Old Yanmar

[NoDestination]

Recently bought a 1983 Hunter 34. Awesome boat. Sail here in Holland MI, went out for the first time last Saturday, It was freezing. The Yanmar Diesel ran fine but it does have the most hours i have ever seen on any engine. It has 1,380 hours. The surveyor said that these engines are pretty bullet proof. At what point is it time to have it rebuilt? It smokes a lot at high RPM's but otherwise starts right up and runs fine. The previous owner was meticulous about the boat so i am confident it was maintained. Any suggestions or advice or maintenance tips about this engine would be great. It is the 20 horse model.

[gc1111]

Don't know anything about your Yanmar, but 1380 hours is not a lot for a diesel.

[captbillc]

NoDestination-----by hi RPMs , what rpm do you mean? is this a yanmar 2GM20 ? what color is the smoke ? if it is black, it could be caused by a dirty air cleaner, bad injectors, or a prop with too much pitch, causing overloading of the engine. how high is the engine RPM at no load compared to full throttle in gear?

[islandhops]

only 1800 hours! That's nothing for a Yanmar 3GM. My old H34 didn't even have an engine hour meter and the Yanmar ran like a sewing machine. Just keep the oil changes frequent, replace/clean-out the mixing elbow, and check the raw water pump. She's a great little engine.

I've inheritied twin 3gm30f's that have been totally abused on an ex-charter cat. The enging hour meeters long stopped working, but I'm guessing well over 5000 hours each. They have thier moments but are still running. I'm looking at repowering and will put rebuilt 3gm30f's right back in thier place!

You've got a great engine in a great boat. Congrats.

[sailingdog]

Umm... you must not look at a lot of engines... I've seen some with over 8,000 hours on them... If the Yanmar smokes at high RPMs, something is wrong with it.

Given its age and the number of hours, my guess is that it wasn't used much, or maintained properly. If the owner had been going by the number of engine hours for his maintenance schedule, chances are that the engine did get its oil changed much more than every two years. 1380 / 26 =53.08 hours per year or so...

Chances are also likely that it wasn't run very often long enough to blow the carbon/soot out of the engine or to heat off the moisture that collects inside an engine.

I'd rather have an engine was used regularly and well-maintained than one that was barely used and maintained on a minimal schedule—which is what this one sounds like.

[Bump]

I have a 1979 2GM15, with many more hours, runs great. 1380 hours is nothing for a diesel. Maintain it well and it has many years left. FYI, I add about 60-80 hours a year which is just above your average annual running time.
By the way I spent my freshman year at Hope College in Holland. You are indeed brave to be sailing already. Has the lake ice even cleared? Remember the Titanic!

[NoDestination]

Thanks for all the replies thus far. The smoke is black not blue so it is not burning oil. It is revving at about 4,000 RPMs full tilt in gear i believe. Like i said it was the first time out and it was freezing. Next voyage i can answer more of these questions. What is the mixing elbow? and how do i clean it?

Thanks

[NoDestination]

Ya it was awesome. We spent the night out there at El Deans it got about 25 degrees. Check out our website three3degrees.web.com. Co owner still goes to hope.

[NoDestination]

sorry three3degrees.webs.com

[SteveInMD]

Smoke can have a variety of causes. It's often the result of a dirty prop and bottom. Another common cause is a prop with too much pitch. If you run up against your hull speed and try to power faster, you will get smoke. As mentioned above a clogged mixing elbow can be the cause. Buy the Yanmar parts and service manual for the engine and follow the service intervals, including the elbow and injectors. If there is no records on board of servicing these items it's time to do it. Pulling the injectors and sending them off to be rebuilt is not a difficult job. I would spend this season getting know the boat and engine, then pull the injectors next fall. If you can get to the elbow it's not hard to remove, inspect, replace it if needed. Do be careful on the re-install as you are working with a system that handles carbon monoxide! I use some exhaust system sealer between the elbow and block.