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Kohler CV26 EFI missing running rich

Discussion in 'Mechanic and Repair' started by crater, Aug 26, 2012.

  1. Keith

    Keith LawnSite Gold Member
    Posts: 3,977

    My CH26 was finally diagnosed after fighting with it for three months, at two different dealers, and I ending up buying another mower because it was down so much. A third specialist was brought in and found a small cut in a wiring harness causing it, initially to ground out intermittently and run rough. But eventually got so bad that the mower would barely run.

    Everything was thrown at it. Temp sensors, O2 sensors. Ended up just being a cut in the harness.
  2. crater

    crater LawnSite Member
    Posts: 36

    Restrorob: Yea that was a thought also, I used super glue and I could not budge them after it set. I have no idea what heat does to super glue, so yes it is a concern. I thought of JB weld but I thought it would be too thick so I went with super glue that was labled for use on metal.

    I can see value in the flow chart, but I can run down it (with yes's) until the end where it asks if the problem was resolved. Obviously the answer is no, so it circles back. And it really doesn't say "well maybe you may want to look at something else". Basically replace this or that until fixed, but what happens if nothing in that line of diganostics fixes it? Alot of $$ wasted.
    As far as leak down test goes: The manual say that "some models" come with this auto compression release mechinisim. Does mine? how about yours? Kohler did not publish which models had it, in my service manual anyway. I think Kohler dropped the ball on that. Anyway I don't have a leak down tester but I do have a compression tester and both sides test 185psi. So at least even psi is good on most engines BUT Kohler doesn't spec out what they actually should be, just that a leak down test should be performed, cause ours might have a ACR.

    Keith: Yea my thought also, wiring harness issue. I have had bad connections make it not start when cold before so I think that is the next direction.

    I think my next step is to tear it back down, check the magnets for correct position, check the air gap of the speed sensor, rip the seat off so that I can get at the wiring harness better, and start a wire by wire check. I read in a service bulletin that they had a problem with a stainless steel connector somewhere that was used as a ground. I think the bulletin said it wasn't used on the CV but was on the CH so I shouldn't have it right. Anyway just some things to look for i guess.

    A fuel pressure test is in order also, the pump seems to make a funny sound now and again, so maybe that will be first check. Also does anyone think it could be injector related?
  3. piston slapper

    piston slapper LawnSite Platinum Member
    Posts: 4,240

    Crater...check the ac output on the stator...that will tell you if you are making enough voltage..
    185 is about right on compression...your gauge may be a little off ..180 psi is new.
    Check your connections...unplug and plug everything back in..looking for corrosion or melted connectors..
    Its usually something simple..once you find it...
    Hang in there...
    Posted via Mobile Device
  4. crater

    crater LawnSite Member
    Posts: 36

    thanks for the help everyone. I'll start the traceing tonight let you guy know what unfolds.
  5. crater

    crater LawnSite Member
    Posts: 36

    well I finally got to it on Sat.

    1)Checked the air gap of the speed sensor/flywheel (right on)

    2)Pulled he flywheel-removed magnets reordered then N-S-N-S-N-S. For anyone else's info the magnets are each N----S-----N and the other three are S----N----S. Just picture the N and S as the ends of each individual magnet.

    3)Took the wire loom off the entire engine harness and found a nicked wire up by the ECU. Don't know how it happened or if it was actually grounding out but I repaired it with shrink tubing.

    4) Repair a leaking fuel line where it meets the fuel rail.(that of must just started, never noticed it before)

    5) Put everything back together and it runs like a top. Checked the voltage coming out of the stator. 6.5v-7v on both sides, so that tell me it's charging.

    All in all about 7hrs of labor and I couldn't be happier.

    Thanks to all for the info.

    Bty what type of glue do you use to re-stick these magnets? I looked at some epoxy but it said "not for use over 200d". So I just super glued them again, obviously I still have a concerns.
    Last edited: Sep 23, 2012
  6. Restrorob

    Restrorob LawnSite Fanatic
    Posts: 11,023

    I don't...... Too much risk in wiping a engine out, Good for you finding whatever the issue was.....
  7. Patriot Services

    Patriot Services LawnSite Fanatic
    Posts: 12,870

    So what is the preferred , majority accepted way of reattatching magnets.
    Posted via Mobile Device
  8. piston slapper

    piston slapper LawnSite Platinum Member
    Posts: 4,240

    I use JB Quik Weld...haven't had a repeat magnet failure in over 10 years...

    You have to put small pieces of cardboard between the magnets while they dry to prevent them from attracting themselves to each other..
    Posted via Mobile Device
  9. Keith

    Keith LawnSite Gold Member
    Posts: 3,977

    Hope you got it all sorted out. This kind of stuff can drive you nuts when you have jobs to do.
  10. crater

    crater LawnSite Member
    Posts: 36

    I tried JB Quick weld (LOVE THE STUFF) but the magnets started to slide all over especially down towards the top of the flywheel. I suppose I could have propped them up somehow. IDEA: I could have used some masking tape to hold them in place, along with some cardboard spacers as you suggest.
    I think that is in order when then season is over which is probably 1 more week here in IA. I know that a little finger nail polish remover detached them licky split when I used super glue. BUT they wouldn't budge until I put it on them.
    Restrorob: I totally agree about not taking un-necessary chances, however (in my opinion) this is not like re-using rod bearings or seals just because they appear good. And I'm not putting a warranty on anything like a professional shop would or more likely the customer would want or expect. Yea I get the $185 now or $3000 later but I tend to think if a factory worker, on a friday or on a hung-over monday can glue these suckers on then I certainly can also.:laugh: Thank for your input though, reading through this form you have certainly earned my respect and I also have to give props to Piston Slapper. You two guys seems to have a hugh knowledge base that I can see has helped a ton of people on this form alone. So THANK YOU:clapping:

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