T Stats
 

I just replaced mine. After it warmed up it idles better than ever. After 15 minutes or so on the muffs you can still stick your hand on top of the head for about 30 seconds or so. Monday I'll take it for a ride to be sure but I'm confident that was the problem..........

I know some of teh go fast guys use nickles(or maybee its quarters), drilled out in the middle to offer some restriction in plae of thermostats.

But getting back to the original post, I don't think your engine had any type of rpm restriction in case of over heat, sorry to be the buzz kill, but if it reduced rpm's, it may be something else, you might want to do a compresion test

What happened I was going in to the buoys for the channel to get under the bridge I slowed down from 4400rpm or so to about 3000rpm for about 5 minutes of so when it happened ,I when to neutral then back in gear and it shut off and never came back on.........

You made me nervous about the motor that maybe a piston was melting down, so I did a compression test and everything was 118-120 psi same as before.........

your poppet valve opens around 2500 rpms or so. it lets more water in the powerhead above that speed. if you run your motor just below the speed that it opens your motor will run hot. if you have a water pressure guage you can watch as you slowly accelerate the pressure increases than drops(poppet opens) than increases again. long story short... you may need to replace the water pump. Merc pressure style water pumps like yours should be changed every other year. they are cheap enough and very easy to replace.

A water pressure guage goes a long way to keep your eye on the condition of your motor's cooling system. one of the best investments I ever added to mine!!

:nice:

T Stats
 

Just got back from a 1 hour run around the lake. NO MORE ALARM...Thanks for the help......

Can anyone tell me if an 84 90hp inline would have t-stats and if they do where would they be located?

Turbo