Yanmar - engine rusting causing start problems

[Bluenose]

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 oillines 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?

 

[dlochner]

There is a known problem with Yammer engines. The wire connecting the solenoid to the start button is too small. When the battery is depleted nothing happens. After sever pushes, it starts. There are several fixes to this, all basically replace the wire with a heavier gauge and the problem goes away.

My guess is when you start the engine at the dock, the battery is fully charged and maybe the boat is still plugged into shore power. After sailing the battery is partially depleted and no longer has the power to quickly start the engine. This would especially be the case if the batteries are several years old.

 

[shemandr]

Drop that rating of an "excellent diesel mechanic" to an OK diesel mechanic. This is a common problem and well known.
The rusting could be from your water jacket leaking salt water on the engine. More likely than rain.

 

[Don S/V ILLusion]

Drop that rating of an "excellent diesel mechanic" to an OK diesel mechanic. This is a common problem and well known.
The rusting could be from your water jacket leaking salt water on the engine. More likely than rain.

“Excellent” diesel mechanics are very aware of the start relay wire problem. Even “OK” ones know it. That leaves….

 

[Ralph Johnstone]

OK, so I took the boat to an excellent diesel mechanic.

Hard to believe he didn't know anything about the starting problem with Yanmar. Maybe he's never heard of Yanmar either. Out of curiosity, did he have ANY ideas as to why your engine had problems starting other than a bit of rust here and there ?

As far as a solution to your problem, this is the one I chose as simple, cheap, and most reliable :

 

[Ralph Johnstone]

You can see in that general area of the engine that the grey paint is blistering and falling off.

Can you post your picture so we can get some possible idea of the source of the water.

 

[RoyS]

Another place to look is the existing starter solenoid start wire connection. Some Yanmars have a push on stakon here instead of a stud and ring terminal. That push on stakon can become loose.

 

[jviss]

topsides

Just a nit: you washed the decks, I think. "Topsides" is the side of the boat, from the bootstripe (waterline) to the gunwhale (top edge of hull).

 

[BigEasy]

Sounds like an electrical problem, not related to water & resultant rust formation. Need to check starter circuits including, start button, start solenoid, & wiring. Also check battery charge, connections, cables, any fuses / solenoids in the circuit. During my boat search, a guy in Georgia told me that he had a corrosion problem, on his 331, with the grounding cable where it grounded to engine block, causing engine to not start. He cleaned up the connection & problem solved.

 

[jibes138]

Check the connections at the switch, and the starter. Corrosion in either place can be cleaned up with a little Emory paper and then coat the connection with a little dielectric grease to prevent further corrosion. Also check your batter cables and engine ground as previously noted. Clean them up and see if it helps.

 

[Techstyle]

Like others have said this problem is well documented and easily fixed. you can start by cleaning all contacts but ultimately you really want to either install an additional relay like others have said/done, or upsize and upgrade the red wire and the white wire that go to and from the button and key switch to the starter motor. I did a Youtube video on what I did here:

 

[Ken13559]

Quick fix to Yanmar engine starting issue is the cable loom connectors. Clean the contacts with Contact Cleaner.
Longer term, wire an Emergency Start Button with shorter but beefer wires within the cabin, incorporating that relay unit shown by R.Johnstone. That's what I did for mine.