OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Briggs & Stratton Engines Briggs & Stratton 375 running rich

Hi All
Hoping you can help with a problem I have with a rover mower with a B & S 375 sprint motor. It's running rich and will not rev out. I have cleaned the carb,fitted a new diaphragm and gasket,throttle spring and governor spring but still running rich and will not rev out ?
your thoughts would be greatly appreciated.
Thanks

Need the model and type number but I thinking you probably have those carburetors that has a metal jet in the carburetor that is known to fall out. Once gone the carburetor will be over rich or it can be just loose. Worth checking.

The carburetor on the left is the one with the metal jet and the one on the right is the one we have here in the USA and some the Australian models also have which is all plastic. There is also a small rubber o-ring under there holding the nozzle.

Further to AVB's comments, i would also try a new plug or a known working plug. i had the same symptoms once upon a time and after stripping and cleaning the carby several times it turned out to be the plug.
Let us know how it goes.

Thanks AVB I have the plastic carburetor. Is there an o-ring in the plastic carb, if so do you just flick out the black plastic cap in front of the main jet or does it unscrew ?

I will get the model number when I get home.

Thanks Big ted. yes I a fitted a new spark plug with no luck.

Cheers

Yes. It is complete nozzle with jet. It is removed as follows:

• Remove throttle vane and shaft.
• Press out nozzle carefully using a flat tip screwdriver or similar flat object.
• Noozle is held by snap fit so when pressing back in make it snaps in and is flush as previous seen.
• In following image the o-ring is circled.

Hope this makes sense.

Thanks AVB
Great info,greatly appreciated. I will give it a go at the weekend and let you know how I go.

Also my model is 98902, type 2163 E1, code 00090652

Thanks mate.
Cheers

Running out of ideas, replaced nozzle jet o-ring. Still the same, running rich with air filter on and no revs + surging up and down + pumping a little black smoke. Air filter off, runs smoother, no black smoke and no surging still no revs. but it will rev if I push on the governor? So I shorted the throttle spring it just started surging up and down again with no revs?
your thoughts would be greatly appreciated before I go mad.
Cheers