

I feel for ya Al, one of those things drove me nuts untill I replaced the entire carb and tank, havent had any trouble since.

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  • #4
One of the checks was stuck from setting I suppose.I've had that thing about 8 or so years and it's never set outside except when in use.I doubt it gets 4 hours of running time per year but in that 4 hours it will do more work than I can do with a rake in a week.

Everybody has something they just detest,raking leaves is my thorn in the side,dispise it.:(
I quit raking my leaves. What the hell for, I just mow em in and life goes on. My yard looks a little ratty for a couple of weeks before the snow falls and then in the spring they're basically gone. Frig raking leaves, frig mowing grass, I gotta figure out how to get rid of my lawn.
I don't but it just keeps on growing, by about mid august usually I'm done with the mowing and the grass takes on a nice shade of brown.:D
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  • #8
I would not worry about the leaves either but due to the fact I live in the woods,that shade grass doesn't take too much to kill it.

Back to the carb.It wasn't the problem.It's kind of embarrising but it was carbon under the valves.If I screw up,I admit it,I did so I do.:hammer:

Small engine 101,small air cooled engines need attention to the valves about every 50 hours.Now most people don't know this.Me being a graduate of Briggs factory school should have ,duh and double duh.:(