Missing thermostats

Hey guy's, I was wondering what your thoughts may be on this.

At the lake a week or so back, my temp gauge actually started working and the motor sounded different, this was after running WOT for the first time on my boat, (bought second hand 91 Sea Ray, 91 Merc 135 v6). Made me sceered.

I take her home and ordered new thermostats and Poppet valve kit, (tale tell still putting out).

Got parts, went to replace thermostats and they had been previously removed?? I was told that was a huge No-No on my motor. K, now I'm nervous, Idles at 144 degrees, which I was told was normal, but why would you totally remove the T-stat?

Engine sounds "rougher" to me, but it's out of the water so it is a bit louder. Thinking I need to do a compression test and also get it out and run on low rpm/troll speed and watch the temp.

Thought's????

t-stats only work when the engine is at idle and low rpms...As rpms increase the popits open and unrestricted water flows through the cooling system.... The t-stats keep engine temps up for better combustion at idle and less carbon buildup....145 at idle sounds about right...Your temp should drop a little when running.... They also allow the engine to warm up when first started and idle smoother... As for why someone took them out, who knows.... Maybe they thought cooler was better....

waydon,
Thanks, that is what the mechanic was trying to explain over the phone from Florida, that is easier to understand. I will give her a go at the lake and see what the temp does, I was just paranoid I had done some damage or overlooked something.

The old Poppet valve was corroded so bad as to barely open, Maybe the previous owner took the T- stats out, but neglected the Poppet?, I will never know.

Thanks again

Update:

Had the boat out twice since I replaced the parts. I think I still have a problem with the Temp sending pc, but I get a reading of around a constant 120*.

I think rebuilding the poppet valve was the cheapest easiest thing to help my cooling, the way the old one looked I'm sure it was original and was overlooked by the 2 previous owners.

If I was someone with temp problems, I would definitely at least check the Poppet Valve on an older motor. Just my

Missing thermostats is one of the dumbest things people do on an outboard. The t-stats are there to maintain a temperture in an engine so that the pistons and block both expand. By taking the t-stats out. The piston runs extremely hot and the block extremely cold. That makes the piston to cylinder wear about 500% more or basically the motor wears out 5X quicker. It also can cause the piston to burn the exhaust side of itself and cause the piston to gauld itself on the cylinder walls. Both is bad Ju-ju.

Mike, thanks for that detail. I hope it hadn't been like that for very long, but judging by the look of the pieces they left in, (top portion with seal) it has likely been awhile.

Hopefully no damage.