Johnson 1991 50hp VPRO Heat Alarm

[bubbless]

I have a pontoon with a 1991 50hp Johnson that randomly sounds the heat alarm. I have water coming out of the pisser tube and it is warm not hot. I had the Marina look at the engine and they said everything looks fine but I should mix my gas along with the oil that it is pumping. I mixed the gas at 50:1 and had no problems all weekend. Today I get the overheat alarm after 10 minutes at low rpms. Any ideas? Is there a thermostat in these like a car that could be failing?<br /><br />Thanks,

 

[Cricket Too]

Re: Johnson 1991 50hp VPRO Heat Alarm

Have you checked the oil in the resevoir? Maybe it's sounding the overheat alarm for low oil.

 

[bubbless]

Re: Johnson 1991 50hp VPRO Heat Alarm

It is about half full. I thought the oil buzzer was a pulsating alarm and not a constant alarm. Do you know if the fact that this is a constant alarm means heat or oil?

 

[Brew2]

Re: Johnson 1991 50hp VPRO Heat Alarm

Yes there is a thermostat.<br /><br />If you go to the evinrude.com website, look under engine diagrams, choose "Johnson" at the top of the page, input your year/hp, and choose "cylinder and crankcase" from the menu, you'll find a diagram including the thermostat.<br /><br />Cheers.

 

[Brew2]

Re: Johnson 1991 50hp VPRO Heat Alarm

Oh, and I believe you are correct...the constant horn is the overheat alarm, not the low oil warning. Hopefully someone will come along and confirm that for you.<br /><br />Cheers.