Yanmar Starting Problems

[dlochner]

The motor is a Yanmar 3JH2E. The problem is intermittent. The instrument panel is the Yanmar bare bones panel with a Tach and idiot lights that don't seem to light up.

The engine either starts immediately within a couple of seconds or it doesn't. Turn the key on, press the start button and she fires right up, or the solenoid clicks and nothing happens. Press the start button rapidly several times and sometimes it fires right up, sometimes not.

All the wiring has been inspected, cleaned up, and reinstalled. Still sometimes it fires right up, sometimes clicks away.

Replaced the start battery and replaced the starter, same issue.

Sometimes switching to the house bank (4 GCs) it works, sometimes not.

What I haven't done yet is to delve into the mysteries of the wiring harness. The schematic does not show any fuses and the terminal connections seem clean and tight.

There is no starter interlock to prevent starting in gear. The problem has existed from shortly after we left the dock for the first time.

Any suggestions on where to look next? (Yachtworld is not an option, we just bought this boat 4 years ago.)

Thanks.

 

[reworb]

I would bet its your wiring harness. Its a common problem The following is from a post I made on another thread:

Sounds like the same problem I had with my 2GM20. The problem was/is the wiring harness, Yanmar cheaped out on the wires from the stater motor they were undersized and non tinned. I replaced the red and white wires (not sure if that's the correct colors for your's) with number 10 tinned wires from the starer motor to the button and key. Never had a problem since, starts first time every time. The non-tinned wires corrode over time and since they are small to begin with resistance builds up not delivering enough juice to the starter. I was told that the multiple attempts to start temporarily lowers the resistance from the heat or something. I read about installing a second relay but that seemed to add a layer of complication and no less work than simply running two new quality wires

 

[py26129]

I think the above post hit it on the head. I had the same problem with my 3GMF. Typically it'sa related to the whitye wire running form the started button ot the low voltage side of the starter solenoid. I installed the second solenoid (<$20 at Radio Shack), as mentioned above, and it now starts 1 time, every time. What a pleasure.

The install was pretty straight forward and i can dig up some details, if you would like.

Cheers
Matt

 

[Benny17441]

Old wiring (5+ years) to the solenoid seems to gain resistance which results in a drop in voltage which fails to activate the solenoid. The best solution I have encountered is to by-pass the harness wiring by running new external wires to the solenoid. Some use an auxiliary solenoid and others just relocate the push button near the engine compartment.

 

[HOB No1]

Have a 3YM30 that had similar starting problems, sometimes it would start, sometimes not. When not starting, could hear "clicking" at the starter. Problem was related to the wiring harness being 10 years old. A new/additional relay was installed to bypass the wiring harness, and works every time. Worth considering that approach as it does not require running wires back to the switch.

 

[Warren Milberg]

I posted on this item some time ago:
"The issue may be the aging wiring harness and its inability to produce -- and deliver -- the needed voltage to the starter solenoid. This comes from impedence in the wires and all the connectors. It's worth checking and cleaning all of them. In my case, I added a fused 12vdc relay to the solenoid -- bingo. No problem since.

To read this item, go to Boat Info>Knowledge Base>Engines>Yanmar>Starting Problems on this site. There are 3 items posted there about this topic and its solution."

 

[dlochner]

Thank you to everyone who replied.

The consensus is the wiring to the solenoid. We'll be changing that!

The wiring diagrams I have do not show a second solenoid, however, they indicate that one may be needed on longer runs. It is less than 10' from the switch to the solenoid, so it may not be necessary to add the additional solenoid.

In the meantime, before I get it wired, I'm wondering about using a remote starting switch, one of those clip on jobs. I think I have one in the basement.

 

[Bill Roosa]

warren's solution is treating the symptoms. The problem is too many connections in the starter control circuit resulting in low voltage being supplied to the solenoid. Unless you plan on swapping engines on a regular schedule it is ok to neuter the engine electrical harness of ALL the quick connects. Or just run a new dedicated starter control wire from start button output to starter solenoid control terminal. I did the former and have had NO problems for over 5 years. It also fixed several weird instrument/idiot light problems to boot. FWIW

 

[NYSail]

I went the additional solinoid route..... never had a problem after that. Good luck

 

[Benny17441]

In the meantime, before I get it wired, I'm wondering about using a remote starting switch, one of those clip on jobs. I think I have one in the basement.

Not with alligator clips that may come loose. It is not a bad idea to install an second push button switch near the engine compartment so that if you push the panel switch and nothing happens you take a few steps to the companion way and push the auxiliary one. Because of the short distance and new wires installation this one will likely work everytime.

 

[py26129]

What NYSail said. +1

 

[pfaffk]

I had the same intermittent starting on my 2GM20F. I simply ran new wire and have had to further problems

 

[Apex]

On a YSM-8R: Ground APPEARED solid, but when I disconnected, cleaned and reconnected the problem was resolved.

 

[Warren Milberg]

warren's solution is treating the symptoms. The problem is too many connections in the starter control circuit resulting in low voltage being supplied to the solenoid. Unless you plan on swapping engines on a regular schedule it is ok to neuter the engine electrical harness of ALL the quick connects. Or just run a new dedicated starter control wire from start button output to starter solenoid control terminal. I did the former and have had NO problems for over 5 years. It also fixed several weird instrument/idiot light problems to boot. FWIW

Bill is spot on: my "solution" does treat the symptom. I meant to do just what he suggests, that is, get rid of all the quick disconnects which suck off amps going to the starter. Yet the "relay fix" did do away with the symptom, which was intermittent starting. Then I got lazy and 12 years later I am still meaning to install a more permanent fix -- one of these days.

 

[SG]

When you say it won't start, DLochner...

You mean it does i) nothing; or, ii) it cranks over and won't start? IF it just won't crank (like silence) then:

The solution I found involved few dollars and fixed the problem which we had 12 years ago with our Yanmar 4JH2.

I wouldn't screw the wiring to the solenoid unless you something really abnormal. Measure the voltage coming through the harness when the key is turned to Start. The issue may not be FROM the harness, but the whole path to and from the battery (or batteries).

The simple fix is to interpose a simple relay kit near the solenoid. Wire the harness to the relay and put a "shorter" , and more robust marine grade wire directly to the battery through the relay. The relay will trip at anything above, say 10.5 volts. The existing solenoid doesn't like to actuate at voltage that should NORMALLY trip it.

I believe that is the first thing to do. You'll save a lot of money (your starter probably wasn't an issue, your messing with the harness, etc. etc.

I've had friends who replaced a lot of expensive equipment, been uncertain that they can start the engine when they need it, etc.

If you want to discuss this directly, send me a private message.

 

[kloudie1]

Yup. I ran a new power wire to the switch panel, bypassing the push connectors, and I ran a solid wire from the pushbutton back to the solenoid... bypassed the harness connections both coming and going.. works fine..

 

[SG]

That effectively is what the relay does that is described above.

 

[dlochner]

When you say it won't start, DLochner...

You mean it does i) nothing; or, ii) it cranks over and won't start? IF it just won't crank (like silence) then:

The solenoid clicks, but the starter motor won't consistently start. When it does start, it starts immediately, within 2 seconds or so, but, sometimes the starter won't spin. This just doesn't make sense. On the wiring schematic it looks like an ordinary solenoid, however, it isn't. It shouldn't take very much energy to close a solenoid to connect two wires. And why would the relays, increasing wire gauge, or eliminating connectors make a difference if not much energy was needed?

The answer, as it turns out, is buried in the Service Manual (yeah I know, RTFM, I did, but I was reading the wrong section). See the attached page from the manual.

The electromagnetic switch apparently does 2 things simultaneously, it connects the primary DC wire to the motor and it operates a lever that pushes the pinion gear out to engage with the ring gear. If the pinion gear engages with the ring gear, the starter motor starts and the engine starts. If the pinion gear does not engage the ring gear, a spring forces the solenoid open and the starter won't spin. The proposed solutions all serve to increase the voltage at the solenoid/electromagnetic switch which gives it enough power to engage the pinion gear with the ring gear allowing the contacts to contact and the starter to spin.

The easiest, cheapest solution is to replace the wire from the switch to the solenoid with good clean connectors. If that does not work, then adding a relay may be necessary. Yanmar does note that if the 6 Meter extension harness is used, then a separate relay is needed. It's beginning to make sense.

I'll replace the wire next week and report back.

Thanks for all the suggestions and the motivation to dig deeper into TFM.

 

[reworb]

The easiest, cheapest solution is to replace the wire from the switch to the solenoid with good clean connectors. .

Don't use any connectors, if you can do that. Bypass the existing wire in the harness with a direct run of proper marine grade wire.

 

[NYSail]

Yup.