Engine Ground wire!

[PatTormey]

With the Yanmar (YGM20 1986 oDay 322) getting 'crankier' with each start AND I'd already beefed up the starter solenoid wire and replaced the button I decided I needed to replace the starter. Not as easy as you'd think cuz there is no access to the port side of the motor without roto-zipping an access port in the head.
The roto-zipping went easily enough and when I removed the panel I was surprised to see that the main grounding cable to the battery banks was completely rotted away, seems marine grade wiring was an option the original owner overlooked.
The starter was only grounded thru the much smaller ground wire (source unknown) as was the rest of the boat!
It turns out that for about $80 at We$tmarine you can get real marine grade 12" #2 wire and amazingly it can be pulled (from the battery box end) by securing the dead end to the new cable. The only real turn seems to be at the battery box. (striping back the rotted end didn't reveal any fresh copper)
While there anyway I decided to do something about the starter.
The local Yanmar dealer offered to sell me a new starter for $475 which would last 30 years longer that the rest of the boat so I opted for a local rebuild shop who gave me 1 day turn around, new bushings and a upgraded solenoid and a new paint job for $140.
Anyway, Blue Skies now starts like new and except for an ugly mess when the roto-zip and I had a argument all is well.

 

[justsomeguy]

...an ugly mess when the roto-zip and I had a argument...

I hope no blood was shed.
Otherwise, a good outcome.

 

[Ron20324]

Was the paint job red, or is that your blood???

 

[Brian D]

So Pat, was the gray cable on the left your ground? Is that how your found it? What are the green and smaller wire? Is that the ground that you said was the only thing helping you start the engine?

 

[Stu Jackson]

Nice report and nice job, thanks.

For other readers: That's one reason why many boating communities are suggesting that hard starting issues should usually first be traced to the ground wire, especially the connection at the engine, if not the wire itself.

 

[PatTormey]

Hi Stu, As a log time back yard mechanic and one time navy electrician I like to tell people that at least 1/2 of all 12 volt electrical problems are the ground! ;-)

 

[PatTormey]

Yep the 'fat " wire is a #2 directly to the battery terminal ground post. I didn't chase the green wire #10? but I likely goes to the electrical panel.

 

[PatTormey]

No, the paint job on the starter was Yanmar grey, I try to remove all blood before taking pictures. The only roto-zip issue was bad planning, followed by a loss of patience, and some unsightly carpentry. Fortunately duck tape comes in oDay grey and I hang my washboards in the head, hiding my shame from public view.

 

[PatTormey]

The grey ground wire was completely disconnected as I found it. I pulled it out for the photo.

 

[AndreNJ11]

Problem - Start button on Yanmar 2GM20F intermittently does not work, and engine slow to start when button does work.

I have a similar story. I have owned my boat 10 years now. When I bought it , very occasionally when I pressed the start button it would not do anything. Press again and it would work. As the years went by it became more prominent. I replaced the starter button on the panel from Yanmar. No change. I read on the forums all the discussions, including many references to the wire from the panel to the solenoid needing to be beefed up (bypassing the wiring harness).
Last year it had gotten to the point sometimes I would have to press the button four or five times before it would engage, - becoming disconcerting. I was thinking solenoid needed replacing.

I priced a new solenoid from Yanmar , approx $125 dollars. Not to bad. (A new starter was like $450 or something! Yikes!) I decided I would 'rehearse' taking out the solenoid to see if I could do it myself. I did so, and it was not too bad, but putting it back on it was hard to properly couple again the lever trigger thing that engages the starter wheel movement, I could not get it back on right. Now I really had a mess. It did not work at all now.

Time to take the entire starter off. (I still was not too afraid as I had learned how to replace a starter in boat owner diesel maintenance school in Annapolis. ) I was able to take the starter off from the front of the engine, as I was taught by using a long extension and a wobble fitting. (only two bolts as I recall). I did not need to cut a hole in the head wall.

Out of the engine, I was now able to get the solenoid back on the starter properly (still a bit fiddly but now I could see what I was doing). I tested the starter/solenoid combo before reinstalling and all was functioning again. I put it back on the engine and the starter worked. So the net of my experiment was I could do the job, either a solenoid only or the whole thing. I was about to order the solenoid, but since the engine started it was not urgent.

The thing is: The starter button has never acted intermittently again in several months! The engine started just fine, every time in the fall, when previously it would become slow to start and cranky. No intermittent start button, great starts.
I can only surmise that the electrical connection from the main cable (on one of the two bolts as shown in the prior photo) had become cruddy in 30 years. Just me taking the start off and putting it back on - the continuity of the connection was restored. And I am guessing the RPM at start is 10% higher than before, thus creating more compression for starting which helped in the fall sluggish starting.

All because of the starter bolt and main wire connection through that bolt to the engine. Even though it looked fine and the bolt seemed tight. Just 30 years of crud on the connection.

Happy days.

 

[Ron20324]

...there is no access to the port side of the motor without roto-zipping an access port in the head....

Maybe a bit after the fact, but can you move the engine block ground to some place you can see it easier?

 

[Ward H]

Maybe a negative bus bar in a visible spot.

 

[Apex]

had the same issue. ground wire appeared solid, but was not.