Starting a Yanmar 1GM

[blackbeard]

There have been innumerable threads on this, mainly connected with an occasional reluctance for the engine to turn over at the first button press. The usual remedy (assuming that cleaning up the 30 A fuse terminals and other contacts hasn't provided a complete solution) is to fit a relay, so that pressing the start button causes relay contacts to close such that the solenoid now gets a direct (fused, of course, and via main switch) input from the engine start battery, thus avoiding the volts drop in Yanmar's convoluted wiring loom. Before I actually get around to doing this, I would like to ask a couple of questions:

I am aware of an instance where the relay seized closed (due to corrosion), causing the starter motor to rotate even when the start button wasn't being pressed. The end result of this was a need for a new starter motor (could have been much worse). Apart from this instance (reported in CSSA POG club newsletter), has anyone else had a problem of any sort with a relay in the start circuit?

It occurs to me that some of the resistance in the cable loom could be avoided by a short fat wire (fused, of course) from battery (via main switch of course) directly to the "ignition" (you know what I mean) switch. This still leaves the resistance in said switch and in the starter button switch, but it should be less than with the original set-up and there's no need for a relay. Has anyone tried this, and if so, with what result?

 

[Cloven]

I had this problem for years with a 2GM for years. Finally sorted last season.

Used the direct thick wire method but no success other than it bypassed the stupidly placed Yanmar in line fuse and now I have a fuse I can get at if needs be.

Solution was finally to fit a relay (suggested by Marine Power, Burseldon) AND a new start button (suggested by EP Barrus). Had no problems starting since and no issues with the relay. Engineer reckoned that the contacts inside the original (1997) start button were damaged due to arcing and so only intermittently pased the full current needed to start the engine. Fitting the relay has meant that the current through the push button is very small and so arcing should not occur.

PM me with an email address if you want a circuit diagram and I'll send it on to you.

 

[Georgio]

Hi Cloven,
I'm not the OP but I would like to see the diagram if you are happy to share. PM on it's way.
thanks.