As I have mentioned previously, a couple weeks ago I purchased a non-running Diesel Pro KDE6500E Generator. It is a diesel powered 6500 watt generator with electric start, and as it was not running at the time of my purchase I bought it for the bargain price of $120. I found the generator via Craig’s List and went to look at it about 45 minutes from my house.
The gentleman from whom I purchased it said that he had loaned it out to a friend in running condition and had received it back not only in non-running condition but in several pieces. He said that the guy that he had loaned it to had put off road diesel in it and now it had no compression. Hmm, I thought, the off road diesel doesn’t have anything to do with it not running, but it certainly didn’t have any compression. It was missing a battery, the pull start was in pieces, the covers were all off the frame, it had parts that even the former owner didn’t know where they went, and as stated it had NO compression. Many small diesel engines (this one included) are equipped with a compression release valve to make them easier to crank and start. This valve blocks the exhaust valve partially open to prevent the engine from making compression. I had a hunch that it could be something simple that was wrong with this engine and it turned over smoothly and seemed “tight” so I took a bit of a gamble. I though if nothing else, I could probably sell the generator head or use it myself with a new engine. The gen head was worth what I was paying for the unit so I didn’t feel it was too much of a gamble. Besides He took my $120 offer when he was asking $150 for the unit. I was feeling pretty good about my chances. So home again we came with my new project in the back of the truck.
As a sidebar for those not very familiar with the design and function of a 4 stroke internal combustion engine the animation below courtesy of Wikipedia may provide a bit of insight into the function of this type of design. This animation is depicting a gas engine (as is evidenced by the presence of the spark plug in the middle of the head) but you get the idea. The piston travels up and down in a total of four strokes per cycle, thus the term a 4 stroke engine. The strokes are known as 1-Intake, 2-Compression, 3-Power (or Combusion), and 4-Exhaust. The blue indicates incoming air and fuel, the brown indicates exhaust. The difference in this animation is that this one shows small cams (overhead cam design) operating the valves directly whereas my diesel generator uses a traditional push rod design. More detail on these dufferences is for another time.
Image via Wikipedia
THIS animation and its accompanying description may provide a quick primer into the subject a little more insight into the design and function for those concerned with earning extra credit or just interested in learning more.
Once we were home again, the tinkering began almost immediately. The first thing I did was to pull the valve cover (this engine is an overhead valve design). When turning the engine over my hand, I could clearly see that the intake valve was moving up and down as it should be but the exhaust valve was hardly moving at all. The push rod coming up to the rocker for the exhaust valve was barely moving. Strange, I though. So The next step was to pull the cylinder head. Since this generator is of the “IMPORTED” type (Made in China) and information was at a premium, I measured the torque required to remove the nuts from the head studs. This is an imperfect method of measurement, but it was better than having no idea what soever what the torque specs should be. After recording the figures, I removed the four nuts, the cylinder head, and the intake and exhaust valve push rods. Much to my delight, everything inside the engine looked really good. Little or no wear on the cylinder wall, the piston was in good condition, and most importantly, the cylinder head and valves were in good condition. I put the push rods on top of the lifters and turned the engine over by hand. I was able to get both push rods to move correctly this way so I felt confident that the camshaft and lifters were working properly.
Now ideally, after a good cleaning, a new head gasket would have been installed, but since parts are difficult to obtain for these MiC gensets, and since this unit uses a copper head gasket, I though I would re-assemble it and see if I could get it to make some compression. I thoroughly cleaned all the mating surfaces, then re-installed the head. It was difficult to get the valve push rods to line up correctly with the rockers and the lifter while holding the head with the other hand, but after repeated attempts I was able to get everything to line up. I then re-torqued the head stud nuts. Now with everything re-assembled and turning the engine over by hand I had LOTS of compression. So much compression in fact that it was difficult to turn the engine over by hand on the compression stroke. Now we’re talking! Valve cover affixed, oil level checked, fuel tank cleaned out and refilled, fuel shutoff on, attached a car battery to the leads, turned the key and “CLICK” was all I could get. To make short of an hour or more of continued tinkering, let’s just say that the starter wasn’t working even after multiple attempts to get it to crank. The starter motor appears to have cranked its last. The pull start was inoperable as well since the shadetree mechanic that took it all apart lost the “dogs” that actually make the mechanism turn the engine over. Well Shoot! Now what? I tried turning the engine over by several different methods and was unable to get it to turn over fast enough to start. Did I mention that it had a lot of compression? Finally, in desperation I tried the old tried and true method of rope wrapping the flywheel thimble and giving it a good sharp tug. It turned over nicely by this method, but still wouldn’t start. Now typically I don’t like using ether in diesel engines (or at all really) but I do keep a can of it in the shop. A snort of ether down the intake and a quick tug on the rope, and would you believe it, it popped and fired! Now we were making some real progress.
It would run on ether (and WD-40 which is another diesel engine trick), but would die immediately once the spray was stopped. No fuel to the injector was the diagnosis. I removed the bolts securing the fuel pump and pulled the pump out of the block. I couldn’t believe my luck. Apparently someone had removed the pump in an attempt to “fix” the non running engine and had put the pump back in with the fuel shutoff in the wrong position. The fork inside the engine that was intended to operate the shutoff lever on the pump was in the wrong position to line up with the actual shutoff fork on the engine case. A quick flip of the lever and I was able to reinstall the pump. I turned the engine over by hand with the fuel line to the injector unhooked, and wouldn’t you know it I was pumping fuel now. So I hooked the lines back up, cracked the line loose at the injector and turned the engine over by hand once again until I had bled all the air out of the lines. Once that line was re-tightened, when I turned the engine over by hand I could actually hear the injector click when it “popped off” its spray of fuel into the cylinder. Another quick shot of ether into the intake, a few pulls of the rope, and lo-an-behold! It’s Alive!
So today on my way home from work I stopped at our local power equipment dealer. This place is a locally owned, family affair in which the whole family is employed, so I try to support their establishment with my business whenever possible. I had talked to them a few days ago and they had indicated that they may indeed be able to source the necessary parts (namely the starter) for my little project. So I stopped in and showed them my parts. For kicks I had thrown the recoil starter assembly in the box with the starter just in case they could indeed get me those parts as well. As it turns out the Diesel Pro generator that I have is the exact same model that they sell under the name Eastern Tools and Equipment (ETQ). The helpful young man in charge of their parts department asked me an unexpected question when he said “Would you prefer new parts or would you consider a used starter?”. What’s that? A deal!? You bet! So a quick trip to look at a unit that they were stripping for parts and it yielded me a new (used) starter and the whole recoil starter assembly for the pull-it-yourself price of less than $100 out the door. I could hardly believe it.
So this evening after dinner, a few minutes of tinkering, a few nuts and bolts from my own personal stock and I was left with a nicely running generator that will start with the key or the recoil starter.
I took the time to put together a cord to connect the 240 Volt output of the generator to the welder outlet in my shop and the generator powers the entire shop with no problems. I connected a number of devices to the generator including lights and my 120V air compressor that frequently will trip a 20A breaker and the engine hardly bogs when the load is applied. Needless to say I am thrilled to have a running (diesel) generator has cost me less than $250 and a few hours of tinkering, which doesn’t really count anyway since this habit of tinkering is a hobby of mine.
Until next time: