Anyone Familiar with Kohler 12 hp K series

[rarefish383]

My 12 hp kohler won't start. Conked out last year, and just started messing with getting it started. First no spark. Hit the points with a points file, they were a little fuzzy, still no spark. Before I ran up to get new tune up stuff I threw the compression tester on it. Only about 60 lbs, put a shot of oil in cylinder and it jumped to about 80 psi. I don't know what compression these old flat head motors should be at to run. It was running fine when it conked out. Acted like it just ran out of gas. A friend gave us a 14 hp Briggs bottom shaft, but I'd rather get the 12 hp side shaft running before I have to fab up the mounts to go with the bottom shaft, Joe.

 

[tooold]

What's the compression of the 14 hp Briggs bottom shaft engine?

 

[TK]

They were notoriously somewhat low and would still run. I've seen a couple come through that were right around that range and ran fine, tuneable through the carb. Usually when the compression gets too low they won't take a consistant tuning.

Could be due time for some carbwork, fuel lines, filter, tank inspection, etc. Them old Walbros did a fine job, just need a little lovin. Can you get a spec number off the motor somewhere?

 

[atlarge54]

The Kohler has an automatic compression release----I don't know the procedure to get a real compression reading. The K series Kohlers are really tough motors. I'd see what new points and condenser do.

Not cheap to rebuild with machine shop bill and all easy to spend $300 to $400, but when you're done you're going to be decades away from doing it again. I've never been a fan of B & S engines.

 

[Patrick62]

ignition...

Make sure your primary is good, continuity test. Check the secondary as well, it will be couple thousand ohms. be sure the condenser is good. Get the points nice clean and well adjusted. THey have to open at the exact TDC, unless Kohler figured in a little advance.
60 pounds might be low, but it will fire and run with it. You can get a six pack of compression from the beer store. It will run real nice then

If the engine has "compression release" built in it, the way to run a accurate compression test is to spin it backwards.

 

[gink595]

The Kohler has an automatic compression release----I don't know the procedure to get a real compression reading. The K series Kohlers are really tough motors. I'd see what new points and condenser do.

Not cheap to rebuild with machine shop bill and all easy to spend $300 to $400, but when you're done you're going to be decades away from doing it again. I've never been a fan of B & S engines.

Yeah that is right, you wouldn't get a accurate reading because auto compression release. The best way would to be a leak down test with a leak down tester.

Proform 66839 Dual-Gauge Leakdown Tester Dual-Gauge Leakdown Tester

 

[tooold]

This site has info on k series engines.

Kohler K series swapping questions - MyTractorForum.com - The Friendliest Tractor Forum and Best Place for Tractor Information

It talks about having to rotate the engine backwards to check compression.

Then, this site is mostly about the k series in pulling garden tractors. lots of info.

http://gardentractorpullingtips.com/index.htm

 

[sawinredneck]

Even 60psi is plenty! I've seen them running on 35psi!
Get your ignition system figured out, clean the carb, check the fuel lines, make sure it's getting gas, check the plug, I've had a lot of problems of late with Champion spark plugs, they look good and spark in air, but wont spark under compression. I'm done with Champion anymore!
It's hard to kill those old engines, it's something simple, don't make it complicated.

 

[rarefish383]

Thanks all, kinda what I was hoping to hear, tough old engines. I know my Wisconsin 4 cylinder only has 65 PSI factory spec, and it's a flat head like the kohler. Can't really spin it backward cause it's elctric start and no pull rope. I'll go ahead and tune it up, and I know it has some carb issues, but it was running well, when it last ran. Thanks again, Joe.

 

[atlarge54]

You don't set the timing on these engines, all you can do is adjust the gap. Timing is fixed at the cam.

The last tractor (non Kohler) that gave me problems, meaning it just died and wouldn't restart---points were dirty. I actually had to remove a get pretty agressive with emery cloth to get running. Several attempts at sanding in place failed.

It isn't rare to have fuel pump issues if it's set a long time.

 

[albert]

You set the timming by small changes to point gap. The is a round hole in the side of the main fan shroud. Timming on most is set to the sp mark. I think it's 16 btdc.

 

[atlarge54]

My Kohler book makes no mention of setting timing only setting point gap at .020". I seriously doubt playing with the gap would offer enough timing change to be significant. Set the gap right, the timing is what it is and is determined by the lobe on the cam which is geared to the crank.

 

[woodchop]

Make sure that the small push rod that activates the points is free. Remove the points and polish if necessary.

 

[zogger]

Limited experience with the K engines here, just one... but so far..sorta tempermental on getting the ignition and carb adjusted correctly. There's an exact magical place, then they run well, miss anything by an eeny and good luck with that. And once you go to start pricing replacement parts and so on, egadszooks! Gets right into the "you got to be kidding me"! range. I mean silly ridiculous expensive. Close to a grand for a single cylinder replacement engine?

There are some aftermarket ignition module dealies you can get that supposedly will make them run much better and eliminate point hassles and so on. I bought one but haven't tried it yet, that's one of my upcoming early spring projects. If it doesn't work to get mine running again (rebuilt carb, new fuel pump, new under the dash some electronic gizmo, new points, new allegedly correct coil, clean head and top of piston, adjust valves, etc etc, all the usual stuff..still no start), I am scrapping that thing and going to either electric drive or an import cheap diesel. Thrown enough time and money at this thing as it is, sorta soured for me. I mean I got it used and ran it a lot, can't complain, but once she started not wanting to start, just beyond me. And I ain't paying what they want plus all the labor (mine and the machine shop) to rebuild one, just silly when you can get a durable single cylinder diesel engine for about the same or even less money.

 

[Bob95065]

I seriously doubt playing with the gap would offer enough timing change to be significant.

Not true. I had the points set wrong on my K181 8HP engine that I rebuilt for my Lickety Log Splitter. I was careless when I set the points and had the timing advanced. When I tried to start it the engine backfired pulling the recoil starter handle clean out of my hand. The engine continued spinning backwards wrapping the starter rope ever tighter until it snapped launching the starter handle past my right ear and ricocheting off the wall across the garage. This happened in a spilt second - I didn't even see the handle coming. I shudder to think what would have happened to me if it hit me in the face. It pulled muscles in the fingers of my right hand. I did get it started and it missed really bad when warm at high engine speed. I decreased the point gap (retarded the timing) and the problem went away. That engine starts on one pull now.

I grew up on an International Cub Cadet with a Kohler 10 HP engine. I should have known better. The points gap must be set correctly. I agree with the other posts in this thread.

 

[atlarge54]

I'm still a doubter on the sensetivity of point gap to timing----yes it does have some impact. Now keep in mind a lobe on the cam operates the points, the crank makes two revolutions for every one revolution of the cam so any error is cut in half relative to position of the piston. Just how significant is .005" to .010" in point gap relative to piston location? Not very much. This is also taking place while the piston is near TDC and piston movement relative to crank movement is near its minimum.

Put me in the school where if your points are even close your timing is correct.

 

[albert]

I'm still a doubter on the sensetivity of point gap to timing----yes it does have some impact. Now keep in mind a lobe on the cam operates the points, the crank makes two revolutions for every one revolution of the cam so any error is cut in half relative to position of the piston. Just how significant is .005" to .010" in point gap relative to piston location? Not very much. This is also taking place while the piston is near TDC and piston movement relative to crank movement is near its minimum.

Put me in the school where if your points are even close your timing is correct.

It's easy, put yourself to school and hook up a timing light and see how much the timing moves due to changes in point gap. You will also hear and feel how the engine reacts.

 

[tooold]

I agree with albert. I grew up working on motorcycles in the seventies and I found I would be rewarded for being a perfectionist when it came to doing tune ups. You can be "close" and the engine would run, or very small tweeks could could make them run sweet.

 

[Bob95065]

It's easy, put yourself to school and hook up a timing light and see how much the timing moves due to changes in point gap. You will also hear and feel how the engine reacts.

Another one of my time-consuming hobbies is old motorcycles. I have a 1964 BSA that I am restoring. I worked with one of the biggest British motorcycle shops on the west coast that is very reputable. The owner stared with British motorcycles when he was 18. He is now in his 70s. I trust what he tells me.

When I got the bike I spent hours in his shop asking questions and gathering information. One of the questions I had was how to tune the ignition. The way the points are set up is diabolical. There is a plate behind the cam that holds both sets of points for the two cylinders. The plate is adjustable around the cam but the individual points are not adjustable to the other set. In other words you have to set them perfectly the first time. I asked the owner how critical the points setting was - it couldn't be that precise considering how difficult setting two sets of points on a fixed plate was. He got really excited and went into a long treatise on how important the points gap setting was. It turns out BSA used very thing crowns on their pistons. If the points were not set right you could advance the timing too much. The other problem with detonation is the way octane is rated was changed when lead was removed from fuel so the number on the pump looked the same as when lead was added to gas. I read extensively on what happened to gasoline when lead was removed. 93 octane today is not what it was in 1964. Advanced timing combined with lower octane fuels would cause premature detonation and knocking which could blow out the piston crowns under the right conditions. He had pistons there to prove it. They sold a timing kit which consisted of a degree wheel and a pointer that was indexed to TDC of one of the cylinders. You use a continuity tester to determine when the points open. The pointer and degree wheel reveal where in the stroke the points were set.

All this said the way you set the points determines the timing which does have an effect on your engine's performance. The case for the Kohler isn't as sensitive as my BSA because an L-head engine doesn't develop the compression as a overhead valve motorcycle and it isn't seeing the loads as a bike. If you get the points gap set incorrectly enough the engine will not run right or run at all. I had an experience I posted about yesterday where I had a backfire that nearly resulted in a nasty injury and caused my right hand to hurt pretty bad for a while.

Think about the gap setting. 0.020" isn't a big gap. That gap is pretty sensitive. If you are off 0.002" that is a 10% error from the factory spec. Being off a small amount isn't a big deal with an engine that isn't sensitive like an L-head single cylinder Kohler but if you work on something hat is sensitive to timing you have to be dead on right.

 

[saxman]

Down through the years my family has had several Wheel Horse tractors that all had the old K series Kohler engines of various horsepower. I still have one with a 16HP K series, I had trouble several years ago with it being hard to start and after it warmed up it would quit. I pulled the flywheel to check the key to make sure it was not partially sheared, I put in a new set of points and set them on a nats azz and finally changed the condenser and it was the cause of all my problems. I don't think there has been a more durable air cooled engine ever made than the old K series Kohler, They are build to last.
Steve