Al, I had a similar problem on a 3qm30 where it would overheat at anything above 1400 rpm. (normal cruise rpm was 2400). Here are somethings to check. How is the water flow out the exhaust, is it less than normal? Is the heat exchanger plugged or partially plugged. If you think you may have blown a head gasket, check the oil. Is it chocolate milk color? Is your engine fresh water cooled? if it is a blown head gasket may blow bubbles into the cooling system. If I have missed I am sure someone will chime in. Good luck Doug
On Mon, Jul 20, 2020 at 7:45 PM Al Serrato via CnC-List < [email protected]> wrote: > I had an unusual experience yesterday and am looking for any ideas on next > steps. > > I have a Yanmar 3GMD in my ‘81 C&C 34. I had used the motor for about 20 > minutes going out with no problems, but after starting it in heavy winds, > it rather quickly quit on me and would not start. I was heeling when I > started it and the tank was half full, so I bled the line thinking that > some air had gotten in, and it started right up. > > It ran for about 10 minutes and everything seemed normal although I > thought it sounded a little different. I couldn’t put my finger on what it > was that was different, and thought maybe it was my imagination but then > the high temp alarm went off and the gauge showed probably around 180. (It > normally runs at about 130). I shut it down and ended up getting a tow back > in. The raw water strainer was clean so I thought maybe the impeller might > have failed, since it’s close to two years old. But when I opened the pump, > it was fine. I replaced it with a new one anyway and ran the engine for 45 > minutes today at the dock, under load, and it ran fine. > > I always have white smoke coming out of the exhaust when I’m revving past > 1800 or so, but I don’t know if what I saw today was more than usual. The > engine was clean, no drips or leaks, no smells inside, just the usual smoke > from the exhaust. > > I couldn’t figure out why both the fuel and the raw water, which seem > unrelated, would both have problems at the same time, so I thought maybe it > was a blown head gasket or something like that. I figured when I started it > today, it would probably overheat right away again...but it didn’t. > > Any similar experiences or ideas on what it might be? I’ve got a call into > the mechanic but haven’t heard back yet. > > Thanks in advance. > > Al Serrato > Senza Fine > San Francisco Bay > > > Sent from my iPad > > _______________________________________________ > > Thanks everyone for supporting this list with your contributions. Each > and every one is greatly appreciated. If you want to support the list - > use PayPal to send contribution -- https://www.paypal.me/stumurray > > -- Douglas Mountjoy 253-208-1412 Port Orchard YC, WA Rebecca Leah C&C LandFall 39
_______________________________________________ Thanks everyone for supporting this list with your contributions. Each and every one is greatly appreciated. If you want to support the list - use PayPal to send contribution -- https://www.paypal.me/stumurray
