Cooling/heating problem

pep

Recruit
Joined
Feb 18, 2012
Messages
2
I have a 2000 250 hp Johnson Model J250VXSSS which never gets up to temp. The temp gage on the dash works, I have grounded out the wire to the thermister and the gage pegs max. The boat is operated in Florida salt water so the water typically is warm. The temp gage never gets off the lower peg. The lowest temp on the gage is 120 F but it never gets up to here.

I suspect the thermostats have been removed but I do not know where they are located. Does anyone have a picture of the thermostat tops so that I can identify them? I have worked on planes, cars, etc. but no boats. So I am new at this.

You can email info also to paulprice6790@comcast.net.

Thanks.
 

daselbee

Commander
Joined
Jan 20, 2009
Messages
2,765
Re: Cooling/heating problem

The thermos are located at the top of each head. There is a roughly square cover held on with 4 bolts, and a hose going to the center of the cover. Very easy to check this, you will probably not even need gaskets.
 

pep

Recruit
Joined
Feb 18, 2012
Messages
2
Re: Cooling/heating problem

The thermos are located at the top of each head. There is a roughly square cover held on with 4 bolts, and a hose going to the center of the cover. Very easy to check this, you will probably not even need gaskets.

Hey thanks Das

There are two square caps with 4 bolts each. There is also one oval shaped cap with two bolts. I could not tell which caps covered the thermostats. I did not want to take something loose that I did not know what it was.

I was also told by a dealer that one of the thermostats was on the bottom where you could not see it and it was a real job to take it out. From this, I thought the oval cap was the one.

It is good news to hear that the square ones house the thermostats they are easy to access.
 

daselbee

Commander
Joined
Jan 20, 2009
Messages
2,765
Re: Cooling/heating problem

The oval one, with two bolts, kinda off-center between the two thermos, is the poppet valve. Pressure relief valve is another term for it.
Make sure that is in there too. Be careful if disassembling that one because it has a rubber grommet in there that most ppl install backwards.....look carefully at the rubber grommet and note which way it goes back. Alternately, it has very small writing on it that says "To cylinder head" (I think), that will help you assemble it correctly.
 
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