Engine Overheating

Perithead · #1 (**permalink**) 03-03-2008

Went down to the boat this weekend and had a great sail Friday and Saturday. Both days I motored in and out of my slip with no over heating alarm coming on.

Sunday morning before going out again, I decided to clean the in line filter for the raw water pump (I believe that is the name for it). So I took it out and cleaned it like have done before and stuck it back in. Started motoring out and after a few minutes the warning light and buzzer came on for high temperature. I killed the engin, raised the sails, and then rechecked my work. Ah-ha forgot to open the seacock after I was done. So I figured I solved my problem.

We sailed all day long and then when it was time to come in I fired her up and after a few minuties the alarm come back on. I quickly shut it off and raised sails and sailed around for a bit, letting the engine cool. Again I check my work; opened and closed seacock a couple times, and took the filter out again and cleaned it and put it back in. Then sailed most of way to my slip and cranked the engine at the last moment and slipped her fast enough for the buzzer not to sound.

I left the boat quickly without looking at it and now I wonder what it was that went wrong? Anyone?

The engine is a 16h Yanmar

sailingdog · #2 (**permalink**) 03-03-2008

When was the last time you checked the impeller. If it has been a while, chances are good that the impeller may have thrown a blade or two.

chucklesR · #3 (**permalink**) 03-03-2008

Air pocket/ or air lock in the raw water line.
Check the impeller - replace if bad. I'll bet it's dry. Use what ever you have to and pour water into the line/pump until it comes out at the strainer.

T37Chef · #4 (**permalink**) 03-03-2008

You may have an "air pocket", has happened to me before, or so I think thats what it was.

If its persist, it could be your heat exchanger. You can start by cleaning it out by removing the end of it. If no success, run a chemical treatment through it...I used Barnacle Buster with great success. If that doesn't work you may need to remove the exchanger and send it to a radiator shop for a cleaning.

TRAC Ecological Marine Products

T37Chef · #5 (**permalink**) 03-03-2008

chuckles, you beat me to it

Perithead · #6 (**permalink**) 03-03-2008

Yeah, I was thinking I should replace the impeller and might so this next weekend. I am a new owner and I dont know if the PO knew much about it so it sounds like something I want to do.

How much is an empeller? How tough is the job?

If there is an air lock of air pocket in the line, how do I go about fixing that?

chucklesR · #7 (**permalink**) 03-03-2008

Quote:

Originally Posted by T37Chef

chuckles, you beat me to it

I've been taking robo typing lessons from SailDog.

chucklesR · #8 (**permalink**) 03-03-2008

Quote:

Originally Posted by Perithead

Yeah, I was thinking I should replace the impeller and might so this next weekend. I am a new owner and I dont know if the PO knew much about it so it sounds like something I want to do.

How much is an empeller? How tough is the job?

If there is an air lock of air pocket in the line, how do I go about fixing that?

Pour or suck water up the line using what ever works best - get water to the impeller before you close the system by putting the cover on.
Edit -
Added how to:

Look for a manual for your boats engine, it should detail the procedure. New impeller should run less than 30 bucks, take about a hour.
If there is no manual - look for the water pump - follow the hoses to the roundish housing that has a engine drive belt and a pulley wheel. It should have screws holding it on. Remove screws - but not unless you have a replacement impeller and gasket. Pull out the old impeller using a hooked wire, needle nose pliers and certain swedish curse words. Wet the new one, put it in. It's a pain, but it will fit.
Put on gasket, put suck water (a clear hose and a lot of lung) until water comes into the housing.
Put on cover.
Drink Beer, or Rum, feel proud. Go sailing.

p.s. if you are real lucky, these guys make one for your engine : Sailboat Parts Search for speedseal in the Torresen Marine, Inc. Online Sailing Ships Store

10 minute impeller changes

I have one on my Westerbeake 30b

tjaldur · #9 (**permalink**) 03-03-2008

Most impeller pumps should not be allowed to run dry. It may be that you let it run dry long enough to damage the impeller. Also check if the filter sucks false air after the cleaning.

Perithead · #10 (**permalink**) 03-03-2008

"Most impeller pumps should not be allowed to run dry."

Would running the engine with the seacock closed be considered running it dry?