Engine temp raises when shut off engine??

[jones56]

Noticed my engine temp risies when I shut off engine... When running down lake temp is 150ish to 160ish when I shut the engine off with key on to watch temp gauge is rises to around 215-220, is this normal?? It cools down to normal when I restart the engine..

 

[Fireman431]

Re: Engine temp raises when shut off engine??

Can be normal. I haven't seen it that high on mine, but you have to remember that that engine is no longer getting cooling water circulating when you shut it down. The degree as to how high it goes would probably depend on what phase of opening the thermostat was in.

 

[scipper77]

Re: Engine temp raises when shut off engine??

Not sure if there is a problem but I would recommend letting the boat idle for a minute or two before shutting down to let the engine cool off more before you shut down the motor and water pump.

 

[45Auto]

Re: Engine temp raises when shut off engine??

It's perfectly normal. Every watercooled engine does it. The water FLOWING through the engine carries the heat away to the lake (or radiator). When you turn the engine off, the water stops flowing and the water sitting in the engine continues to absorb heat from the metal, raising the temperature of the water. It's more pronounced on a boat than a car since the boat engine is typically under a heavier load, thus generating more waste heat.

 

[ziggy]

Re: Engine temp raises when shut off engine??

i think it may be normal too. my engine also does it. after restart though, within sec. the temp. starts to drop back down. within a min. or so after restart it's back to it's normal reading.
like said above, letting it idle for a min. or two after a hard run seems to help keep the temp from going real high after shut down.
i call this phenomenon heat soak. don't know if that's the right words, but that's what i call it as the water is soaking up the heat with no where for it to dissipate to other than the surrounding air..

 

[wca_tim]

Re: Engine temp raises when shut off engine??

just takes time for the heat generated in the cylinders and exhaust gas passages to make it's way through the engine block and heads to heat the water... as others have said. note that in a car, we seldom leave the temp gauge on after we shut the car off... I wouldn't be surprised if the same sort of thing happened if we did.

 

[zx9rstv]

Re: Engine temp raises when shut off engine??

I actually have this issue with my port temp gauge when i'm running the starboard engine on muffs. The port gauge starts to rise and show over heat. But when I turn on the port ignition to acc the temp gauge goes back to cold. I think it's probably a weird grounding issue? The starboard gauge shows the correct water temp while the starboard engine is running.

 

[RogersJetboat454]

Re: Engine temp raises when shut off engine??

just takes time for the heat generated in the cylinders and exhaust gas passages to make it's way through the engine block and heads to heat the water... as others have said. note that in a car, we seldom leave the temp gauge on after we shut the car off... I wouldn't be surprised if the same sort of thing happened if we did.

It happens in cars too. If it's hot enough that the t-stat is open, once you fire the engine back up, it pulls the coolant through the radiator a drops the temp quickly.