Re: Runnin hot...bah!
 

I was hoping this was the case but the HIGH pressure I think says I do have a cooling problem.

Re: Runnin hot...bah!
 

tinman...i have the exact same problem.....so far..new thermostats & temp sensors,rebuilt carbs, tonight i'm changing to a complete new water pump...which i doubt will fix it since the one i pulled off was damn near brand new.....next is water circulation for me..

i can run it all day long at 35mph...once i hit 40mph/5000rpms...my overheat alarm comes on......when i touch the heads its cool i can hold my hands on both...water is pumping strong and steady at idle and high speed......think i'm gonna buy a infared thermometer next too........i really hate to start tearing into this thing....maybe i'll just go fishing and say hell with it .. just dont go over 35mph lol

Re: Runnin hot...bah!
 

if the heads are cool, i'd make sure that it is indeed overheating, the sensor for the temp is located in the head, while it is posible for it to overheat in a small area( around the sensor) its unlikely to happen, it could be cooling off before you get the boat off plane and get back to the powerhead to check it. Try this, disconect the sensor wire to the temp alarm( tan/blue stripe I think) run the engine again and see if the alarm goes off again, if it does, and your sure you disconected the over heat sensor, then you've got something else going on

Re: Runnin hot...bah!
 

Tin - did you do a compression test yet? What do your plugs look like?

Re: Runnin hot...bah!
 

BS, not yet, hopefully tomorrow (thur.) afternoon. At this point I'm hoping it's a head gasket :-/

If compression is good, before I remove the powerhead I am going to drop the lower unit, remove t-stats and poppet, hook a hose up to the water tube and see if I can flush it out.....sound like a good idea? I figured I could check the waterpump housing too, maybe it's cracked or has a leak and I'm sucking air??? That would cause a crazy psi reading, wouldn't it?

Re: Runnin hot...bah!
 

Kajun, is your pressure high too?

Re: Runnin hot...bah!
 

What if I was to remove the poppet completely? Will that cause low RPM overheat? I would think it would definately lower the pressure.

Actually, I think that would cause the motor NOT geting up to operating temp at low speed.

Re: Runnin hot...bah!
 

tin...i dont have a pressure gauge or a temp gauge...definetly on the "to do list"

Re: Runnin hot...bah!
 

Compression is good, 120-125 psi all across.....all 6 plugs looks the same, a little black oily residue.....probably some carbon left over from Seafoam procedure.

Next step is to drop the lower unit (again) and have a look-see.

Pretty soon and MJ will have more hair than me! :o :-/

Re: Runnin hot...bah!
 

Thats good though right Tin, if the head gaskets or something else similar were going bad you would not get that good compression. Right ???