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Johnson 130hp Overheating issue

ScottDNH

New member
Hi everyone, this is my first post.

I have a 1996-98? 130hp Johnson outboard. Last season I purchased it to repower my 21ft Trophy after the Force it came with blew up. It was used and with that I expected some issues, had a fuel pump issue which I got resolved, but I have had an over heating problem which 2 mechanics havent been able to resolve yet. Last season the fix was to just pull the thermostats out and let the water run freely to cool the motor, and that worked fine. Talking to another mechanic we planned on rebuilding the water pump this spring and replace the thermostats. I had that done about 2 weeks ago and got the boat on the water for the first time this past weekend. Water pump seemed to be working fine, water was spitting out freely....but I noticed it was very warm. I started motoring down the lake and opened the motor up to give it a good run, within about 1 minute the overheating alarm went off and I quickly shut it down. I again pulled the thermostats out, while on the water, started it up and the water flowed out very cold and the boat worked great the rest of the day.

Any idea why these Thermostats arent openeing and doing their job? Its basically a rubber seal that should open up and let water cool the motor but it isnt working. This is the 2nd set of Thermostats....and the water pump is rebuilt. So I have no idea what it could be.

I know ive been told by multiple people just leaving the thermostats out and letting the water run freely is fine, will cause no damage and do the job...but I would rather the thing work correctly.

Thanks in advance for any advice.
-Scott
 
with the thermostats out, the motor might not run it's best. they are in there to make sure the motor is running at the right temp, did you place the thermostats in hot water and make sure they are opening? when you have the thermostat covers off, run water back down the thermostat holes into the lower unit, and see what comes out, down here we have lots of sand bars and this is how we get the sand out of the motors.( do not use high pressure on the water hose to flush out the block )
 
wrong thermostats. triple check to see if u have the correct ones in.....dont just replace them with the same ones in there
 
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