Yamaha Generator (Smoking)

[dmecimore]

Hi all.

We have a 2200W Yamaha Generator for our 2019 RT23 that we bought from the dealer along with the boat (purchased July 2020).

When we put any stress on the generator at all (even just turning on some outlets) the generator pours blue smoke. This continues as long as we pull any power from the generator at all - stops if we turn off shore power on the boat.

I know that this is something to do with burning oil, but we just had the generator service with a new carb installed.

Question is - how much smoke should we expect to see from this generator? I'm thinking not much at all, but am I just wrong about this?

Thanks.

 

[Alpina]

I don’t have a Yamaha generator but two of the smaller Honda’s and a Briggs and Stratton. Don’t use them for my boat but I’ve loaded them up and never any smoke. I’d bring it back to the serving dealer and ask them to try it under load. That’s not normal in general unless someone with that particular unit says it is.


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[KKRCRACE]

My 15 year old 2000 Honda that I use for my boat and race car does not smoke even with I big load.
KKRCRACE

 

[ixlr8]

There should be no smoke, something is wrong, get it taken care of while it is still under warranty. Almost sounds like you got a used/abused generator.

 

[FlyMeAway]

Blue smoke is burning oil.

Could be residual oil on the carb valves, but that should burn off fast when they tested the generator after servicing/replacing the carb...

Did the dealer do the Yamaha service (I hope it was them or someone authorized)? Since the entire thing is still under warranty, I'd try taking it to a Yamaha-authorized service center that isn't the one that just fucked things up...

 

[trailertrawlerkismet]

Whatever you find please report back to us so we can learn from your experience.

Jim

 

[Capt’nKarl]

Is it possible someone added some oil by mistake into the gasoline thinking it was a two cycle engine?

 

[Bobby P.]

Smoke from a four stroke engine can only be a few things.

Upon start you can get a little smoke, because when a typical 4 stroke engine shuts down it is cut off from electric (diesels can be shut down by stopping fuel flow). When you cut off the electric, the crank shaft spins, pistons go up and down a few times and can leave some unburned fuel in the head. When you start, you are igniting more fuel than you need and puff, some smoke. That should go away quickly, though. Also, this is more of a symptom in older engines, not fuel injected, which are now all electronically activated. Nonetheless, still possible.

If you are running too rich, you can get a little smoke while running. This could be resolved by checkin timing, ignition, etc. But, your problem is that your are getting lots of smoke under load, which is not a sign of running too rich, but still outside chance.

The fact that you get a good deal of smoke, and it is blue, suggests oil is burning, along with the gas. So, Capt'nKarl has a good theory here. Somebody may have thought two stroke, and added oil to the gas?

Another theory is that the oil sump is too full. There is a low amount of pressure that is appropriate for 4 stroke engines in the oil sump; if you overfill your oil sump, you can push some oil through the piston rings while running and bam, you are burning oil in the cylinder (causing smoke, more under-load).

The two above theories are probably best case scenarios here, and easily addressed. Baring those, and one we don't want is, is cracked piston, broken ring on a piston, and/or a scored cylinder.

If it is a cracked piston or broken piston ring, you'd be getting smoke consistently, and more under load.

If it is a scored cylinder, you might not get smoke until you put it under load.

Easiest test for cracked piston, broken ring or scored cylinder is to do a compression test. If you have multiple cylinders, you would test each one.

So check you oil level first. Next, make sure you have good, clean fuel. Next, check your compression. Follow these diagnostics, I'd like to hear where you are.

Oh, one other thing... Newer engines have lots of computer-driven things. It would also be fair enough to have those looked at and tested, but not something you can generally do at the dock or in your backyard, unless you have the right tools.