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View Full Version : Generator Motor Tuneup


Richard and Rhonda
01-02-2011, 09:37 PM
My gennie, a 20KW Kohler, powered by a 4TN84TE Yanmar engine, was running very rough and smoking at times. It has always run a little rough and rumbly but since it ran that way since I bought the coach, I thought it was the nature of the beast.

During my adventure of working on the Series 60, I ran the gennie a lot to power the furnace and air compressor for the impact wrenches. It ran rougher and rougher over the last couple of months.

I decided to pull the injectors and set the valves. The tips of the injectors were completely covered in carbon and the injector tube in the head was occluded by carbon deposits. I cleaned the injector tips with a bronze brush, and disassembled the injector nozzles. I squirted a solvent through the tips to make sure none of the holes were boogered up. Then reassembled the injectors with ATF as the lubricant.

It took less than an hour to put the injectors back in and set the valves.

OH MY!!!!! I have a new generator.

It runs much smoother and quieter. No rumbling or stumbling like it used to do. The stumbling would wake me up at night when we were boondocking. It makes sense, the big generators really don't do much more than idle unless we are parked in the sun with all AC's blasting. The idling tends to build up carbon in the diesels.

prairieschooner
01-05-2011, 03:59 PM
I would find that carbon build up on boats when the engine wasn't being loaded or coming up to temperature properly. You do need to be sure that you do not scratch the tip of the injector when cleaning it otherwise the build up may happen more quickly.
The two things that are normally checked when proving an injector are the pressure that it takes to pop open the injector and the spray pattern when it pops open.

just a little advice for future refence.

chockwald
01-05-2011, 04:48 PM
Steve, you are a diesel Savant......

prairieschooner
01-06-2011, 05:08 PM
I wouldn't go that far, just familiar.
1st diesel that I worked on was over 40 years ago, there was a small gasoline engine to turn it over until it got oil pressure and then flip the compression lever. I think that it was a D8, I ran and worked on that monster all summer that year.