Starter switch sporadically engages starter

[skunther]

I’ve been having this issue with my 3GM30F for some time. Sometimes when I press the start button, I just hear a click, but no cranking, and I have to press the start button several times to get the starter to engage and crank the engine.
The click seems to come from somewhere near the starter switch, not from the solenoid at the starter. Do I have a second solenoid? If so, it is working, but it isn’t engaging the starter solenoid. Is there then likely an issue with corrosion on one of the wires between the solenoids?
I have a 1995 Hunter Legend 35.5.

 

[dlochner]

This is a known issue with Yanmar diesels. The root of the problem is voltage drop due to undersized wires in the harness and/or corrosion on the connections. There are several ways to deal with this, all of which involve replacing the wire between the start switch and the starter and solenoid.

 

[JoeWhite]

What happens if you place a short across the starter switch contacts?

 

[LloydB]

It is possible someone also had an earlier problem starting and added a second relay near the start button to send higher a voltage than the original voltage provided by the start button. An accurate wiring diagram including wire size along with verification that all connections are clean and tight probably will answer your question faster than replacing the diesel.

 

[Benny17441]

You could simply route new parallel wiring outside the harness. It is a known malady, but yet Yanmar has not been able to resolve it. I think with use and age in the marine environment the wires acquire increased electrical resistance which causes the drop in voltage to the solenoid.

 

[skunther]

This is a known issue with Yanmar diesels. The root of the problem is voltage drop due to undersized wires in the harness and/or corrosion on the connections. There are several ways to deal with this, all of which involve replacing the wire between the start switch and the starter and solenoid.

Are any of the ways to deal with it established as the best method?

 

[dlochner]

Are any of the ways to deal with it established as the best method?

Too many variables to say which method is best. Each boat is different which dictates to some extent how to deal with the issue.

In the stock mode, power for the solenoid comes from the power connection on the starter, this is the connection to the battery. The wire then runs to the key switch with a jumper to the start switch and then back to the solenoid. When the key switch is turned to the On position it provides power to the idiot lights and sensors and to the start button/switch.

On my boat, I took power from the positive busbar, which is just below the engine panel, to the key switch and replaced the wire from the start switch to the solenoid. For both of those connections I used 10 ga wire. Doing this reduced the wire run by half and increased the size of the wire from 14 ga to 10 ga which dramatically reduced the voltage drop in the circuit. This worked for me because my positive busbar is less than a foot below the engine panel.

Other methods use a relay to control the power to the solenoid or rely on increasing the wire size. I don't know enough about your boat to give you any specific advice. Perhaps another Hunter owner will chime in.

 

[heritage]

So far, I have not had this problem with my 2gm20f,. If It does occur, I would first check for loose wiring connections and then unplug the large connector between the engine wiring and the start panel and check for corrosion. If that all looks good, I would sister a 10 gauge wire directly from the starter button to the solenoid.

 

[Ken13559]

Beside running a parallel wire for the start button, I wired a separate starting circuit (shorter wires) within the salon. That is my emergency start panel when outside start button/circuit gives problem.

 

[Benny17441]

Beside running a parallel wire for the start button, I wired a separate starting circuit (shorter wires) within the salon. That is my emergency start panel when outside start button/circuit gives problem.

I had a boat where I abandoned the start button at the panel and mounted one inside the companionway. It was no problem to walk a couple of steps to crank the engine. I use to say that I did it for theft prevention by having a dead switch in the open cockpit and the real switch under lock and key. I reality I never got around to rewire the outside one. They are also convenient when working on the engine.

 

[sailcapt340]

Check out the posting on 9/10/23. “Push Button Starter Testing”.
It has more of the answers you are looking for. Same boat and engine as yours.
Judging from it views (800+) there are a lot of people having this issue as well.

 

[skunther]

Update, upon checking with my wife pushing the start button, I can confirm that the starter solenoid is clicking each time and seems functional. I have one bad ear and thought I heard the click coming from the starter switch, but I was mistaken. There does not appear to be a second solenoid.
The question now is if the starter solenoid is working, but it usually takes multiple tries before the starter will crank, what is likely the pronlem?

 

[dlochner]

Still the same problem. The solenoid does 2 things, it makes the connection to provide power to the motor and it engages a pinion gear. If the pinion gear does not engage properly power is not provided to the starter motor.

Here are a couple of pages from the shop manual for 3JH2E on the starter. Yanmar uses the same system on most (all?) of it marine engines.

 

[JoeWhite]

Measure voltage on 12v input cable to the starter cable while starter button is pressed. It should read battery voltage 12v. If not then the contacts of the solenoid are bad. You can abandon the built in relay and install an external 80Amp contracts relay. You can measure the voltage across the power cables when starter button is pressed. It should be zero, if not, then bad relay contacts.

 

[dlochner]

Measure voltage on 12v input cable to the starter cable while starter button is pressed. It should read battery voltage 12v. If not then the contacts of the solenoid are bad. You can abandon the built in relay and install an external 80Amp contracts relay. You can measure the voltage across the power cables when starter button is pressed. It should be zero, if not, then bad relay contacts.

The Yanmar solenoid is not a simple contact switch, it also drives a lever to engage the pinion gear. Take a look at the documentation I posted.

 

[mermike]

I can assure those who are still wondering about this problem that the solution is to replace the wire.

 

[JoeWhite]

The Yanmar solenoid is not a simple contact switch, it also drives a lever to engage the pinion gear. Take a look at the documentation I posted.

Thanks for that info. I did not know that
The idea is to eliminate electrical problem before removing it for mechanical problems.
Let us know what you find. I am curious.

 

[skunther]

So the issue is still voltage drop, which I should address by boosting the wiring gauge via one of the methods mentioned above?

 

[mermike]

Voltage drop pretty much covers it but the causes are multiple connections and too small a wire gauge.

 

[skunther]

If I am getting a solenoid click every time I push the start button, this clearly indicates the wiring from the start button to the solenoid is not an issue, correct? Does it not indicate the issue is somewhere at the starter itself?

It is very intermittent. It usually cranks the first time I push the start button, but occasionally I need to press it 2 or 3 times to get it to engage, so testing by jumping at the start button does not seem would provide any definitive information in my case.