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How hot should the block get on a 150 EFI?

A

Airchair

Member
Hi guys, I have a 2006 150 EFI. I had an overheat alarm a few week ends back. There was water coming from the tell tale. The block was so hot that I could not even hold my hand on it for a second. I changed the impeller and the overheat warning alarm does not come on anymore. After I took the boat out of the water yesterday, I took off the cowling, and the block is still very warm, not as hot as it was before I changed the impeller , but hot enough that if I hold my hand on it for more than a few seconds I get burned. Is this normal? I don't know if the block would be cooler if the motor is running, as I had already taken the boat out the water. Before I took it out it has been running for around 2 hours with no overheat alarm. Just wondering how hot the block should be once the motor has been turned off for around 20 minutes. Regards Greg
 
The block will be too hot to hold your hand on for more than 5 seconds while running.
It will be hotter after10 minutes or so due to heat sink.

I would say you motor is normal
 
magnum19 said:
The block will be too hot to hold your hand on for more than 5 seconds while running.
It will be hotter after10 minutes or so due to heat sink.

I would say you motor is normal
Click to expand...

Thanks Magnum, ran fine for around 2 hours with no overheat alarm so I assume all is well, thanks for your reply.
 
Typically the thermostat will be somewhere in the 140-165 degree range.

The overheat alarm will go off if the temp reaches 190 and will stay on until the block cools down to 170.

So as long as the alarm isn't going off it should be somewhat south of 190 degrees - which is still pretty darn hot.

If you are still concerned you can get a IR thermometer in the discount auto places for under 20 bucks now and they work well enough to ease your mind :)
 
Hi Greg. You don't say what year the motor is, but I would believe this a V6 motor. I'm running a 91 V6 200 HP and had a very similar thing a few weeks back. Only got the overheat buzzer once but the thing ran so hot the whole weekend I was really worried. Tell tale also runs so hot that you can't hold your hand under for more than few seconds without serious discomfort.

Had the impeller and water pump gaskets replaced as well as the thermostats and poppet valve checked and the mechanic flushed the whole system with no apparent blockages showing up. All now good but the thing still runs very hot (Can hardly make a 3 - 4 Count with hands on the heads after running for a while), but according to the mechanic these motors run hot and always will.

Just make sure that you always hear the beeps when you turn the ignition key on, which is somewhat of a confirmation that the warning horn is working. Some guys would recommend a water pressure gauge, I have a temp gauge and am learning what "normal" temps look like when running
 
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