Temperature of engine still not right

[Champ2005]

Thanks, I am going to do the pinch test first. I have to get those clamps you spoke about before I can do it.

Perform the pinch test when the problem occurs on the water. It's not hard to do and the results will point to the answer to your problem.

It is possible that the poppet valve is sticking, but most technicians would do the simple, no parts involved, pinch test before disassembling the poppet valve.

[EuropeanAM]

Follow the recommendations you've been provided (above) pinching off the dump hoses at idle.

I suspect you have either had a considerable amount of sand IN your thermostats, or there may be a considerable amount of sand built up in the adapter plate and cooling system passages.

Don't overthink it, it's this simple: Excellent water pressure, engine running cold. The water is going SOMEWHERE- and if it were the Poppet Valve it would likely have LOW water pressure. Thermostats are the likely problem (specifically damaged or debris laden).

[Champ2005]

Alright, I put the motor on the muffs. The temp would not go above 86 degrees. I pinched both hoses (completely shut) and the temp rose to 125. I took out t-stats. Nothing visible observed keping them open. I took all four t-stats I have, including the 2 that were installed that wouldn't come to temp and performed the "thread" test on them. Old t-stats #1: opened at 139.1, #2 opened at 141.2..both closed within 1 minute. Brand new t-stats #3: opened at 134.1, #4: opened at 136.2 and both closed within 1:07. All temps were measured using a thermapen thermometer. Pulled compressor strainer and it was clean as a whistle. Reinstalled t-stats #3 and #4 and started engine on the muffs. It reached 120 degrees at 4:10 sec, at 5:10 it was 128 and started dropping, then went back up to 128 and started dropping again. Third time on the muffs, it reached 120 degrees at 3:09. I allowed the engine to cool for 30-40 minutes before retesting each time. PSI of water pump was consistently between 4-5psi during testing. I also flushed the engine with the compressor strainer out and didn't notice much coming out of the strainer hole. Visual inspection (under magnification) of t-stats didn't show anything keeping them open. Suggestions?

Leave everything connected.
Pinch hoses completely closed.

Start the motor and run at IDLE SPEED, on muffs, or in the lake.

Watch temperatures.
IF temperature hits 130* then release the clamps, and inspect the thermostats again.

[lpugh]

Water pressure on the muffs is not at all accurate, could very well be hose pressure being read, just be aware of this
I have pulled more than stat out for testing that did no appear to be stuck, because it was less than .025, very close inspection is required. Look in your heating pan after they open for derbis that may have fell out during the process

[Champ2005]

I understand about the water pressure on the muffs. I did look at the t-stats with magnification and just couldn't see anything. I'm going to run it on the lake today and see what happens. Thanks.

Water pressure on the muffs is not at all accurate, could very well be hose pressure being read, just be aware of this
I have pulled more than stat out for testing that did no appear to be stuck, because it was less than .025, very close inspection is required. Look in your heating pan after they open for derbis that may have fell out during the process

[Savage]

The seats on the thermostats ARE damaged, IF the temperatures INCREASED, during the "pinch test"...……..OR there IS sand in the pintle, which is not allowing the sealing disc to return to a seated position (sealed off), at ambient temperatures.

[lpugh]

^^^^^^Got to agree with that
Take less leakage than I would have thought to cause a problem

[Champ2005]

I reinstalled the newer t-stats and went fishing today. Boat warmed up fine each time. Water pressure was 4-5 psi all day when idling. Hopefully, this battle is over. Thank you for helping everyone!

The seats on the thermostats ARE damaged, IF the temperatures INCREASED, during the "pinch test"...……..OR there IS sand in the pintle, which is not allowing the sealing disc to return to a seated position (sealed off), at ambient temperatures.

[Savage]