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Tag: maintenance Page 1 of 2

Motor parts degreasing day

While I have the Yanmar 3GMD motor out of the boat I want to knock off the rust that is slowly creeping in. The paint on the motor is starting to fail, which makes sense after 34+ years of service.

Today I spent a few hours and 10 canisters of brake cleaner getting the build up oil and carbon off the external parts of the motor. There is still quite a bit more left to do but this was a good start.

I only took one picture, but see how much better the transmission looks?!

Motor disassembly and issue finding

Harold, a retired diesel mechanic who has generously donated his shop and knowledge, and I ripped into the motor today. What we found was both better and worse than anticipated.

The Good: All the major internals seem to be in fine condition. The issues seem to be limited to the piston.

The Bad…

We initially thought cylinder 2 had a stuck ring. We pulled that piston out first and sure enough, stuck rings. Stuck pretty good too. Barely a gap in the rings and no movement from them whatsoever. Then we popped out the cylinder 3 piston, whoops stuck rings on this one too! Worse than the first! The rings were stuck in so bad they had to be pried out. There was significant carbon build up in the grooves the rings fit into. Harold showed me a neat trick to use and end of the ring to scoop out the carbon. Made quick work of that.

That was not the extent of the issues though. The bearings and rods looked great. No discoloration on the piston or cylinder sleeve that would indicate overheating or worse. No grooving. However after we cleaned off the piston heads Harold was examining one and found a nasty crack that runs nearly through it, another had a crack forming. I am going to be replacing all three pistons and their rings just to be on the safe side. Because everything else looks so good I will have full confidence in this motor when we get it back into the boat.

While the motor is out I want to get the rust cleaned up and put new engine paint on for protection. That is the next actionable step.

Pulling the engine for a rebuild

In the last post I mentioned that cylinder 2 was having some blowby issues. I took the head in for testing in the hopes that it was cracked and the issue. The head came back superbly. That meant it was time to dig deeper into the motor, which meant pulling it and putting it up on a bench at Harold’s house.

Today I pulled the motor with the assistance of Shane and AJ. Both great guys. It went remarkably smooth. I anticipated it taking a few hours but it wound up being less than an hour. I had everything prepped and disconnected when my helpers arrived though which certainly helped.

Tomorrow I will be heading out to Harold’s shop to put it on a bench and start pulling it apart to see what is what.

Reminder to change fuel filters often

Billabong’s Yanmar 3gm is having a hard time firing. I am fairly certain it is due to fuel issues. When I pulled out the primary and secondary fuel filters there was a lot of gunk that came out with it. Clogged fuel filters restrict fuel flow and can cause issue inside the motor if not changed out. Based on what these filters look like I believe it is also time to suck out and polish the fuel tank as well. After changing the filters and trying to fire the motor out of a fresh can of diesel I am concerned the injectors and/or injector pump is also clogged up due to filter failure. Waiting on a real mechanic to come provide his opinion on the matter.

(Click images to make them larger)

This is the primary filter. It came out looking like mud with thick brown sludge oozing out. The fuel has an unhealthy look about it as well.


This is the secondary filter. It does not look muddy but there are big concerning chunks that nearly completely clogged the filter material and were swirling around inside the filter housing.

Sink rust be gone!

Billabong has primarily been used for racing over the past couple years. That means some things in the cabin have been accidentally neglected, like the sink. It had a few rusty spots in it. Luckily I learned about Krud Kutter recently while cleaning the dinghy and a kayak. Krud Kutter again proved its worth by cleaning out the rust an making the galley sink nice and shiny again.

Sink rust be gone!

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