Re: 15hp exhaust & water leak…why?

[johnyrude200]

There were two holes by the upper rubber boot/seals connect. They looked man made, but who knows. The solution was I transplanted the powerhead to another exhaust leg/transom bracket. Issue solved. This is a ’75 motor and has the square exhaust with the rubber seal at the bottom.

I’ve fixed the fuel system; the low speed needle was missing the bearing so the carb was sucking air in causing bad operation. It still has the needle out a turn and a half or two; but the motor is running fine at all ranges other than your typical blubbering until it clears out.

New issue though is it is overheating. I have replaced the impeller, run with and without a thermostat, and torn the motor down completely for a 4th time and have yet to discover and clogs. I pulled the cylinder head and thermostat cover, and also pulled apart the exhaust cover and there were no clogs. I gave everything a once over to clear out any buildup of sediment.

I ran the gearcase separately with a screw gun and it’s pumping plenty of water, and I hooked up a hose to the water intake of the powerhead and water is passing through the powerhead freely. I’m a little stumped on this one…again. The motor doesn’t overheat rapidly, it seems to pump little water (as indicated by the water/exhaust blubber hole), then pumps a good amount when I throttle up, then as it’s starting to run hot the water supply drops off to basically nothing.

I would say perhaps I am creating an air pocket in the test tank, but no other motor has been doing this recently, and I have been working on a lot of these 9.9/15’s in the last few weeks. So I don’t think it’s an air pocket issue. The water level in the tank is well above the impeller housing.

It’s not the water intakes on the gearcase (learned my lesson last week), those are clear. What has me scratching my head is I just worked on one of these last week and that motor was pumping a TON of water, and was a ’75 model as well.

I’m putting this motor back together in the next few minutes and will double-check to make sure I didn’t accidentally put the water tube into the impeller housing outlet and fold over that grommet, but I doubt that is the problem.