1998 130hp two stroke. Replaced fuel pump, and will not start

[Excalibur130]

Fuel pump diaphraghm had a tear. On one occasion, priming with primer bulb, fuel filled the combustion chamber and engine would not turn over. Took plugs out and engine turned over and started again. Got new Yamaha fuel pump. Engine will not start. Gasket from fuel pump to head looks o.k. This pump is vacuum driven? Could fuel have leaked from old pump to somewhere that could stop the vacuum? Anything that needs to be drained?

[TownsendsFJR1300]

Yes, the pump works on vacuum: https://www.boats.net/catalog/yamaha...8/130tlrw/fuel

Did you remove the spark plugs and CRANK / SPIN over the engine (plugs out) to remove excess fuel that made it into the engine?
This is to include fuel in the CRANKCASE, not just the top end.

Sounds like it's flooded...

The spark plugs also need to be dried and cleaned.

The engine should spin over with the ignition safety clip removed (kills spark).

[99yam40]

that is something I never thought about before,(How to clear out the extra fuel from crankcase).
there should be crankcase re-circulation check valves and lines to help do that over time.

but then I never knew about anyone priming a motor with a defective pump so much that it locked up a motor before.

the pump should only run off of one cylinders pulse port, so it should not keep the motor from starting. just flooding one cylinder should not stop a motor from starting

[TownsendsFJR1300]

that is something I never thought about before,(How to clear out the extra fuel from crankcase).
there should be crankcase re-circulation check valves and lines to help do that over time.

but then I never knew about anyone priming a motor with a defective pump so much that it locked up a motor before.

the pump should only run off of one cylinders pulse port, so it should not keep the motor from starting. just flooding one cylinder should not stop a motor from starting

I've had many small engines (both come in like that) and one's that the carb leaked fuel into it (piston / port configuration).

Turn the engine upside down, pull it a couple of times and watch ALL the fuel come out. A blast with the air compressor works. Even then, once it starts, smokes like a pig till all the oil/fuel is burned up...

As for priming till it locks up, if the pump is leaking into the crankcase, and you keep pumping fuel, the fuel is going somewhere. Apparently into the top end at least.

Cranking with the plugs out assures no hydraulic lock/damage and eventually gets most of the fuel out..

[Excalibur130]

Thanks for comments. I will look it over again at weekend and see. I had cleaned the plugs after fitting new pump. Will crank it over again with plugs out and kill switch on to see if it sorts it.

[pstephens46]

Check to make sure plugs are sparking in the first place...

[zenoahphobic]

If we are thinking that there is a lot of fuel still in there, then a cautionary note: be careful with checking spark with plugs out not to cause a 🔥

[TownsendsFJR1300]

With the safety kill switch clip OFF the switch, shouldn't be any spark..

[rodbolt17]

the pump is driven by vacuum and pressure.
keep a fire extinguisher handy.

[Excalibur130]

Got engine started. Took airbox off with engine tilted up. There was fuel in airline to bottom of airbox.Once this cleared, it ran.