Help won't start older B&S 3.5 hp 148cc

Mini Bike & Go-Kart Parts

Not a Briggs engine- That is a Tecumseh H35. The carb needs complete disassembly, a THOROUGH cleaning, and (most likely) rebuilding. I would advise rebuilding it anyways as long as you have it removed and disassembled. Download for free the Tecumseh repair manual that has been saved as a "Sticky" in the Tecumseh engine topic section of this forum as you are going to need it. Youtube is your best friend right now as there are lots of good videos on how to clean and rebuild these carbs, which are known to be a bit finicky.
Last edited:
You aren't getting any fuel to your float bowl.

Clamp the fuel hose, or drain the fuel from the tank.

With a 7/16" wrench, remove the main jet assembly on the bottom of the engine.

Tap the bowl on the bottom of the carb a bit to loosen it up, and carefully pry it off the carb.

(You will want to pay attention to the bowl gasket and the gasket for your main jet assembly)

Slowly raise and lower the float and watch to see if it actuates the little needle. This is the system that meters fuel from your tank to your carburetor.

You can pull that float pin out and remove that needle and spray carb cleaner in it and reassemble. Note that the needle sits against a tiny O ring inside, so don't blow it out with too much air pressure.

This is a common problem with these carbs on engines that have sat for awhile.

Alternative is to remove the bowl as I said, clamp the fuel line with vice grips, add some fuel to the tank, and remove the vice grips. Move the float up and down, and fuel should start and stop. (Catch the fuel in a rag) This is the fastest way and how I do it.