Low RPM Overheating

[Pakmule]

I recently purchased two SE106s for use with my Mercruiser 165s along with two install kits. When I was bringing the boat to have the drives replaced the port engine started overheating. I could not find any obvious reason so I shut down the engine and limped the rest of the way.

Now after the new drives were installed and with no thermostat in the engine as a test, the engine does not overheat at speed but will overheat very quickly at low speed.

Everything I have read leads me to think it is the impeller. I did not install the new drives and was curious to know of the new sterdrives came with a new water pump or would the installer have just reused the ones out of the old drives. If it is the latter I think I have found my problem.

Thanks in advance.

[Technical Support]

The drives have new water pumps installed. With overheating problems, it is best to check the impeller first. It does seem odd that the old pump overheated also, but it doesn't rule out the new impeller.

It could also be a sticking thermostat, and at higher speeds it is able to open because of the added pressure.

Tech Support

[Pakmule]

It was taken for a short run with the thermostat taken out, it did not overheat at speed but coming back to the dock it did. Mechanic is suggesting head gasket but I am looking for alternate (cheaper) answers. Thanks.

[Tech Support]

You can do a compression check on the motor and see if you get any abnormal readings. If the compression check is OK then you would need to inspect the impeller in the lower unit.

Tech Support