2000 Johnson 150 sensor questions

[mcarthur121]

I am trying to determine if overheating problems are coming from my temp sensors. I have removed them, one is an Airpax 9935 and the other an Airpax 9936 I can find no information online about ether one of them. The 9935 has two wires one white/black on Tan/blue. The other has only one wire that is tan/blue. Can anyone tell me how they should be tested or where I can find replacements? Thanks!

 

[Fireman431]

Re: 2000 Johnson 150 sensor questions

See if this helps. If not, at least it's a start.

www.boatpartstore.com/jande.asp?cat=horsepower&val=4

 

[Dhadley]

Re: 2000 Johnson 150 sensor questions

The one with one wire is a temp switch only. The blue trace tells at what temp it closes. The one with 2 wires is a temp switch and controls the Quick Start feature.

 

[mcarthur121]

Re: 2000 Johnson 150 sensor questions

Any way to check the sensors to make sure they are reading correctly, I cannot find replacements

 

[Dhadley]

Re: 2000 Johnson 150 sensor questions

Yep, you can check them as per the manual in hot water. There were some service bulletins out about changing heat ranges on some 60* motors. Check with a dealer to see if yours falls in the range that needs to be changed. basically the sender would close too soon and set off the horn.

 

[mcarthur121]

Re: 2000 Johnson 150 sensor questions

Thanks, Sensors checked out O.K. I am having overtemp alarm at high RPM but as soon as the S.L.O.W kicks in and RPM's drop alarm goes away withen a few seconds. Have any idea, I changed the T-stats and the water pump and impeller are less than a year old. Does a 2000 Johnson 150hp have Poppet valves or is another component the problem.

 

[Dhadley]

Re: 2000 Johnson 150 sensor questions

Like I said, I'd check with a dealer about the bulletin on changing the sensors. I don't remember which exact 60* motors were affected but you may need to change yours to a higher heat range to avoid the false warning.

A dealer will run the motor up to temp and shoot it with a thermal gun to verify actual temp. You may have scale or crud built up in the cooling passages too. That will show up on the thermal gun too.

You mentioned water pump and impeller. If the impeller was the only part changed you'll want to put in a complete kit now.