Yamaha F150TXR

[Bduck]

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
    

Poppet Valve prior     Main Motor
Vinegar Flush                Vinegar Flush           Water Temp in Tub    Kicker Flush
   

Kicker Flush Tub       Poppet Port after
Temp                         Flush