Alternator was smoking and glowing inside

[mrangry]

I have a Yanmar 4jh2e fitted with a hitachi 80 amp alternator on a sailing yacht and was out the other day for the first time since last November. Last year I had an issue with the starter not always engaging on first turn of the key but would eventually engage after a few turns.

We were approaching the marina and started the engine before dropping sails and it started with no issue, however I noticed a smell of electrical burning. Upon investigation I could see smoke issuing internally from the alternator with an orange glow also inside the casing. Oddly the started solenoid was also extremely hot to touch (more than usual).

We immediately shut down the engine and pulled out the genoa allowing us to sail away from the entrance. I then removed the heavy cable from the alternator going to the batteries and re started the engine with no issue allowing us to motor into the marina.

There doesnt appear to be any overheated wiring and on the face of it seems to just be failed alternator, I am just wondering if a short in the starter solenoid could have caused the alternator failure given the very hot starter solenoid and dont want to replace the alternator for it to happen again.

My thoughts are to just replace both the alternator and starter, does this seem prudent?

 

[Alex_Blackwood]

I have a Yanmar 4jh2e fitted with a hitachi 80 amp alternator on a sailing yacht and was out the other day for the first time since last November. Last year I had an issue with the starter not always engaging on first turn of the key but would eventually engage after a few turns.

We were approaching the marina and started the engine before dropping sails and it started with no issue, however I noticed a smell of electrical burning. Upon investigation I could see smoke issuing internally from the alternator with an orange glow also inside the casing. Oddly the started solenoid was also extremely hot to touch (more than usual).

We immediately shut down the engine and pulled out the genoa allowing us to sail away from the entrance. I then removed the heavy cable from the alternator going to the batteries and re started the engine with no issue allowing us to motor into the marina.

There doesnt appear to be any overheated wiring and on the face of it seems to just be failed alternator, I am just wondering if a short in the starter solenoid could have caused the alternator failure given the very hot starter solenoid and dont want to replace the alternator for it to happen again.

My thoughts are to just replace both the alternator and starter, does this seem prudent?

Looks like the alt. will be cooked, much more than likely. Yes a fault with the starter / solenoid would appear to be the likely cause. Probably need a new Alt. but any auto electrical repair shop should be able to sort out the starter Are your batteries (Engine start) OK after a possible short in the system?

 

[Boater Sam]

Check that the starter solenoid is NOT staying energised after the engine starts. Ensure that there is no voltage on the small solenoid tag.
Your alternator is probably beyond repair.