Yanmar 1GM10 Starting problem - electrical

[Severnman]

Forumites your advice requested (after having done a little trawl on the forum). Boat was relaunched the other day after a brief spell ashore. The engine refused to start with no power or alarms at the switch panel. Both batteries onboard are less than 3 months old and showed good voltages (in excess of 12.8V). Checked the usual suspects including battery connections, negative block connection, looms, 30Amp fuse etc etc and on closer inspection noted live connection to starter motor not tight. Also it appeared that the stud thread had worn away where battery cable joined stud. I packed with washers, retightened and engine started fine. However this seems to be a temporary fix as the fault has returned ie no power to switch panel (no relay ckick etc nada!). After a couple of times doing the same task with success (ie retightening, cleaning etc)it is now producing no positive results. Am I looking at a starter motor overhaul/ replacement or have I overlooked something basic first? Your thoughts, as ever, welcomed.

 

[sailorbaz]

I would have had the same problem with my 1GM10. During a recent refit I took the connection off to clean it up and as I was rubbing the terminal on the end of the cable, it came off in my hand! There had been only one strand of copper still connected. I checked all the other battery to engine cables and the earth was almost as bad where it was bolted to the gearbox housing. The cables were the originals from 1985 and have now been replaced with automotive ones with heat sealed ends.
Sailorbaz