90HPV4 is cutting out above 3300 RPM as if starved for fuel. Pumping primer fixes it

[Fed]

Sorry Todd I had the wrong motor, carry on.:facepalm:

 

[oldboat1]

A leaking lower crankcase seal could cause the engine to lean out. Might check by spraying some carb cleaner around the base of the engine while running (shield the carb intake). If the rpms change, the lower seal may need replacing.

 

[toddschubert]

Thanks! That gives me another idea...
Spray soapy water all over especially Lower base and pressurize case with air hose. Hmmmm

 

[Joe Reeves]

Thanks! That gives me another idea...
Spray soapy water all over especially Lower base and pressurize case with air hose. Hmmmm

If it were me, before doing anything else, I would remove all the spark plugs so as to obtain the fastest cranking speed possible, then do whatever is necessary to gain access to whatever fitting applies pressure to that fuel pump... then with my finger over the fitting or a hose attached to that fitting, crank the engine over remotely. That should reveal if the pressure exists or not.

Remote Cranking: Use a small jumper wire from the large battery cable terminal of the starter solenoid to the small 3/8" nut terminal of the solenoid that energizes the starter solenoid. NOT the 3/8" nut terminal that leads to ground!

If you do this Todd... let us know the results.

 

[racerone]

There are 4 seperate crankcases !---Which one had the reed that was not quite closed ?