Craftsman 5.5 HP Briggs won't Prime.

The carb does not have a prime ball built into it. I can get the motor running by pouring a little gas in carb, then motor seems to run fine. When warmed up it starts ok. Not great but ok.

I have put some carb cleaner in the carburetor and some sea foam.


It just seems to not start when Choked and cold without some starting fluid / gas.

See attached pick of carb.

Any suggestions?

Five things can go wrong with that carb and need to be checked. Any one or combination can result in your problem.

1. Fuel pump diaphragm on the side of the carb is bad and needs replacing. Not pumping fuel into the tank reservoir.

2. Gasket between carb and tank not sealing properly, or warped tank. This will allow an air leak in the tank, not allowing fuel to flow.

3. Gasket between carb and block bad. An air leak here will cause a very lean mixture, too lean for starting.

4. Pick-up screens on the end of the pick-up tubes in the tank and/or reservoir are plugged.

5. Idle mixture screw is set too lean. Initial setting is 1 1/2 turns out from lightly seated, then adjust when engine is warm for smooth running.

Thanks. I will check those 5 things.

On the last one you mentioned the idler screw. I see two screw that can be adjusted.

1. Closest to the engine block
2. Farthest from the engine block.

Which is which?

Roger

One closest to the block is the idle speed screw, controlling the throttle at idle. The other one, should be larger, is the fuel mixture screw, this is the one which may be out of adjustment. I post wrong on this one, should be adjusted a full speed, not idle. Sorry.