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Nuzzy

Frustrating Kohler... Help!

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Nuzzy
Brief synopsis: -Bought AC 912 with Kohler K301s -Hard starting (was thinking bad gas at time) -Finally started and drove 15 minutes before throwing rod -Tore into engine, all seemed decent so bought new rod/piston/rings and reassembled with engine assembly lube and torque specs from manual Finally put the motor back in and got everything ready to try and start it tonight. Took a bit of cranking and starter fluid but finally got it to start and run at half throttle with choke part way. (BTW, these were similar conditions right before the rod threw before) As soon as I released throttle to idle, it died. Upon restart, it fired and then started making what sounded like the same sound as right before the rod threw before; a knocking sound. I'll be pulling the motor again in the next night or two, but any ideas what I should be looking for that might be causing this? Something to check? The cam felt fine when the motor was apart and didn't appear to have any play or unacceptable wear. :(!

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bluecap24
First off I wouldn't put starting fluid in any small engine unless it is diesel. You are drying out the cylinder wall before it starts. Second I would check points gap. Also have you done anything with the carb like clean it or adjust it? If not pull it apart and get some carb cleaner and blow out all the passages. Put it back together and set the needles to the book. You can download a manual from kohler. If you can't get it to start after that check the valve clearance. When you replaced the rod did you check the cylinder wall to be within tolerances? It is possible that after it gets some heat into it there is a crack or it is out of shape and binding the piston.

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Nuzzy
quote:
Originally posted by bluecap24
First off I wouldn't put starting fluid in any small engine unless it is diesel. You are drying out the cylinder wall before it starts.
Really? I always thought starting fluid was specifically FOR spraying in carbs and that it was to be avoided on diesels.
quote:
Originally posted by bluecap24Second I would check points gap. Also have you done anything with the carb like clean it or adjust it? If not pull it apart and get some carb cleaner and blow out all the passages. Put it back together and set the needles to the book. You can download a manual from kohler. If you can't get it to start after that check the valve clearance.
Carb was taken apart (mostly), soaked in chemtool, rinsed and soaked in gas, and then reassembled with a Kohler replacement carb gaskets etc kit. I can certainly go back and reset needles by the book. However it does start, and did seem to run fine before the thrown rod incident.
quote:
Originally posted by bluecap24When you replaced the rod did you check the cylinder wall to be within tolerances? It is possible that after it gets some heat into it there is a crack or it is out of shape and binding the piston.
Cylinder wall was very slightly oblonged, but still acceptable tolerance. I suppose it's possible about the heat, although it really didn't run long enough to get up to any sort of operating temp last night (maybe 15-20 seconds before starting to make that clunking sound).

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bluecap24
What did you set the crank end play at when you put it back together? Is it possible the endplay is too much and allowing the crank to shift to one side and hit the rod. Was there any side damage on the old rod? Does this motor have points and condensor or is it solid state with the little coil pack? BTW... did you use the starting fluid on it just before the first rod blew? Starting fluid is bad stuff for single cylinders. It can blow out plugs, carbs, and even bust pistons. I always use an oil squirt can with gas in it and squirt it in the carb. Of course this is outside and I move the can away before cranking. By no mean is this the safest way, but at least the gas wont dry it out and blow it up. Just a little more thinking out loud and trying to help.

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Nuzzy
quote:
Originally posted by bluecap24
What did you set the crank end play at when you put it back together? Is it possible the endplay is too much and allowing the crank to shift to one side and hit the rod. Was there any side damage on the old rod?
Please excuse any blatant ignorance in my answers as I've never spent much time inside engines, small or otherwise. I never touched the crankshaft during install of the new rod other than to spin the whole assembly when lining things up. In other words, I never had it removed. Can't tell about side rod damage as the thing came out of the oil pan in many many small pieces.
quote:
Originally posted by bluecap24Does this motor have points and condensor or is it solid state with the little coil pack?
It has a standard automotive looking coil.
quote:
Originally posted by bluecap24BTW... did you use the starting fluid on it just before the first rod blew? Starting fluid is bad stuff for single cylinders. It can blow out plugs, carbs, and even bust pistons.
I honestly can't remember if I did or not, but very possibly... I learned something today :I

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Nuzzy
quote:
Originally posted by wilm169
Did you check the crank to rod clearnce to make sure it is not to tight. [Plastic gauge]
Nope. I just put the rod on and followed the torque procedures in the manual. Didn't know there was anything to check after that... Oh how I love learning experiences sm06

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xenon172
Check the crank to see if it is out of round or under size. Also check the crank and cam end play. If there are balance gears make sure they are aligned and timed properly

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