yanmar stinks

[Muttondressedaslamb]

I have a 1987 vintage Pearson 27 which was repowered in 2000 with a Yanmar 2gm20f. While motoring into the harbor after a day of sailing, I noticed a strong "electrical" smell emanating from the cabin. It did not smell like diesel or engine exhaust. With the engine still running, I looked under the hood and didn't see any smoke. I throttled back from 3000 to 2500 RPM and the smell faded. Yanmar customer support thinks it is coming from the alternator and suggested that I run the engine with the alternator disconnected to see if the smell re appears. Any other suggestions? What else might it be. I hate to spend $600.00 for a new alternator if I don't have to.

 

[mz4wheeler]

I have a 1987 vintage Pearson 27 which was repowered in 2000 with a Yanmar 2gm20f. While motoring into the harbor after a day of sailing, I noticed a strong "electrical" smell emanating from the cabin. It did not smell like diesel or engine exhaust. With the engine still running, I looked under the hood and didn't see any smoke. I throttled back from 3000 to 2500 RPM and the smell faded. Yanmar customer support thinks it is coming from the alternator and suggested that I run the engine with the alternator disconnected to see if the smell re appears. Any other suggestions? What else might it be. I hate to spend $600.00 for a new alternator if I don't have to.

It is most likely a fried diode pack. Check the output voltage from the alternator. If your batteries are charging fine then you may have to look elsewhere for charred wires.

You can pull off the alternator and have it rebuilt by a reputable alternator/starter rebuild shop. I had mine done for $80 and it works fine.

 

[Ralph Johnstone]

With the engine still running, I looked under the hood and didn't see any smoke. I throttled back from 3000 to 2500 RPM and the smell faded. /quote]

Any chance you've disconnected the alternator from a load for even a second recently ? That could fry the diodes as explained by mz4wheeler.

On the other hand, it may be entirely unrelated to the engine itself. Remember that the 2GM sucks in air at a theoretical rate of 34 cu. ft. per minute @ 3,000 RPM, so any smells generated in the engine compartment are likely going to be pulled into the engine while under power

Before laying down any hard earned cash, I'd want to verify the exact location of the burning insulation.

 

[Muttondressedaslamb]

With the engine still running, I looked under the hood and didn't see any smoke. I throttled back from 3000 to 2500 RPM and the smell faded. /quote]

Any chance you've disconnected the alternator from a load for even a second recently ? That could fry the diodes as explained by mz4wheeler.

On the other hand, it may be entirely unrelated to the engine itself. Remember that the 2GM sucks in air at a theoretical rate of 34 cu. ft. per minute @ 3,000 RPM, so any smells generated in the engine compartment are likely going to be pulled into the engine while under power

Before laying down any hard earned cash, I'd want to verify the exact location of the burning insulation.

Lucky for me, I think the problem required only a little time and no money. It appears to be a loose alternator belt which was slipping at high rpms I tightened it and no more smell

 

[kito]

So Yanmars don't stink after all.........

 

[woodster]

when you get a new belt get Gates from NAPA store and you will be getting a new belt

 

[Ralph Johnstone]

when you get a new belt get Gates from NAPA store and you will be getting a new belt

And a much higher quality belt.