3YM20 Starter Problem

[awol]

My 3YM20 has started faultlessly for abour 400 hours - just turn the key and instant go. That is until last week when the 1st turn of the key to starter position silenced the alarms but then nothing. Subsequent attempts started as normal but it takes more and more attempts now to kick the starter into life. When the key is in the starter position there is a 20amp draw on the battery, voltage drops to 12.5v but no vroom. I am tempted towards the relay that I believe is between the key and the starter solenoid - any other places to look, probe, fiddle or hit with a hammer?

 

[Boater Sam]

Solenoid poor connection or failing. Believe it or not, a poor connection or low battery can cause more current draw than normal.

 

[VicS]

My 3YM20 has started faultlessly for abour 400 hours - just turn the key and instant go. That is until last week when the 1st turn of the key to starter position silenced the alarms but then nothing. Subsequent attempts started as normal but it takes more and more attempts now to kick the starter into life. When the key is in the starter position there is a 20amp draw on the battery, voltage drops to 12.5v but no vroom. I am tempted towards the relay that I believe is between the key and the starter solenoid - any other places to look, probe, fiddle or hit with a hammer?

The 20 amp draw is the solenoid. It suggests that the intermediate relay is probably OK.

Maybe the solenoid contacts are bad or it is sticking.

 

[awol]

The current draw was up to 35amp today with still no starting whirr. Turned out it was the earth connection to the engine, tight but not clean. Why after so many faultless hours it decided to give up beats me. Anyway, now clean and protected.

 

[KAM]

My 3YM30 developed an intermittent starting fault after 1500 hours. It was very intermittent maybe averaging 1 in 50 or 100 starts but usually started eventually. I thought I'd fixed it several times over a couple of years when I found various small faults. Root cause turned out to be the relay which is attached to the back of the engine near the gear box and subject to fairly severe vibration. Its worth identifying the relay as in extremis a short across the terminals will get the engine stsrted.

 

[wonkywinch]

I tried bump starting mine, but couldn't find any hills so thought this might work ..

 

[Bilgediver]

The current draw was up to 35amp today with still no starting whirr. Turned out it was the earth connection to the engine, tight but not clean. Why after so many faultless hours it decided to give up beats me. Anyway, now clean and protected.

That was one of the problems with Faithful a few years ago.. We jump started by taking a lead from battery negative to the alternator bracket..

The connections at the earthing bolt include aluminium, brass, stainless steel and copper ! As yours looked perfect till taken apart but a good clean up sorted it.