Mercruiser 350/260hp - run without thermostat?

[allingeneral]

Re: Mercruiser 350/260hp - run without thermostat?

about 5 miles down from CB, just before westmoreland state park--sounds like maybe 10 miles or so from you. we're at lunch often at happy clam or

also, i don't have the specifics, but you can measure the flow of the engine by hooking it on muffs and seeing how much exhaust water you get/minute.

Ah, cool. I usually launch at Stepps (Maddox Creek) near Oak Grove. We run down to Sharktooth Island from time to time. That's a pretty neat place.

 

[Moe123]

Re: Mercruiser 350/260hp - run without thermostat?

I have a 1989 Sea Ray with a 350/260hp Mercruiser w/ Alpha One outdrive. Is there any reason that I shouldn't run it without a thermostat?
I'm having overtemp problems at idle - especially after running down the lake on plane for a few minutes, then dropping to an idle - temp quickly climbs to 220*F - which I know is way hot.
I'm going to replace the impeller/pump housing in the lower unit and see what effect that has.


Saw this older post and i had exactly the same problem, impeller did nothing.
Was the two smaller hoses from thermostat were blocked at the blue drain plugs. ( I just got the boat)
I also removed the risers and rodded them clean, new gaskets and used permatex ; runs about 110f.

My question: i installed a 140 stat on the block under the hose manifold? (about 3x6") upper stat is gone (corrosion) so my new stat seems to warm the engine not the risers? as the gauge only goes to 110. Is this something to fix or ignore? thanks