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joem
06-07-2006, 05:37 PM
I have a fully restored top to bottom including 302 engine and250 outdrive....Engine puts out 250 h.p.which is plenty for a 71 yr. old still playing with boats since 18...My problem is engine refuses to heat up guage barely moves maybe 120 or so....Engine was built professionally by Jack Boyd of Gloversville N.Y. No matter what temp thermostat i use same results...He said to block it off with a plate and drill holes starting big and going smallersame thing no heat..Tryed blocking it off completely still no rise Put a ball valve in the water intake shut it down gradually then guage reads fine but i don,t like this idea...Also engine runs fine cold but i don,t think it is very effecient this way... With all you knowligable donzi boys out there i,m looking for ideas....Thanks the oldtimer Joem.

gold-n-rod
06-07-2006, 07:07 PM
Make sure the gauge is accurate, but yes, 120* is too cold. The new ones run 150*.

:wavey:

mrfixxall
06-07-2006, 07:41 PM
I have a fully restored top to bottom including 302 engine and250 outdrive....Engine puts out 250 h.p.which is plenty for a 71 yr. old still playing with boats since 18...My problem is engine refuses to heat up guage barely moves maybe 120 or so....Engine was built professionally by Jack Boyd of Gloversville N.Y. No matter what temp thermostat i use same results...He said to block it off with a plate and drill holes starting big and going smallersame thing no heat..Tryed blocking it off completely still no rise Put a ball valve in the water intake shut it down gradually then guage reads fine but i don,t like this idea...Also engine runs fine cold but i don,t think it is very effecient this way... With all you knowligable donzi boys out there i,m looking for ideas....Thanks the oldtimer Joem.
I see this in jet boats all the time,,,you may have to restrict thewater coming out of the seapump or slow down the sea pump to keep the cool water from cooling the engine tooo fast.....but i would wait til we reach our hotter months before doing so....

MOP
06-07-2006, 09:21 PM
What type of raw water pump and how is it driven, crank or belt at what speed compared to engine RPM? Also where are you putting the water into the engine, at the Tstat housing or at the circ pump? If you feed it at the circ pump it will push the Tstat open, though with you trying a restrictor plate that should not be an issue.

Phil

David Ochs
06-08-2006, 08:31 AM
Joem,
I appreciate your concern. I assume that my 1969 302 is set up the same as your's. It does exactly the same thing. I've thought of ways very similar to what you have described to allow the thermostat to do its job. I've concluded that there really is no safe method without converting to a system with a heat exchanger and circulating pump.
I've also made the realization that the motor in my boat is 37 years old and still doing well, leave it alone!

joem
06-08-2006, 03:46 PM
Your right if sometiing isen,t broke don,t fix it....Joe