Volvo Penta MD 11C Running Hot

[Brigadoon]

Hi,

I bought Brigadoon in November 2011 and have been refurbishing her. I am now ready to launch but in a sea trial the engine is running hot. We have flushed with Barnacle buster and taken off the manifold and cleaned it. We have also replaced the impeller and thermostat - but it is still running hot.

Any suggestions?

Hello again,

A little more information about Brigadoon. It is hull #31 made in 1981. The current engine is Volvo Penta MD 11C, 23 hp. I have no information on hours or maintenance. In my latest conversation with the yard we are looking at the option of a re-power.

My question is - those of you with this vintage CD that had a Volvo Penta MD 11C and re-powered; what did you re-power with, what was your success, what are the pitfalls, how satisfied are you with your new powertrain?

Thanks in advance for your help.

[GeorgeH]

I don't know if your MD11 is similar to an MD7 but my problem was clogged passage ways in my block. To fix it I had to remove the cooling manifold and clean out the passages ways into the block. I couldn't believe how many inlets were complexly clogged up.
George Hoffman

[Steve Laume]

You covered most of the obvious possibilities. Is there a good water flow? Are you sure it is really running hot? It could be a problem with the sender or gauge. You seem to be checking all the right stuff, Steve.

[GinoDelG]

How hot is hot? Mine normally runs at about 195 F.

[Brian2]

Is it fresh water cooled via a heat exhanger? and if so, do you have enough coolant in it? Are there air bubbles so the coolant isn't circulating?

That used to be a problem for me at the start of every season. I used to have to get all the air bubbles out.