Need help with my 50hp boat outboard

[Pinhead]

Hi guys, I’m having a problem pinpointing the issue with my 1992 2stroke Nissan 50hp tiller motor. I’m not getting water up to the top and out the drain hose. I changed out the impeller but still no water. What happens after the impeller? Does the water continue up the water pipe into the head and then expelled out the drain? I had help with someone knowledgeable about impellers help me change that, so let’s assume that’s not the problem.

What else could be wrong. The water pump system looks relatively simple, what am I missing?

Thanks,

Dan

[petew]

Weeds pluging the water channels ? Try a reverse flush with a hose to clear the water jackets and passages.

[Pinhead]

Thanks for the reply. We tried that and had water dribbling out the bottom intake.

Dan

[petew]

Originally Posted by Pinhead

Thanks for the reply. We tried that and had water dribbling out the bottom intake.

Dan

There should be more than a dribble I would think. The only thing to do is flush and clear the passages. Does it have a thermostat? if so it can be pluged. You have to open the passages . Are you sure the impeller drive is not also broken?

[Pinhead]

Looked at the thermostat, thought it would work regardless. Am I wrong?
New impeller in and that part I believe to be good.

[petew]

If the thermostat is stuck closed it won't flow, , and it also won't open until the motor is hot.

If it was mine I would pull the thermostat, test it in a pot of boiling water , or over a candle to make sure it opens when hot or just replace it without testing it. While you have it out do some flushing to make sure there isn't any restrictions from weeds,sand,or old impeller pieces.

[Half Pickereled]

Originally Posted by Pinhead

Looked at the thermostat, thought it would work regardless. Am I wrong?

New impeller in and that part I believe to be good.

Not necessarily, some do and some don’t have a steady tell tale stream...old v4 Evinrudes will have a steady stream no matter what. But for example a Mariner 15 hp will only flow when the thermostat is open so it’s intermittent and can make a grown man faint if he’s not aware of it.

If you have access to a temperature gun.... run it and zap all around the water jackets and see what temp your running at.