Got a murray push mower w/3.5 hp classic 9d902 2005 b2 00122851 b&s motor--primer bulb rotted away-installed new snap in bulb--opened up carb checked out for any gummy build up or bulb fragements -found none----primer won't squirt gas in carb unless you pour a little gas in carb--starts great then & bulb squirts---but automatic throddle won't work--runs rough & if you push into tall grass it gors dead----what did I do wrong??

Could be a small, microscopic piece of debris in the carb, or you may have other damages within the carb. Remove, clean and inspect again.

Mowerman----cleaned& checked carb again---still same probs.---these little carbs seem to be inexpensive on line----does the auto throttle work off vac in carb or piston? If I manualy move lever motor revs up fine! Wondering if new carb is answer!

You took the carb apart, including the mixture screws and fuel valve and cleaned in carb cleaner, right? I suspect the fuel valve is hanging up.

Usually there are two mixture screws. The large for fast idle and the smaller on for slow idle. Turn them in all the way and back out 1.5 turns for the initial start. Then adjust fast and slow idle.

Your throttle linkage is hanging up or a spring is missing. The flywheel is a small fan which helps cool the engine, but it has another use. The air pressure from the blower moves a flap which moves the linkage on the carb. Keeping the speed relatively constant.

Check the parts diagram on Home - Briggs & Stratton (http://www.briggsandstratton.com) to see if you missed anything.
A rebuild kit will set you back about $15, but you should not need it unless the diaphram is bad (assuming this is a diaphram carb).

No new carb.

o.k. here we go again---cleaned some more-put in a new plug----can't get b&s home site to run on my puter--so no diagram to go by-----primer now works unless you run out of gas or let it set over nite----k.i.s.s.---i don't see any adjustment screws on this thing--its just a plastic carb. Mounted on gas tank--whole thing goes on what seems to serve as intake manifold?? 2 bolts mount tank & all on motor-----lever that hooks to linkage & 2 springs comes out from under coweling that covers start rope assby.---are there any screws up under there? -------lubed what I could spray on lever (w/out removing coweling)------ran good for 10-15 min.--died then back to slow rough idle--surging up & down barely running------if flywheel provides air to increase & lower rpms how the heck does it work??

Try Firefox

Use www.searspartsdirect and use 9d902 as the model. The carb is only $25 and the speeds seem fixed with no adjustments.

Item 200 is the governor. There could be gunk around the screw (Item 425).

You might want to take off the blower housing (cowling).

Have you ever put your palm of your hand out of your car window perpendicular to air flow. Ever notice the pressure on your hand as the car's s peed changes. Well guess what, that's the same principle except the spring provides a counter-balance to the throttle position and the flywheel air (not air for the fuel) exerts pressure which exerts a displacement. In effect, the throttle position provides the setpoint and the governor moves until the mechanical forces are balanced. The control element is the throttle plate.

If you don't find anything wrong, I'd suggest replacing the $25 carb.

New high octane fuel. Run some spray carb cleaner slowly through the air intake while the engine is running.

I took my john deere js63c lawnmowers carb of to check it out due to it not turning on. I found out that there was water in the float area of the carb. It's a briggs and stratton carb I dried the carb up I blew the lines out and like a idiot as I was blowing out through the top injector a pin from the float area blew out that was connectec to the float I put the pin back in and connected the carb back to the housing of engine. I filled it up with fuel I primed the carb and through the primer a stream of fuel comes right out. I'm trying to find out there was something else attached possibly to the pin. I would greatly appreciate a response.

I would say you blew the needle seat out of the carb.

There is a diaphragm on between the carb and the fuel tank, that needs replaced. Buy a carb rebuild kit.

No