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Sunstar Kohler 20 hp Command - any hope?


WITom

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[IMG]http://img259.echo.cx/img259/3852/kohler1medium1fl.jpg[/IMG] I'd say crankshaft seal, correct? I'm not an expert on small engines. I tore it down and was quite suprised at the condition of the engine after seeing this. Cylinder bores are not scored, pistons and rings are fine. Heads are warped though - will be buying new heads and valves for it. Is there any hope for this stator? Can they be tested? I did notice that the volt meter stayed right at 12 volts for the hour or so that I did run this tractor unlike my other Sunstar that runs between 13 & 14 volts when operating. What else might be wrong? Hour meter shows 793 hrs. [IMG]http://img259.echo.cx/img259/3533/kohlerstatormedium7my.jpg[/IMG]
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There is a running AC check on the stator with out the regulator. First look fried. Second look, oil build up. Go with second look. You can download OH book at Kohler web site.
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Kohers i have tore apart look like that, and people wonder why they throw rods? Because they cant cool! There is a resistance check also, cant remember much about it, but its in the book. It looks like it will be ok,
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Hi, What is the history on the unit you are talking about?? Why do you feel you need to buy new heads and valves. I am not implying that you are wrong, but give us some details and maybe we can help you put the head money in the savings account. Is this question related to another post I didn't see. Will be glad to try to help, just need more info. We save warped heads regularly. Stators are a much less common failure than regulators. Most of the stator failures we see are because the wires got pushed up and the flywheel rubbed the wires in two. Al Eden
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Al - I bought this tractor off of ebay, so I don't know anything about the history. I checked the heads according to the Kohler service manual by setting them on a piece of glass and checking for trueness using a .003 feeler gauge, which they say is the max. allowable. The feeler gauge slipped in on both heads right where the spark plugs are. I guess I didn't check to see how much they are out of whack, but book says to replace if over .003. Again, I'm just a novice at this engine stuff, so if you have any advice, please pass it along. I took a small engine shop course in high school where we each rebuilt a 5 hp Briggs, but that was 17 years ago. Guess you could say I know just enough to be dangerous! :) Thanks! WI Tom
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Tom, We came into this world naked and had to learn everything we know afterward. Not knowing is a normal part of life, not wanting to learn, I consider a waste. As long you are interested in learning there are many people that are willing to help and get personal satisfaction out of helping people. You just don't know some things in this area. I am sure you could teach a lot of us in other areas. Nuff for the soap box. Now for the heads. We check them as you did only with a straight edge. We resurface a lot of heads. If the heads are off an engine in warranty, we replace them. We feel the customer deserves a new straight head and they don't have a flat rate number for reworking them. If the customer pays, we usually try to save them. We use a flat plate. If you have a table saw, or belt sander with a cast iron surface ground table it will work. Also a piece of thick glass or a piece of 1/4" aluminum plate with the back side that has been surfaced. Anything truly flat and solid. Lay a sheet of 80 grit procuction sandpaper on the plate grit up. Put the head on the paper and holding the edge of the paper so it doesn't slide push the head down and away from you. You could probably use one of the spray glues to hold the paper from sliding too. We use a large belt sander with a ground table. I grab the belt at the close roller and with my fingers push up on the bottom of the belt around the roller to tighten is a little and keep it from moving and then push the head on the belt with the other hand. Pick it up and turn it 1/4 turn and repeat, pick up and turn it 1/4 turn and repeat. Continue this process until the head surface is shiny all over. First only the high spots around the bolt holes will shine. When you get to the point that the sandpaper is starting to cut the low spots, you are getting close and a little more and the low spots may still show a little grayer than the rest but you see the sandpaper is cutting it check it. By turning the head 1/4 turn with each stroke you will keep it flat and if there is any uneveness in the sandpaper or the plate, this evens it out. Also you end up with a cross hatch that bites into the gasket. We have observed that most Briggs Vangard heads are warped, but after the original "set" they seem to stay flat after resurfacing. Seems like they get "prestressed". Very few Briggs and Kohler flat head engine heads don't need resurfacing, the only thing that lets you use these warped heads is that they are thin and bend easily when tightened. I would say we resurface 90% of the heads we take off. If this is confusing or not clear, just say so and I will try to clarify it. If you have any other questions post them, and we will try to help you. Al Eden
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Thanks Al, it makes perfect sense. I don't know why I didn't think of it myself as I have used a process similar to this where I work. I used to build explosion proof electric motors and, after assembly, would check each motor for a gap between the frame and endbell. If out of specs, I would often correct a bad frame by using sandpaper on a granite slab. What I would do is "paint" the edge of the frame with a black Sharpie marker and then use a circular motion on the sandpaper. As the high spots got sanded off, the ink would disappear and show right where the low spots were. I'd just keep sanding until all the ink was gone and then I knew I had a nice, true frame. Anyhow, I will certainly give that a try - don't know how much new heads cost, but I'm sure they're not cheap! Thanks again! Seems each forum that I frequent has one or two guys who really know their stuff and are more than willing to help out. "You Da Man" on this site!! :)
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