Moderated Discussion Areas
  ContinuousWave: Whaler Repairs/Mods
  Thermostat on Johnson 88 SPL

Post New Topic  Post Reply
search | FAQ | profile | register | author help

Author Topic:   Thermostat on Johnson 88 SPL
bboeri posted 08-16-2005 08:36 AM ET (US)   Profile for bboeri   Send Email to bboeri  
How do I tell if the thermostat on a 1988 Johnson 88 SPL is working correctly? Should the water exiting the telltale be warm or cold. Mine is cold. The cylinder heard also feel cold after running for awhile. I just want to make sure that the operating temp is correct. Where is the thermostat located and how do you change it? Thanks for the help.


bsmotril posted 08-16-2005 09:26 AM ET (US)     Profile for bsmotril  Send Email to bsmotril     
The thermostat is located behind an elongated cover plate on the cylinder block, centered between the heads, and low on the block inside the cowl pan. You need to remove the plastic band that covers the joint between the exhuast leg and cowl pan to be able to get a wrench up in there from the bottom.

click on the "Parts" link, follow the prompts, and you can see a diagram of the powerhead:


bsmotril posted 08-16-2005 09:28 AM ET (US)     Profile for bsmotril  Send Email to bsmotril     
When you work throught the menus to get your model, HP, and year, click on "Cylinder and Crankcase" to get an exploded view of the block with the Tstats. BillS
Buckda posted 08-16-2005 09:35 AM ET (US)     Profile for Buckda  Send Email to Buckda     
If you remove the cowling on your motor, you'll be able to determine if you can accurately guage engine operating temperature from the temperature of the confidence stream. On my 3 Cyl. 1995 70 HP Evinrude, you could NOT tell, since the cooling water was diverted as it came out of the water pump from the lower unit and simply indicated that the pump was working.

On the older mercs (no experience with the new ones) the confidence stream was only supplied with water that had already passed through the cooling jacket on the powerhead. On my Merc 150, it starts out "lake temperature" and after a hard run will actually be hot before cooling back down to "warm" as the engine is cooled off.

I don't know what the proper diagnosis/diagnostic is for checking thermostat operation, however just wanted to pass this information along re: if you could get snapshot idea of what is happening from the telltale. Generally, on OMC engines, it is simply an indicator that your pump is working.


Post New Topic  Post Reply
Hop to:

Contact Us | RETURN to ContinuousWave Top Page

Powered by: Ultimate Bulletin Board, Freeware Version 2000
Purchase our Licensed Version- which adds many more features!
© Infopop Corporation (formerly Madrona Park, Inc.), 1998 - 2000.