Thermostat for Atomic IV

owlmtn · #1 (**permalink**) 07-12-2005

I just saw a price of $100 for a thermostat for my atomic IV (moyer marine) there''s gotta be a better solution! is there an automotive themostat that would work. What''s so special about this particular themostat. I''d love to hear from anyone with any experience. Jim

Irwin32 · #2 (**permalink**) 07-12-2005

I am unaware of an alternative for the atomic 4 thermostat. I think you are stuck. Moyer Marine is a fair place to do business with. Just be sure your old thermostat is the problem. Have you put it in a pot of heated water, with a thermometer, and watched what it did as it approached 140 and 160?

owlmtn · #3 (**permalink**) 07-19-2005

Irwin, Yeah i put it in hot water and it''s not opening until a little over 180. it also doesn''t open completely. however it is also becoming apparent that i''ve got some constriction in the cooling system. either in the raw water or fresh water. rust or maybe an old impeller. the raw water intake is fine and the screen is clean. The engine doesn''t overheat at 1500 rpm but will start to overheat at 2000. Jim

Irwin32 · #4 (**permalink**) 07-29-2005

Moyer does say that running the A4 at 180 is a good thing and that running it at 160 is not really good for it as the cooler temperature encourages carbon buildup.

Billpjr · #5 (**permalink**) 07-29-2005

But running a raw saltwater cooled engine at temps above 140F makes buildup in the cooling passages faster. High temps are for fwc.

Irwin32 · #6 (**permalink**) 07-31-2005

That is correct, I forgot about salt water cooling - though 160 is, according to the A4 manual, the top temp for normal running. Moyer feels that boats should be converted to a self contained cooling system so the engine can run hotte

maa1994 · #7 (**permalink**) 07-06-2010

Jim,
I know this was a while back, but may I ask what your final solution was on the replacement of your thermostat. I have a 140 that appears to need replacing and is opening at about the 190+ mark. Funny thing is, I bought another Merc 140 and tested it on the stove only to find it responding in the same way.
Any help from anyone would be greatly appreciated.
Best, Miguel

SEMIJim · #8 (**permalink**) 07-07-2010

Moyer Marine sells retrofit kits that retrofit the A4's thermostat housing to accept a current-production thermostat.

Jim