[esnb74]

Hi everyone. I have Kohler CH23 in a Cub Cadet 3235 that is not running right at all that I have been posting the restoration of it in a different thread. http://www.mytractorforum.com/showthread.php?t=255687

I don't have any experience with small engines but have rebuild several Chevy & Ford V8's as well as antique farm tractors engines. I got most tools or can get them on loan from O'Reilly's.

History: When I bought it a couple years ago it came from a Titan dealer on an online auction that told me it "Ran fine but had some cosmetic issues". I bought it and had it shipped to me in NE from ND. When I got the tractor it would barely run good enough to drive it on the trailer. The gas was like turpentine - so I assumed that and a good carb cleaning would fix it. I have put a bunch of time into painting last fall while the weather was still nice, thinking I would get to the engine this winter. That didn't really happen - so I am working on it now.

Here is a video of it running last week: http://s596.photobucket.com/user/du...D6-8565-0000119B937C5C5D_zpse8c53913.mp4.html

I put a spark plug tester between the plug and coil wire and I have spark on both sides. Compression test: Right: 80-70, left 60. I assume compression should be 120 or higher. I have tore apart the carb and cleaned it really good and installed a carb kit. When I had the left valve cover off everything was nice and clean. I replaced the rear main seal as it was leaking really bad when I got it. The hour meter has under 500 hours on it.

How do it figure out what is really wrong with it? Do I tear the heads off to see if the head gaskets are blown and to see the cylinders? Any advise is really appreciated as I need to decide whether to fix or part out. I don't need the tractor as I was probably going to sell it when I completed it anyway. The price was right and I'm good at painting and fixing cosmetic issues - when I was told by a Titan dealer in ND that it ran fine - I believed them. (won't make that mistake again)

 

[RED-85-Z51]

Sounds bad man...almost like its out of time, did you ensure that the timing key was in place when you put the flywheel back on? I know sometimes, you slide on the wheel, and the key pushes out the back.

 

[esnb74]

Sounds bad man...almost like its out of time, did you ensure that the timing key was in place when you put the flywheel back on? I know sometimes, you slide on the wheel, and the key pushes out the back.

I believe I did . I checked it over pretty good. It does make me wonder seeing how it ran better (but not very good) before I took it apart. :dunno:

 

[flash5153]

That is the first video that I have seen it run. If you can really call that running?? lol

If not the key,,,what about the cam??? Red? Is there a way he can check the valves/cam before he pulls the heads off??

Other than that ,, could the coil/s be bad?? Out of adjustment?? I doubt it,,but ??

I think there is hope for this engine without a total rebuild,,just need to figure it out.

 

[esnb74]

There is a lot of suction on the carb when I crank it over. Something else I noticed. I have the fuel shut off and after cranking it for just a few seconds, my hand that was on the carb had a lot of gas on it (plus i had the fuel shut off last night doing all the compression tests.

Plus, I just realized that I didn't have the throttle open when I did the compression test last night. How big of a difference does that make? Do I need to do it again with the throttle open?

 

[JDfiles]

I believe I did . I checked it over pretty good. It does make me wonder seeing how it ran better (but not very good) before I took it apart. :dunno:

That's called provocative maintenance.

 

[RED-85-Z51]

The choke should be open, the plugs should both be removed, and the throttle on the carb, should be wide open, when compression testing.

Something to check, if you can see it..is to remove the plug on one head...and stick a dowel down the plug hole, and rotate the engine by hand, until the dowel comes all the way up and stops. Now, see if you can look down and see where the magnet on the flywheel is, in relation to the coil. I dont have one on hand ot compare against, but I think at TDC, the magnet should be just past the last leg of the coil, going clockwise.

 

[esnb74]

The choke should be open, the plugs should both be removed, and the throttle on the carb, should be wide open, when compression testing.

Something to check, if you can see it..is to remove the plug on one head...and stick a dowel down the plug hole, and rotate the engine by hand, until the dowel comes all the way up and stops. Now, see if you can look down and see where the magnet on the flywheel is, in relation to the coil. I dont have one on hand ot compare against, but I think at TDC, the magnet should be just past the last leg of the coil, going clockwise.

Thanks. I will retest the compression tonight. I might be able to see in through air filter hole in the flywheel shielding to see the magnets. Would having the throttle closed and one plug in make a big difference in the compression reading?

 

[RED-85-Z51]

the throttle closed...if it was indeed closed on the carburetor...Yes, IVe seen it change 10-15%.

 

[austinado16]

Super impressive restoration job!!! Seriously.....unreal.

Regarding the running; you can probably rule out carb, by simply pulling the choke out partially, or shooting some starting fluid in brief bursts, over the top of the carb. If it runs more normal, that would mean you've got a fuel delivery problem.

Based on your video, I'd say the timing is late (retarded) and it's firing on the down stroke, rather than just before the piston hits TDC. If it's got metal key on crankshaft, it's possible that you pushed the key out, and it stuck to the flywheel magnets, so you never heard it fall to the floor. If it's an alloy shear key, it's possible you sheered it off and spun the flywheel when you tightened the bolt. I've seen that, just a month or so ago on a guy's new engine install that he did himself.

Pull both plugs and both valve covers, and rotate via that front double pulley, until you've got one hole at TDC with the wood dowel (I use a screwdriver). You can probably see the left side (seated in the tractor seat) magneto(coil) looking down through the carb, so rotate the engine so that the left piston is at TDC and the valves for that cylinder aren't moving. You'll notice that when the left side is at TDC and firing (what we're after here) the right side valves will be in "overlap".....in other words, the right side rocker arms are passing each other, one coming up, and one moving down. So with that left side at TDC, the magnet on the flywheel should be as Red says, sort of just coming passed the magneto....because the plug fires just before TDC.

I had one of these last year, so I know what a huge PIA it is to remove and install the engine, but I think that's where you're headed.

BTW, while you didn't do the compression test correctly, if you cranked the engine until you had maximum psi on the gauge, you probably got a pretty accurate reading. 70psi is enough for initial firing, and you basically got that in both holes. If you had wear or damage, your readings wouldn't be so close to the same for both sides. I just think your spark is chasing your piston.

Super nice machines and I still regret flipping the one I had......but it's hard to turn down the kind of money they bring out here.

 

[flash5153]

Super impressive restoration job!!! Seriously.....unreal.

Regarding the running; you can probably rule out carb, by simply pulling the choke out partially, or shooting some starting fluid in brief bursts, over the top of the carb. If it runs more normal, that would mean you've got a fuel delivery problem.

Based on your video, I'd say the timing is late (retarded) and it's firing on the down stroke, rather than just before the piston hits TDC. If it's got metal key on crankshaft, it's possible that you pushed the key out, and it stuck to the flywheel magnets, so you never heard it fall to the floor. If it's an alloy shear key, it's possible you sheered it off and spun the flywheel when you tightened the bolt. I've seen that, just a month or so ago on a guy's new engine install that he did himself.

Pull both plugs and both valve covers, and rotate via that front double pulley, until you've got one hole at TDC with the wood dowel (I use a screwdriver). You can probably see the left side (seated in the tractor seat) magneto(coil) looking down through the carb, so rotate the engine so that the left piston is at TDC and the valves for that cylinder aren't moving. You'll notice that when the left side is at TDC and firing (what we're after here) the right side valves will be in "overlap".....in other words, the right side rocker arms are passing each other, one coming up, and one moving down. So with that left side at TDC, the magnet on the flywheel should be as Red says, sort of just coming passed the magneto....because the plug fires just before TDC.

I had one of these last year, so I know what a huge PIA it is to remove and install the engine, but I think that's where you're headed.

BTW, while you didn't do the compression test correctly, if you cranked the engine until you had maximum psi on the gauge, you probably got a pretty accurate reading. 70psi is enough for initial firing, and you basically got that in both holes. If you had wear or damage, your readings wouldn't be so close to the same for both sides. I just think your spark is chasing your piston.

Super nice machines and I still regret flipping the one I had......but it's hard to turn down the kind of money they bring out here.

It's not so bad to remove and install the engine after some practice. lol The drive shaft is biggest problem ,,other than that,,it's not all bad.
I got to where I could do it perty quickly!!!
Good info BTW!!!

 

[esnb74]

RED & austinado16: Thanks. I will try to do this tonight as I should have some time and report back tomorrow. BTW, It's a metal key on the crankshaft. Maybe the coils are just weak and not throwing a hot enough spark? Is that possible or is it an all or nothing deal when it come to the coils? Or could the wire be shorting out on a cover or something. I did get a good shock through the insulation when I was holding the left wire last week.

 

[flash5153]

I am willing to bet,,that at least one head gasket is blown,,if not both. This is on top of your other issue.

These things are still fairly easy fixes and not all that expensive. So it's not a bad thing at this point.

Make sure you have new plugs also,,not sure if this was ever discussed. It is a definite thing!!!

It would be great if you pull the flywheel and find the key is the issue!!!
Good Luck

 

[esnb74]

I am willing to bet,,that at least one head gasket is blown,,if not both. This is on top of your other issue.

These things are still fairly easy fixes and not all that expensive. So it's not a bad thing at this point.

Make sure you have new plugs also,,not sure if this was ever discussed. It is a definite thing!!!

It would be great if you pull the flywheel and find the key is the issue!!!
Good Luck

Maybe, if I get ambitious tonight, maybe I will just pull the engine back out and pull the heads & flywheel and see what condition this thing is really in? Worse case is that I learn something more about small engines. :trink40:

Another quick question? I was just looking through some pictures. The flywheel key on the crank is a half moon on the bottom and sits down in the shaft, so how does it get pushed out when the flywheel is installed? That doesn't seem possible? Am I missing something? I remember working pretty hard to get the key level so the flywheel would slide on.

 

[flash5153]

Maybe, if I get ambitious tonight, maybe I will just pull the engine back out and pull the heads & flywheel and see what condition this thing is really in? Worse case is that I learn something more about small engines. :trink40:

If you do take the heads off,,do it carefully and try to save the gaskets. That way if they are not bad,,you can reinstall and use until you find the other issues.
Once she is running better I would then get new ones.

Most places have these gaskets in stock!!! If they are real bad.

 

[austinado16]

Don't tear anything down yet. IMO, you still need to prove what's going on.

I do a lot of V-twin work, and I've yet to see a Kohler with blown head gaskets. I'm not saying it isn't possible, but I've not seen one. I see it often on Briggs stuff though.

The Kohler V-twins are an extremely well built engine. I've seen a bunch with snapped rods, but it's always due to being run low on oil. Briggs do the same. I've also seen one, or maybe 2 now, that have flat lobes on the cam. But these pop when they run, and are easy to diagnose.....just remove the valve covers and start them up. You'll see which rocker isn't rocking.

If I had yours, I'd fire it up and mist some starting fluid over the carb. If it took off and ran fine, I'd know I had a carb issue. If it didn't change, I'd know I had a timing issue....or maybe some seriously low compression. So I'd hook up a compression tester to one side, leave the other side along, and fire it up on one cylinder long enough to get a solid reading on the gauge. If that produced something over 120, I'd repeat on the other side. If I was over 120 on the other side, I'd be heading for the flywheel.

My experience with spark is that you either have enough to fire under the load of compression, or you don't, and it won't run. I've had mags produce spark outside the engine, but not once the plugs were installed. I've had plugs, usually Denso's do the same. In fact, just had a Kawi 17hp V-twin in yesterday that wouldn't run, even on starting fluid, but would bite you if you finger tested for spark. Dropped a new set of plugs in to replace the Denso's, and it ran just fine.

One more test. With it running, touch both exhaust pipes to see if one is cold. If they both burn the living [email protected] out of you, you know both cylinders are firing and that it's not sitting there running on one hole. Twins will run on one cylinder.

Take your time, be methodical, don't go off on wild goose chases. And don't tear anything down. Be in the mindset of, "Everybody needs to prove they are working." And then set a course to accomplish that working from the most basic, to the most complex possibility. If there's something that you can't diagnose, you diagnose your way around it, making everything else prove it's functional, which leaves only that one thing that you can't diagnose.

 

[esnb74]

Good advise.

 

[RED-85-Z51]

The Command Twins had a HUGE problem with blown head gaskets, but they generally presented the same way...severe oil use and lack of power under load.

As for the woodruff timing key...it pushes out, I cant explain how or why, but they are a pain in the butt. I just did a stator repair on one and I spent more time trying to get the flywheel back on with the key in properly, then I did actually making the repair. What happens is, the key catches on the flywheel, and slides down and out, and falls away. The way kohler did it, its very easy to think that its in,when its not. I finally ended up putting a drop of red loctite on the key and tapping it in place, letting it sit 10 minutes, then putting the wheel on. Its just the swkward weight of the wheel, and how easy the key falls away. Soem are tighter than others though, and are much less complicated to do.

 

[rscurtis]

RED is right about the head gaskets, I would never try to re-use one unless it was an emergency and that was your only choice. From the short video, it's only running on one cylinder. Remove the valve covers and look around.

Basically, this engine is 1/4 of a V8 that uses Chevy lifters and Oldsmobile style rocker stanchions. It's not rocket science.

 

[esnb74]

RED is right about the head gaskets, I would never try to re-use one unless it was an emergency and that was your only choice. From the short video, it's only running on one cylinder. Remove the valve covers and look around.

Basically, this engine is 1/4 of a V8 that uses Chevy lifters and Oldsmobile style rocker stanchions. It's not rocket science.

Good to know. I didn't get out to the shop tonight. Playing with my 2 yr old until he went to bed and then decided to watch Top Shot. I will try to work on it tomorrow night and try to diagnosis the issue.