I Have 700 Nxt Aprox 100 Hours Replaced Worn Inpellers And Housings Went Tocheck Oil Level In Fuel Pump Housings And Found It Was Over Full With Gas. I Am Assuming The Pumps Are Bad? The Boat Has Been Sitting All Winter!

The sea water pump cavity for the fuel pump should be refilled with Mercruiser High Performance Gear Lube (same lube that is used in your drive unit). The lube inside the cavity lubes the fuel pump arm as it is riding against the cam inside the sea water pump housing.



The presence of fuel in that cavity is very common, it does indicate that fuel is leaking into the cavity from the fuel pump and should be replaced. If the amount of fuel in the lube cavity is minimal, many technicians will go ahead and re-use the fuel pump but that is not the official recommendation from Mercruiser, they recommend replacing the pump if any fuel is present inside the sea water pump lube cavity.

Pretty common issue. I used to change the lube on my 525SC pump at least once a year.

Thanks ,i Think I Will Drain And Refill And Keep A Close I On It For Now!

One of the worst setups ever designed....

Just replaced the lube on my brothers boat yesterday. I don't think it had every been changed. No fuel, but no lube either, I cleaned everything, filled with gear lube, hope for the best. Good thing is I did not see any metal shavings. I would recomend changing the impeller every 2 years and at the same time replace the gear lube for the fuel pump cam. Like Griff said every year would be the best.

I agree with changing the impellers mine were both ready to self destruct that would not have been good!