Overheating Renault

[Dan Bryant]

While motoring back to port this weekend in my '80 H27, my 8HP Renault diesel seemed to be running hot. Unlike any other times when this happened, none of my standard remedies seemed to cure it. I checked the seawater intake, replaced the impellar, checked the hoses, and even got in the water and monitored the cooling water exiting the exhaust (which seemed a little warm, but not bad). The problem only happens near full throttle; it will run for hours at half thottle but when I peg it it the gauges reads hot nearly instantaniously.Any suggestions?

 

[Bob Heaslet]

clean mixing elbow

I solved a similar problem by removing the exhaust elbow from the cylinder head (two 5/8" nuts) and exhaust hose. Use a screwdriver or ice pick to scrape out the coke buildup. Be sure the water inlet pipe is clear and open. I restalled the exhaust elbow with high temp silicone and it worked fine.

 

[John Noland]

plugged through hull

Had the same symptom twice now on my 83 H31, and it turned out both times to be seaweed caught in the through-hull fitting. Another clue was the water hose feeding to the engine was trying to collapse, a sure hint of a clogged hose somewhere on the water intake side. I made the repair both times by 1) closing the through-hull valve. 2)disconnect hose at strainer, and point straight up. 3) Cut and straighten metal coat hanger and poke down the straightened hose until the valve. 4) Open valve briefly, ram wire down and through open valve. 5) Remove wire, then blow down hose (you should hear air bubbles outside hull) 6) Close valve and re-attach hose (double check, two clamps. That stopped the over-heating.

 

[Bob]

Water Temp?

We run red hot July and August and run fine the rest of the season. Where are you sailing and what is the ambient water temp? I agree that it could be soft growth on the thruhull this late in the season or the like but maybe the cooling water is just too warm....

 

[web4u2@bellatlantic.net]

Bad hose

Had the same problem a number of years ago.....turns out that one of the smaller hoses(near impellar) providing water was building up minerals on the inside and reducing the water flow needed at high revs( hose looked fine on outside), once fixed everything was fine............cheersRik