Kohler magneto ignition problems

[geneP]

I have a, '83 model Troy Bilt Horse III with a Kohler K161T manual start engine. It was not firing at all and I couldn't get a reading from the secondary side of the coil so I replaced the coil. It runs now, but the faster it runs the more intermittent the spark gets. There is no smoke or bad noises from it. With teh throttle set low it will start first or second pull on the rope. Advance the throttle and no start. It idles pretty well, but at full throttle it sounds like a hit and miss engine. I've checked and rechecked the points and timing. Using a timing light, it fires just a little above the center line of the timing window. The timing light verifies intermittent spark when it is running rough. I haven't changed the condenser until I've run all the options out. Before I put a ton of money in this engine and it still not be right, I want to repower it.

I've read tons of threads on this engine and ignition seems to be the prevalent topic. I have a tired K181 electric start and I'm considering using the battery ignition from it on this K161 and see if it corrects the problem. Any ideas about how to correct the intermittent spark would be appreciated.

 

[Leejohn]

Points might be floating, check points spring, spark plug boot and coil wire.

 

[geneP]

Thanks for the suggestions. I agree that it sounds like something is failing at higher rpm. The points spring seems strong. When I loosen the screw holding the coil/condenser wire I have to push strongly on the spring to be able to slip the wire terminal out. The magneto coil is new, so all wires to plug and points are new.

 

[geneP]

Well, my face is red. When I changed the coil and reinstalled it and the bracket that holds it I didn't tighten the bolts. I was hearing a little rattle and it sounded like it was under the flywheel. Removed the flywheel and found the problem. Runs fine now.