Yanmar 2gm20 won't crank

[Moncoeur]

Hi CF members
I have a Yanmar 2GM20 that works well mechanically, however, it will not turn over (crank) using the electric start. On the most recent occasion, it had started as per usual, by turning the key and pressing the ignition button, then the engine ran well for about 3 hours. After turning it off we sailed for a number of hours. I then tried to restart the engine using the same method but it would not start. The ignition light did not come on and the ignition button did nothing when pressed. Fortunately I was able to start the engine relatively easily by hand cranking it and flicking the decompression switches. To try and work out what the problem was, I borrowed a brand new battery and replaced the usual starting battery, but still the engine would not crank it (nor did the ignition light come on when the new battery was connected). I have not done any more fault finding to this point. Any ideas as to what might be happening?
Thanks in advance.

[Amnesia II]

I’d check every connection from batteries to starter motor including ignition and earths. Start with the simple things.

[martinworswick]

when i had the same problem with the same motor it turned out to be the battery isolation switch,looked fine,no corrosion,changed it problem gone away!

[charliehows]

yeah any loose connection in the starter circuit will cause the starter to go to sleep. The usual sympton is a click from the solenoid followed by - f-all. I'm impressed that you can hand crankstart the engine juggling the decomp. levers, my 2qm-20 has far too much compression inertia to do that...

[alctel]

The fact you don't even get a light makes me suspect you blew the fuse that's on the back of the engine for the solenoid, if it's like my 2qm20

Nice job handcranking it though, that's awesome!

[lockie]

I am also impressed by your hand-crank start. Would you please share with us how you managed it?

[Moncoeur]

Hi, thanks all for good suggestions. I will check the fuse, starter circuit and battery isolation switch. As for hand-crank start the trick is to be able to pull both decompression levers at the same time without using your hands. To do this, I simply thread a length (about 1 metre will do) of 5 mm cord through both holes in the tops of the decompression levers. Tie a thumb knot (or larger figure of 8 knot) in the cord on the far side of each lever so that when the cord is pulled towards you, both levers activate at the same time (two levers = two knots). The other end of the cord is tied around my upper thigh. There is no slack in the cord. From a standing position (back and knees well bent and using both hands) hand crank the engine for about 8 revolutions and on the 9th revolution simply straighten the leg (slightly) that has the cord tied around it. This will pull the cord and easily trip both levers at the same time. The engine should start. I hope that makes sense.

[wagsea6b]

You are my new hero.

[lockie]

Originally Posted by wagsea6b

You are my new hero.

Me too, if I can get it to work as you describe

[charliehows]

Thats not bad - anyone who tries it on a 2qm, let us know if it works (I'll give it a try myself asap and report back)(a variation could be; tie the pull cord to one decomp lever only, might improve the chance of a start by reducing decomp drag to one cylinder only...)