cooling problem 25 hp

[MTX]

Just did complete overhaul, motor runs like a top with water muffs on. Water flow is great, tell tale hole flows good. However, When motor is placed in barrel or in lake it has very weak flow nearly zero. Any suggestions?

 

[flyingscott]

What year 25 and serial #

 

[MTX]

Not sure of year . S/N 689 100475
I believe it's actually a 30AE

 

[flyingscott]

That is a yamah/mariner motor late 70s to mid 80s. When you put the lower together are you sure you got the water pipe lined up perfectly

 

[MTX]

Correct I believe it's a 89.
Yes water pipe installed correctly

 

[flyingscott]

What about the thermostat was it replaced

 

[MTX]

Yes

 

[flyingscott]

Is the key in the impeller I think the hose is doing the work on the muffs that's why you have no flow in the lake.

 

[MTX]

Yes key installed. Could I have exhaust leak into the pump area which is forcing some water out the water intake while in lake but muffs over power it. Just kinda thinking out loud.

 

[flyingscott]

I honestly don't know it really sounds like the impeller key is not in. The exhaust shouldn't be able to get into the pump. Maybe you have a leaking fitting on the water tubes somewhere.

 

[flyingscott]

You could also have a bad impeller where the hub is spinning in the rubber you need to take it apart to see.

 

[MTX]

Thanks I'll double check the impeller.

 

[minuteman62-64]

My $0.02: I've had a number of cooling issues with my 30A and, every time but one, it was an impeller related issue. So, above advice is sound - start with the impeller.

The one time it wasn't impeller related, my motor trim was set so that at planning speed no water was getting into the intake. Are you sure that you have it set low enough in the barrel? On the water, is the intake submerged at all speeds?

 

[quicktach]

Is your water intake clean.? Did you get the blades of the impeller in the correct direction?

 

[MTX]

Pump doesn't prime. I've put in barrel started motor but no water flow. With motor running I then removed thermostat cover and stat, then used water hose to put water in stat housing area, after short while water starts to flow normally thru motor. At that point without hose, water pumps good also good stream out tell tale. However if I stop motor and restart in a few minutes, no water flow. Also, after using hose to prime with motor operating I reinstalled stat and cover, water continued to pump good. Why won't it self prime ? Any help would be appreciated. Thanks.

 

[flyingscott]

Give a pic of how deep in the water you are or the water inlet is partially plugged

 

[MTX]

Ever heard of an exhaust leak causing this type of problem ?