Rusting from water on Yanmar 3GM30F

[Bluenose from N]

Hello all, I have a Beneteau 331, with a Yanmar 3GM30F. When I start and leave the mooring all is well. But after sailing, when I push the black button, there is no sound and it will not start. I will try the button maybe three times and then it will start right up.

OK, so I took the boat to an excellent diesel mechanic. He notices that the air filter casing, the most aft injector bolt, and the starter are rusted. Water has been in contact with these on the port side of the engine. You can see in that general area of the engine that the grey paint is blistering and falling off.

It rained like hell today. My wife and I scrubbed all the topsides with soap and water in the rain and hosed them down. We went for lunch and it rained all the time. We went back and could not find any water dripping in that area.

I should mention a few years ago we replaced the external oil lines as they were corroded by water. I thought the water problem had gone away, but I now see it has not.

What do you think?

Thanks!

[gonesail]

i replaced the button on my yanmar panel .. but it could be corroded wire connections for you. sounds like it may be salt water.

[Bluenose from N]

Thanks, I have already replaced the button. I agree there is salt water getting down into the starter and that area, but where is it coming from??

[skipperpete]

Could you be getting a bit of seawater splash or spray from the siphon break valve? They often spit out a bit of raw water and are usually mounted on the engine room aft bulkhead up high.

[Bluenose from N]

Thank you for your response. I have looked at that. It faces me when I lift the steps up and look aft at the engine. It is nestled among electrical wires and insulation and I see no sign of any water there.

[chris mac]

We have the same engines. I had a small leak at the base of the sea water outlet, (to mixing elbow) there was just a little corrosion at the base of it, but all down the side of the engine had paint peeling off and the fuel hose to the pump corroded.
My mechanic told me this was a common leak point and to replace the oring.
It's an easy fix if yours is leaking. Undo the set screw at the base, lift the elbow up and you will see the oring . I have a generic oring kit and used the closest, tight, fit. It worked and took about 5 minutes
Good luck

[Bluenose from N]

Thank you ever so much for the information and the diagram!

[chris mac]

No problem, I hope it turns out to be an easy fix.
I saw your profile has you in Nova scotia. I've been cruising up here for the last couple weeks. Sitting in Shelburne right now. You have some beautiful sailing grounds!

[S/V Illusion]

Originally Posted by Bluenose from N

Thank you ever so much for the information and the diagram!

That area couldn’t be any farther away from the starter circuit if you tried.

The symptom you described about starting is almost always a result of the starter solenoid wire. A common Yanmar problem even a novice diesel mechanic knows.