'86 Yamaha 90 - Tstat replacement DIY?

[Casco Bay Outrage]

After lurking, here is my first post.<br /><br />I have done a search here and don't seem to see the answer.<br /><br />I have a '86 Yamaha 90 2s that has been great. Replaced water pump several weeks ago. Tell tale is strong. <br /><br />Now when the boat runs 3k or higher, get an overheat alarm (steady tone). At lower speeds, alarm stops.<br /><br />Boat is trailered but is used in salt water and flushed.<br /><br />I reviewed Yamaha parts diagram online. T-stat removal/replacement appears to be very straight forward. Is it straight forward?<br /><br />Should I replace the gasket, spring, valve and grommet or just t-stat?<br /><br />Thanks!

 

[bayhawk14]

Re: '86 Yamaha 90 - Tstat replacement DIY?

Might as well change all, not that expensive. I'm having the same problems you described with mine right now & the heads are being pulled and cleaned. I hear that Suzuki's & Yamaha's do not handle corrosion or scaling build up very well. Probably want to check compression as well, hopefully your buzzer did the job.

 

[rodbolt]

Re: '86 Yamaha 90 - Tstat replacement DIY?

if the bolts come out its easy, clean the pressure valve pocket carefully and install a new grommet.<br /> if the problem persists odds are high the next step is head removal for cleaning.<br /> its all in how many bolts you break.

 

[Casco Bay Outrage]

Re: '86 Yamaha 90 - Tstat replacement DIY?

Rodbolt - <br /><br />What would you use to clean the valve pocket? Are the chances of a broken bolt pretty good?