Heater plug removal

[Serenity]

I was talking to a current owner of the Yanmar engine. He removed his heater plugs, taped off the ends and plugged the hole. The engine runs fine without them. Has anyone else done the same? One member said they were a bear to get out on the flushdeck. On my engine box, it looks like the right socket will screw them out.

[kerrye]

Are you referring to glow plugs? Engines will often start in warm weather without glow plugs but won't start in cold weather without them.

[Serenity]

The YANMAR 315 does not have glow plugs. They are more like a heater coil to heat the air going to the engine as an emission control.

[Carl]

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This is what you have to do in a flush deck to remove and replace. I did mine last winter as PM as recommended. Once I replaced them, I sealed the pieces with epoxy and then used some 4200 to glue them back in place. Next time will only need a knife to remove them.

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[Serenity]

Carl, you "glued" them in place? Why?

[Carl]

Not the heaters, the pieces of fiberglass that were cut out with a hole saw.

[Grey Eagle]

They are Induction Air Heaters, at least that what I think they are called. The problem is that the coils can with age break off sucking the pieces into the cylinders causing who knows what damage?

I have been told that there are plugs that you can get to insert in the hole that the coil was removed from.

Has anyone done this?

[Serenity]

A guy in my club has the 370 Yanmar and he plugged them up. No difference in performance except his alternator isn't under load when first starting the engine.

[Paddy]

I was also warned about the "catastrophic failure" when they rust out and are sucked in through the intake. My local Yanmar dealer told me to cap them if I don't use the boat in the winter, but I do go until 12/15, so I simply replaced both.

I can say with certainty that the idle at start is rough in mid-November by me, so I assume the heater plugs are doing something to help as apposed to not heating the intake air at all.

[Serenity]

I pulled Serenity early because the other half and I are taking a cruise to Bermuda, if there is anything left. I spoke to the service manger about the heater plugs and removing then. Not a problem, Yanmar sells plugs just for that reason. It was interesting, yesterday morning when I was driving the boat over to the yard, my voltmeter didn't register 14 volts until I was running 15 minutes. Normally it takes less than 5 minutes. It was about 50 degrees The heater plugs put a tremendous amount of drain on the alternator.