'89 Force 125 H.P. too hot at idle

[Fouled Plug]

You can't judge an impeller by looks alone. If it's the original one you must replace it. The vanes take a set and lose efficiency. They should be replaced every 2 years, or more often if you do a lot of boating.

 

[doggies3]

'89 Force 125 H.P. too hot at idle

My '89 Force 125 H.P. has been great all these years, but has started to run hot and sound the buzzer after idling / trolling for 5 min. or so. I figured the impeller was gone having never been changed, but it was perfect.<br />Some water spits out the top exhaust holes which I think shows water is pumping, but it has now pretty much turned to steam even on a warm day.<br />Thermostat? Pressure or ??? valve? Where is the thermostat on this motor. <br />Any help would be appreciated, thanks.

 

[jrbpit1]

Re: '89 Force 125 H.P. too hot at idle

Do a compression check also. I had a similar problem to this on a 75hp Chrysler. It turned out to be a blown head gasket.

 

[doggies3]

Re: '89 Force 125 H.P. too hot at idle

Thanks for the info guys. Last night I removed the thermostat, flushed the motor out, tested the 'stat for 130 degree opening (OK) and put it back together. All cylinders test 140 or so on compression. Ran it with the muffs on and STILL getting steam (with a little hot water) out the top ports. As son as I increase the idle it cools down and seems O.K. I will try replacing the impeller even though it looks good (if I can find the right one) and the thermostat and see what happens. Any other suggestions? Thanks again, CA Dave

 

[doggies3]

Re: '89 Force 125 H.P. too hot at idle

One more thing - I would like to install a temp gauge so I can see what's going on. There is a small brass threaded plug on the top of the t-stat housing that looks like it is designed for this? Or do you hook it to the orange temp sensor wire already coming out of the head? Any idea's where to get the right one? Thanks.

 

[ODDD1]

Re: '89 Force 125 H.P. too hot at idle

CA did you look at the impeller housing last time you had it apart? these housings dont have a stainless sleeve in them and DO wear badly...if the housing is shot, even a new impeller wont help....your guage question, use the hole in the top of the therm housing..the orn temp wire is an on or off thing ,for a light or a buzzer....the right one can be had at your local merc dealer...

 

[doggies3]

Re: '89 Force 125 H.P. too hot at idle

Many thanks to all for the info - this "forum" is very helpful. I will report back on the results soon.