Ive been sailing my boat pretty solid over the last year and havent had much time in marinas
. The Yanmar
3GM30F started smoking - white, but also black at high revs in reverese. The volume of the oil
increased but did not have the milky color or droplets. I discovered that the exhaust
elbow had cracked and was not poperly exhausting. After fixing that, Im now having problems with adequate water
flow in the exhaust and the engine begins heating
after running at load.
I drained the wet exhaust, replaced the impeller, tensioned the belt, verifed that the water
pump works and checked the raw water
flow all the way past the water pump.
I opened the front of the heat exchanger
and there was evident corrosion
on the inside of the front cap and inside the tubes.
I reamed the tubes out gently with a plastic covered wire. There was noticable resistance at the end, but nothing requuiring heavy preassure to get break through.
I dont know what the back looks like on these exchanger tubes and hope I didnt punch through the metal. The front cap looks like the fresh tubes are isolated from the salt
by a gasket- which is slightly corroded.
Im ready to sail another few hundered miles and wonder if Im taking teh proper approach.
1) Do I have a blown head
gasket? Ive done several oil
changes and havent seen the increase or other indications of moisture since the elbow was replaced. I havent ran the engine very long due to the wet exhasut issue.
2) Have I damaged the heat exchanger
with the ream out?
3) If tehre sia slight breakthrough on the inside of the heatexchange front cap, will this casue more problems?
Thanks for your help- Im running out of time.