Mariner 15HP

[Jay Jay]

Hello again and Good morning all, My brother inlaw has a Mariner 15HP and he thought he had a water problem as it was pumping very hot water and at a slow pace, so he asked me to have a look, I changed the whole water pump and put it all back together, now I don't know if this is a problem or not but it seems to alternate between pumping water quite slow and then at the normal rate ( very good and fast ) so it cannot be a blockage issue, can anyone tell me if this normal please?? ( The engine is less than 10 years old )

 

[Graham376]

Any sign of the engine overheating or is it just the flow through the tell-tale which varies? Have you tried clearing it out with bit of wire or drill bit?

 

[Refueler]

10yrs old ? Is it 2str or 4str ?

My 2str 20hp - basically same O/bd - if yours is 2str - but just up on power has a pretty steady flow of water ... of course the rate increases with throttle .. but even at idle - there's a reasonable steady flow ....

I would have given it a Rydlime / Fernox flush first before spending money on parts ..... to make sure all channels etc. are clear. Sounds to me as if original problem is still there even after new parts ?

 

[Jay Jay]

Thank you fellas, yes I can hold my hand on the piston block for as long as I like, and as I engage foward gear and use a bit of thrust it has a very good steady flow, but on idle that's when it's intermittent , would that be the thermostat opening and closing maybe ??

 

[Refueler]

Sounds as if its OK then ...

 

[VicS]

Thank you fellas, yes I can hold my hand on the piston block for as long as I like, and as I engage foward gear and use a bit of thrust it has a very good steady flow, but on idle that's when it's intermittent , would that be the thermostat opening and closing maybe ??

If you are testing it in a tank maybe you do not have it immersed deeply enough. The water level should be well above the water pump.

 

[QBhoy]

Hi. I had a mariner 10hp 2 stroke. Same engine as the 15 if of a certain era around 90’s into 2000’s. It had a thermostat and altered between a lesser and greater flow of tell tale. Hope that helps