Re: Motor too low causes backed up exhaust?

[johnyrude200]

This is the pan, exhaust housing, and gearcase from that other motor, with a different powerhead. The other powerhead got transplanted to another pan/leg/gearcase and will be converted to manual start since the electric start orifice on the front of the crankcase was not salvageable.

So I buttoned up the exhaust bypass with 2 new gaskets and still have the same issue. Neutral, pumps plenty of water, in gear, anything much above idle and the water gets shut off. As soon as I shift into gear and the RPMs drop, water pumping drops off too, HOWEVER, when I rev up to RPMs similar to what it has in neutral/not under load, the water pumping basically dies off quickly.

I pulled the motor from the test tank and will pull the gearcase off tomorrow morning to look at the gaskets/o-rings. If all looks good (which I’m pretty sure they are), I’ll mount the motor on my test boat and give it a spin.

This is an odd one to me. I know that the powerhead is OK, I had all of the water jacket apart and there are no clogs anywhere. Thermostat is OK, new impeller. There is something going on either with

A) air bubbles in the test tank getting sucked into the water intake screens on the gearcase
B) somewhere leaking exhaust pressure from the powerhead finding it’s way into the impeller housing
C) faulty seal(s) in the gearcase or driveshaft water tube.

I will do my best to eliminate each of these 3 causes tomorrow. Hope I can get this resolved by end of day because I need to get on my next project…falling behind!!!!