225 PM heat trouble

[cmbracer]

Hi guys

It's been a while since I have posted.
Now I have a problem with my engine.
Saturday I was out boating(first real hut and sunny day this year) all of a sudden I notice my temp. gauge starts climbing, I turn my head to check the engines water outlet - STEAM is hissing out.
I emeadiatly turn of the engine, and get a tove to the ramp by a 25hp 4-stroke, passing by.

I have had the lower unit of. The pump has been opended, nothing is wrong with it. (the lower was bought new last summer, and has not clocked more than 10 hours).
The termostats has been "boiled" to check funktion, both(from the top of each cylinderbank) performes as they should. (opended at around 60 C.)
I have flushed the lower to check for blocks, water runs freely.
I have blowen air throug the water hoses on the engine, no blocks.

The only thing I can think of is the fitting(nylon) between the waterpump in the lower and the tube(metal) running down from the engine. This is not a perfect fit.

The fitting is about a 1/10 'th bigger than the tube.

This has allways been the case, and I have never had temp. problems before.

Any help would be great.

Morten

 

[FLYING BUTCHER]

LU

If you are running sportsmaster take off the inspection plate on side and look for blockage, make sure you have the rubber fitting in place where the copper hose goes into the water pump, then you will need to pull the heads and look for blockage. You probably are running a poppet valve so just remove it and check for blockage. Thats all easy if nothing there then you have blockage in the exhaust plate drain holes. It can only take a sliver of wood to block up the holes in the plate. Good luck

 

[scott mann]

overheat

Not to jump too far ahead, but I went through everything I could last summer; had the same situation. Even had two mechanics and the tri-state Mercury "guru" (Ted somebody) check my engine with all of the fancy electronic gadgets...Finally, after checking all of the things the Butcher mentioned above, I replaced all of the base gaskets (between the powerhead and adapter plate and it fixed it.
Good luck

 

[chad202]

I may have to do the same thing Scott. Mine was fine in the winter but now that summer is around, it's running 165-175. I don't know if its the gaskets or nature of the beast. A friend of mine has the same year promax as me and his runs the same temp in the summer. Our air temp is near 100 and water temp low to mid 90s.

 

[Bob Ant]

I had a similar problem. I was fishing with trolling motor and pulling my lower unit thru decayed wood layer on lake bottom. I just about completely blocked all water channels in the heads. When I noticed temp problem I immediately shut down and had to dismantel motor in order to clead all water channels. I didn't realize I was dragging motor thru garbage. Vauable lesson learned. I always trim up motor when fishing shallow waters