cooling problems 1987 force 125

dddtvlr

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Jun 19, 2008
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i just replaced the waterpumphousing,impeller,gasket and wear plate on my motor, when i put it in the water to try it out i get a spray out of the back of the motor when idling the motor is running hot when i let it idle for a few minutes,once i give it more throttle it cools back down, i have removed the thermostate and flushed it with water, no blocked ports as best i can tell,am i missing something here,thru out the years i have replaced the water pump on a yearly basis,i have checked and rechecked all my work on the pump ,is there something in the engine block that may have wear in it ??
 

JoeCrow

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Nov 1, 2007
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Re: cooling problems 1987 force 125

I wish I could help you,
I have an 86 Force 125, but my problem is opposite of yours
My motor idles fine and runs up on plane no problem, but at WOT for a few minutes, it overheats
I also replaced the impeller, housing and plate and everything is correctly aligned and installed, but at WOT after a few minutes the alarm goes off
Any ideas anyone?
Thanks
 

john from md

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Re: cooling problems 1987 force 125

The engine will run hot until the thermostat opens then it will cool down. The thermostat will regulate the temp to keep it at optimum. Have you checked to see what temp your thermostat is opening at? Thermostats are cheap to replace, engines are not.

Regards,

John
 

dddtvlr

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Re: cooling problems 1987 force 125

the thermostat was removed several years ago , this is the first time i have had problem such as this
 

john from md

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Re: cooling problems 1987 force 125

The engine was not designed to operate without a thermostat. It can't maintain proper operating temperature without one. If the temperature is swinging wildly, the aluminum gets increased stress and the fuel economy is not the best. I suggest that you replace it before operating further.

john (licensed mechanic)
 

dddtvlr

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Re: cooling problems 1987 force 125

will do that today, it was removed by a licensed mechanic about 4 years ago and he installed a temp guage on it, it normally runs well below 120 degrees even while trolling for long periods, i removed the foot again yesterday and inspected every thing again, also pressurize the water pump to validate flow thru water pump and pick up, no blockage, i then hooked up a hose to the flow tube to see if i got a good flow thru it there, i do get a good flow but it is coming out thru the exaust flow area, i removed the thermostate cover and run water through that area and i get flow thru there also, like i said before it only runs hot when idling,when i give it a little gas it cools off significantly,would ther be any type of a splash plate or pan that may be worn out in side the motor, reason i ask is that the first time i had motor rebuilt back in 1995 it ran hot when i was breaking it in so i took it to another shop and the mechanic there went back into it and said that a wash plate or splash pan or something like that wasnt replaced when it was first rebuilt and it was wore out ,but that was years ago and my memory has faded since then (guess it goes with age ) ,i mostly run it in salt water and flush it after every use, i am also trying to find a shop manual on it locally so far no luck
 

john from md

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Re: cooling problems 1987 force 125

He may have been talking about the backup plate on the water pump. It can get worn and bypass water. Usually I replace it with the pump and gasket.

The manual you can get online from outboardmanuals.com I believe. Get the Clymer it is better than the Seloc.

It is possible that your engine be running lean or is carboned up. Have you checked the compression and decarbed it reciently?

You might do a decarb and see what happens. It can't hurt.

Regards,

John
 

dddtvlr

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Re: cooling problems 1987 force 125

i have replaced the wear (backup ) plate on the waterpump, compression is good , would the exhaust plate cause a problem like this if it is worn out?
 

john from md

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Re: cooling problems 1987 force 125

I'm afraid I don't know what exhaust plate you are talking about. If there is no blockage in the system and you have good water pressure, the engine should not overheat unless it is being run lean.

Regards,

John
 

dddtvlr

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Re: cooling problems 1987 force 125

john i really appreciate your time and help, i think i am at the point of flushing the motor just to be on the safe side,and looking in to the lean mixture on carbs, compression looked good,will pull exhaust plate just to be on safe side also, hell i always wanted to go deep into one of these motor and now sounds like good time as any, again thanks for your time
 

john from md

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Re: cooling problems 1987 force 125

Any time. Please post your findings as we all learn something new from every event.

Best of luck,

John
 
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