Volt drop on Yanmar ign output.....

[boatbod]

Originally Posted by Dockhead

On my installation, there is a relay for exciting the secondary (school bus) alternator plus unlocking windlass and bowthruster and turning on engine room blowers. I had a good deal of trouble with this as well, solved only by replacing some of the wiring, remaking connectors, replacing the relay.

Yanmar wiring pretty much sucks in my opinion.

It's not the wiring that's the problem so much as the location of the connectors in the harness. Normally they are right below the exhaust elbow and catch every small leak that drops on them.

[senormechanico]

Our previous boat had a Yanmar 3HM35F.
The very problem being discussed here turned out to be the wiring harness connector at the aft end of the engine like boatbod discussed.
The pins are split, and eventually lose their contact area due to compression (probably from engine vibration).

I cleaned all the pins with an old toothbrush and solvent, spread them a bit and reconnected the plug. Never had another problem with it before selling the boat years later.
Simple cleaning is a lot easier than ignoring the cause and wiring up a relay to mask the problem.

[Matt Johnson]

Originally Posted by senormechanico

Our previous boat had a Yanmar 3HM35F.
The very problem being discussed here turned out to be the wiring harness connector at the aft end of the engine like boatbod discussed.
The pins are split, and eventually lose their contact area due to compression (probably from engine vibration).

I cleaned all the pins with an old toothbrush and solvent, spread them a bit and reconnected the plug. Never had another problem with it before selling the boat years later.
Simple cleaning is a lot easier than ignoring the cause and wiring up a relay to mask the problem.

DeoxIT contact cleaner does an excellent job. I've fixed many an electrical issue with a good cleaning!

Matt