Starter wiring.

[Ed Schenck]

Can anyone enlighten me on the actual wiring for a new "pre-engaged" starter on my new Yanmar 3YM30. The wiring diagram in the manual is as I would expect, battery to the 'B' post and start wire to the 'E' post. But the new starters do not have those posts. Instead it appears that all the wires((battery switch(hot 12v), panel wire, and factory bundle(incl. start wire and alternator?)) go to the same post. Following is some dialog from the UK Yanmar help site:"it's a standard style pre-engaged starter motor with three solenoid connections. The main + is just the power supply to the starter. There is a separate thin white wire which is the switching wire to energise the solenoid (via the key switch & start relay) and a third terminal which takes the power from the solenoid to the motor itself. The operation is described here: http://www.powerbase-auto.co.uk/starter_motors.htm "Well there may be a "thin white wire" somewhere but it is encased in the factory bundle. On my old 2QM20 it was the old way. All 12 volts supplies and sources were taken off a common solenoid post. Then there was a separate white wire from the pushbutton/key switch to a separate solenoid post to energize. Any ideas are welcome.

 

[Fred Ficarra]

Ed, I wired such a system into my 69 Camaro

many years ago. But I had to use a separate solenoid. It was a hot rodder trick to get around header heat problems.To just hook all connections to the single post seen in your picture is unheard of,,,well OK, impossible. At least without magic. Sounds like you have the wrong manual and/or a missing auxiliary relay.

 

[Fred Ficarra]

OK, look inside that cable bundle cover.

Is the large battery cable seen in your photo inside that cover? If so, follow it. There must be a relay at the other end. That's where the key switch wire has to be connected.If that's a 'ship's cable',,,never mind. But there has to be a way to apply power to that solenoid. With no other connection to it, power can only come from that red LARGE cable. And because of that, it HAS to be switched via an auxiliary relay. If not, the starter would run anytime the battery selector switch was on. That's obviously wrong.

 

[Fred Ficarra]

And here's your engine manual part number;

M9961-03E100. Maybe you have the wrong one. Don't bother checking for it online. I tried that. Yanmar!

 

[Bill Roosa]

Not sure how many terminals you have but I've seen

solenoids with two and with three terminals. The two terminal type has one +12 volt large terminal and one small control terminal. They are not necessarily on the same end of the solenoid. The terminal that takes the power to the starter is actualy "internal" and you just can't see it. You can use the +12 volt for anything you want as it is commonly used as a power supply post too. So the circut for the control wire is from the +12 volt terminal to the ign switch to the starter switch and then back to the control terminal on the solenoid. I've also seen the control terminal be a "ground" type where the control circut is from the control terminal on the solenoid to the ign switch to the start switch to ground. You can tell the difference by noting the voltage on the control terminal once the +12 power termnal is attached. If it has 0 volts on it it is a stardard type and if it has +12 volts on it, it is the 'ground' type.

 

[Ed Schenck]

Battery to starter.

Hi Fred, thanks for the help. That large(#4) red cable is from my battery switch. Then I have two #10 wires going to the electrical panel(because of the ham radio draw). Everything else was under the rubber cap as part of the engine bundle. Part from the alternator and sensors, the rest from the new engine panel. That panel has idiot lites, a tach, a stop button, and the key switch with start position.I have had power to that post, everything works off the electrical panel. But I have not tried the starter. The boat is still on the cradle until Wednesday.Once I forgot to turn off the battery switch and went to tighten that nut with a long extension. I inadvertently touched ground and the starter spun. But if grounding is how you energize the solenoid then everyhing else on the boat would temporarily shut off. The reason I think my wiring may be correct is because of the factory bundle. Both the start wire and the alternator wire are in that bundle and go to the same post. The battery switch wire and the sources to the electrical panel have to go to/come from that same post.Yet in the little manual you see the two sides of the start relay. One side goes to the starter post marked 'B'. That is the same post as the battery switch cable and all other 12 volt taps in the diagram. Then it shows the other side of the start relay going to post 'S' (not 'E' as I previously wrote).I have a new spare starter that I bought for the 2QM20. It is 12698-77010. It looks more like what I am used to. It has a tab which is probably post 'S'. The bottom post on the solenoid is a heavy wire to the starter. The top post would be like my old 2QM20 starter, the place where all continuous 12 volts lives. Maybe the new starter is wired the same way and I just cannot see well enough under/back there? Time for some mirrors and directed light I guess.Posted this and then saw Bill's response so am editing. It could be as Bill suggests. The "tab" on the new starter could be the 'S' post and the 12 volts to the starter could be 'internal'. I like that thinking, thanks Bill.

 

[Fred Ficarra]

I'm sure you'll keep us posted. sorry

That was bad,,,,Unless Yanmar has re-invented DC electricity, the power has to come from somewhere and go back. It can't do it from the same post. That's a dead short. And when you put that wrench on the big post and hit ground, causing the starter to spin,,, you didn't hit ground. That would have caused a shower of sparks from that same dead short. What you hit was the post that energizes the solenoid. It has to be there. Wanna borrow my mirror? Is there a boat without one?

 

[Fred Ficarra]

Ed, This is all new stuff, right?

It was all assembled and you just plugged your panel harness to the engine and your battery cable to the large post, right?If so, what are you worried about? Crank it with the key. If it starts, great. Shut it down and check your pre-launch list. But it probably needs bleeding, especially if you haven't tried to start it. In any case, IN THE BOAT YARD is the place to sort out a new engine. You don't want to launch and then figure out what might not be right. And with a new install, something is not right.At your raw water intake, rig up a garden hose adapter and a ball valve shutoff. (a garden hose style, cheapy is all you need. Then you have all that you need to run your engine on the hard. When you have it running smoothly, hook up the through-hull to the engine and relax. You know it'll start when you splash. Don't forget to keep us posted. And I'd get those Ham radio wires onto a breaker panel switch, not the starter post.

 

[Ed Schenck]

C'mon Fred, give me. . . .

a little credit here. Both sets of wires from the starter 12 volt supply feed the panel. Everything on the boat is fused or on a breaker.And I have run my engine many times on the hard. Yes, it is factory wire except for my 12 volts to the same post. And I will do as you suggest, just try it. But it is ninety miles to the boat and it is nice to have a plan. Sorry to vent, just tired I suppose.