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87 30 OMC TSTAT STICKING

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skatercat68

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I have an 87 3.0 cobra that wa

I have an 87 3.0 cobra that was overheating so the first thing tht i did was check the t-stat. it seemed to be stuck shut so i just took it out. Should I run my boat without a t-stat or is it real imortant?
 
"also, I just bought this boat

"also, I just bought this boat and I had to rewire all of the gauges. I can not find the oil pressure sending unit. can anyone tell me or better yet, send me a picture???"
 
"You should always run with a

"You should always run with a t-stat in there, the engine won't come up to normal operating temp otherwise which is not good for the engine and affects fuel efficiency as well.

See item # 49 in the parts pic below should be near the rear of the engine on the starboard side, fairly large cannister with a (brown or tan) wire attached on top.

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"
 
"thanks for the diagram for th

"thanks for the diagram for the oil pressure sending unit. Very helpful!!! as for the overheating, I thinnk i need a new impeller. When i put the muffs on, i only get a little bit of water out of the water inlet hose to the t-stat, not a whole bunch. Aslo, when i hook the garden hose up directly to the t-stat everything cycles fine and the motor stays cool. I did notice however that my exhaust bellow on the under side of my foot was where 90% of the water was coming out. Again, is it important that it be solid or can i just leave it????"
 
"The newer exhaust bellows act

"The newer exhaust bellows actually has slits cut into it going across. This is to help relieve backpressure at low idle so yes most of the water will exit there, nothing to worry about. It does sound like you might need a new impeller, when removing the old one check to see if any of the blades (rubber vanes) are missing as they can get caught anywhere downstream in the cooling system and cause a blockage."
 
ok i put a new impeller in and

ok i put a new impeller in and hooked the muffs up and it worked great. Then I put it in the water and nothing. there was no flow untill I turned the motor on with the muffs so I dont get it!!! Why would it work great with the muffs and not in the water
 
The positive pressure in your

The positive pressure in your garden hose might be overcoming an obstruction or leak in the cooling system. Try to obtain a good cooling system diagram and double check everything.
 
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