Water temp rising and falling
09-10-2007, 05:38 PM
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Water temp rising and falling
Broke in a new 498 blower motor today with a Bravo One with no ciculating pump, a crossover, and new impeller in the raw water pump. Timing, fuel ratio, oil, fluids, all look good. Here is my issue. I run a Merc 140 degree thermostat, same as I did on the last setup which was the same motor except for the heads and a few cubic inches. Now the temp goes from 150 to 200 and back to 150 in about 15 seconds. It then stays at 150 for about 5 minutes and then starts the process all over again. Thermostat? Sender?
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Last edited by ghittner; 09-10-2007 at 08:09 PM. Reason: clarity
09-10-2007, 08:43 PM
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Sorry, I missed it in your first sentence. (It's been a long day.)
Make sure someone didn't put the thermostat in upside-down.
Don't laugh, it happens!
Thermostat could be defective. Try another one.
Make sure someone didn't put the thermostat in upside-down.
Don't laugh, it happens!
Thermostat could be defective. Try another one.
09-11-2007, 02:30 PM
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does the t-stait have three small holes drilled in the outer plate?these holes i am told are there to help keep the engine up to temp and at a constant rate.
09-11-2007, 03:52 PM
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No, it does not have the holes. It is a stock Merc thermostat came withoiut them and my last one had no holes either.
09-13-2007, 07:02 AM
#10
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ghittner,
The holes are suppose to be there to eliminate this particular problem. When I bought a Stainless Marine cross over 15yrs ago.. the holes were there. I am still running that stat today. I havent seen it in a long time, but they are 1/8" I think.. Try drilling three evenly spaced holes in the flange. If it helps, but doenst cure it.. drill them to 3/16"... that should do it.!!
Or call Stainless and see what they recommend..
Hope this helps.
D*ck
The holes are suppose to be there to eliminate this particular problem. When I bought a Stainless Marine cross over 15yrs ago.. the holes were there. I am still running that stat today. I havent seen it in a long time, but they are 1/8" I think.. Try drilling three evenly spaced holes in the flange. If it helps, but doenst cure it.. drill them to 3/16"... that should do it.!!
Or call Stainless and see what they recommend..
Hope this helps.
D*ck
