Good to hear you figured out what was wrong, sounds like it could have been pretty bad if you had not figured it out.
As of Oct 5 my backorder part for a new balancer is still on backorder which the date moved toward the end of Oct. However that doesn’t mean I can’t use what I have. I took my boat up to Bear L Fri 10-02, during which time I was getting the over temp alarm twice scooting across the lake which occurred above 3000rpm. The 2nd time I was able to watch my engine temp on my fishfinder thru the NMEA 2000, I’m convinced this is a useful tool to have. Specs allow for the alarm on is set to come on at 183°-194°. When I stayed under 3000rpm no alarm. Knowing my boat has been used in salt water on the west coast I decided to do the vinegar flush on both the main & kicker. Prior to the flush I removed the thermostat & poppet valve which is located on same side the thermostat is but lower. The thermostat was crusty with buildup so I soaked it overnight in some CLR. It came out clean but the surrounding frame showed signs of pitting. I’m thinking this is original t-stat. After researching sources t-stats are unavailable and backordered till then end of Oct, ya right. Then Amazon came thru saying Yamaha OEM t-stat was in stock and I can get it between Oct 8-16 delivery, unfortunately not Prime ORDERED, received shipping confirmation.
I was surprised to see the ports prior to vinegar flush not to be as bad as what I originally thought. When I did the test with thermostat it stayed in its only position as seen in pics. Normal operating range on both motors is 136°-158°. I had temp reach 200° in boiling water. I did the vinegar flush for an hour, after 30min water temp started getting hot and I continued to acid boil for another 30min. Once done I then proceeded to do a fresh water rinse for 10mins on each motor.
Thermostat & Port Thermostat T-Stat after soak T-Stat testing
https://ibb.co/BPT3F9T https://ibb.co/VtKsvjQ https://ibb.co/TkwDVBF https://ibb.co/crtFMqr
Poppet Valve prior Main Motor
Vinegar Flush Vinegar Flush Water Temp in Tub Kicker Flush
[color=#00369b][font=Comic Sans MS][i][size=large]https://ibb.co/9vsRbRJ https://ibb.co/yFbsf8Q https://ibb.co/DQcdpXN https://ibb.co/fnftPrC[/size][/i][/font][/color]
Kicker Flush Tub Poppet Port after
Temp Flush
[color=#00369b][font=Comic Sans MS][i]https://ibb.co/J3yhDtQ https://ibb.co/Q8srXpq[/i][/font][/color]
Its been close to a 1½mo since I have ordered my balancer with no further updates after 9-13-2020. However my thermostat I ordered thru Amazon(none prime) was shipped from the east coast on 10-4 and delivered 10-9 and installed immediately. Here is the image of the good & bad side by side.
[color=#00369b][size=large][font=Comic Sans MS][i]https://ibb.co/Gd3FRgC[/i][/font][/size][/color]