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Mercruiser 57 overheating at tickover

S

stanstan

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"Hi

Last year I replaced th

"Hi

Last year I replaced the impeller, pick-up hose and thermostat. The problem was a kink in the pick-up pipe but did the impeller and housing while it was out the water.
When I changed the thermostat I noticed the boat ran hotter than before ( 175 now 145 before), now it has developed an overheating problem at tickover. It quickly drops back to 175 at anything over 1500 rpm.
Can anyone help?"
 
"When I changed the thermo

"When I changed the thermostat I noticed the boat ran hotter than before"

Wrong temp. T'stat installed or put in upside down; copper pellet & coil spring always point down.
 
"Many thanks, I will check tom

"Many thanks, I will check tomorrow, I'm pretty sure it's in the right way but now you have installed a small thought of doubt.
I ordered the thermostat online from a UK mercruiser company, are there different types?
The boat spends most of her time inland now and hardly gets over 2000 rpm, what should I be asking for if/when I order the replacement"
 
 
"Many thanks for your time and

"Many thanks for your time and help, I will double check the T'stat postion and housing tomorrow.
BTW, would the risers have any part in this problem. somebody told me (who knows all about engines, which is why his boat is on hard standing since the start of last year) to take the risers off and blow them out"
 
""take the risers off and

""take the risers off and blow them out"

I believe he is saying to have them cleaned by acid bath or by a radiator shop due to the internal buildup of rust inside the water passages, especially if you boat in salt water.

If you are going to do the risers then include the elbows and exhaust manifolds in the cleaning process.

If you have been boating in salt water for 5 or more years then just replace these parts.

But, check the thermostat first. Then if you still have a high temperature problem, get a thermal laser temperature gun that you point at parts on the engine to determine the actual temperature it is operating.

A rule to go by with I/O boat engine exhaust manifolds, risers and elbows is if all are working properly, you should be able to place the palm of your hand on any one part for several seconds w/o getting burned.

Make sure your belts are tight on the water circulating pump."
 
"Hi
Once again thanks for yo

"Hi
Once again thanks for your help.
I checked today, the t'stat is in the right way but on further investigation I found two plastic balls lower down on the housing, where the riser hoses connect. These were loose so i tightened them up and it seems to have resolved the problem.
However because I'm a lumbering great idiot I've managed to crack the T'stat cover.
Don't suppose you know where to get a cheap one??"
 
"[b]"I found two plastic b

""I found two plastic balls lower down on the housing, where the riser hoses connect. These were loose so i tightened them up and it seems to have resolved the problem."

Ayuh,..

Those are supposed to be Spring loaded...
If they're in Bad shape,... I think they can be bought seperately...
Or,...
Seeing that you need a part now,..
Try ebaying for the Whole T-Stat Housing..."
 
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