1989 johnson 120hp vro"overheating"?

[ajahman]

I have a 1989 120hp Johnson outboard with VRO. The temp. gage will move from the lower Green position to the red position within 5 min. of running at 4500-5000rpm with NO over heat warning horn. The engine feels pretty warm but not hot, and the pee stream is good and strong also warm but not hot.A friend who is also my boat mechanic replaced the water pump and thermostats,still get the same results.Tested the overheat warning horn on both sides and they are working,also the S L O W system is working. Do I trust the gage or the overheat warning horn or what?Could the temp. sensor be bad in the temp. gage?Any ideas will be appreciated.
Thanks.

 

[tashasdaddy]

Re: 1989 johnson 120hp vro"overheating"?

contact a dealer and get some temp sticks. that's the best way to check it. they are like crayons, and melt at different temperatures. you place them on the block. and then run the engine. if the melt it's getting too hot.

 

[kenmyfam]

Re: 1989 johnson 120hp vro"overheating"?

contact a dealer and get some temp sticks. that's the best way to check it. they are like crayons, and melt at different temperatures. you place them on the block. and then run the engine. if the melt it's getting too hot.

Great idea. You can most likely get them at a welding / heat treatment shop or a factory suppliers for real cheap. Make sure you get temperature ranges to suit the range you need though. You may need a few of them.

 

[ajahman]

Re: 1989 johnson 120hp vro"overheating"?

Thanks for the reply guys! I'll see if I can find some of the sticks localy. Thanks again!

 

[ajahman]

Re: 1989 johnson 120hp vro"overheating"?

New question. Where do I mark the cylinders with the heat crayons? On the top or sides of the cylinders? Thanks.