2005 Mercruiser 3.0 Running Cool? Maybe?

[countryhick]

Motor in question is a 2005 3.0 Mercruiser (SN 0W042797) with the standard open cooling system. I just got the boat a couple of months ago and have not had it in the water yet. I pulled it out and ran it on the hose for a while this weekend so that I could change the engine oil. I ran it for probably 15 minutes and the temp gauge never moved much at all. I grounded it and it does peg out, so gauge is good. I know sender could still be bad, but the thermostat housing never felt really hot to touch. I guess now I'm just asking how long should it take for the engine to heat up? I guess the next step will be pulling the thermostat to make sure it is present and not stuck open.

 

[Scott Danforth]

without load, you cant build any heat. on a hose and muffs, it may take hours to come up to temperature.

 

[fishrdan]

Was the engine warm at all, should be able to put your hand on the thermostat housing or manifold and feel heat.

In the driveway, my boat's 3.0L (Mercruiser 140HP) only gets up to 140* or so, in a couple of minutes. Never goes much past that at home. On the water it only goes to 160-165.

 

[countryhick]

It may have warmed up a little, but not very much. Just guessing, I would say it got between 100-120 maybe.

 

[countryhick]

I opened it up last night. Hard to heat up with no thermostat.

 

[Scott Danforth]

while at it, suggest you do all the impeller service and bellows replacement. only time thermostats get removed is when someone wants to hide the fact the impeller needs service

 

[countryhick]

Looks like it has been out for a while. I actually just finished changing the impeller and lower unit oil a couple weeks ago. this was the first time running it after that.