well i just rebuilt my engine in my 1650 and did abunch of general work up front. i fired it up today and had some anoying rattles still so far this is what i found and the hood and grill is not on yet. my throttle cable was hitting the hydro linkage arm. i put some plastic split loom over that. i still had a rattle but when i pushed in on the end of the hydro lever it went away. well when i had things apart i took of teh link going to the spool valve and cleaned it all up. it seems all the gunk and rust was keeping it nice and tight. now it is free and is clattering around. i think i will throw some grease on it and it should quite it down hopefully.

Is the noise something new? If it is I'd start looking for things that are loose and remove them one by one and see what happens. The other guys have given you some good ideas to check.

Yep, lots of things to look at. I really hope it's something simple.
Dave

I would check the engine tin,like the muffler tin and ISO mounts. Could be a loose muffler clamp too. My 1200 was rattling like crazy had some bolts on the muffler box that worked loose.

I would be concerned about piston slap too. Of course weed out the other things like tin vibrating, etc. too.

Good luck,
Bill

My 108 started making a metallic knocking noise. pulled the head to find a scored cyl, and lots of fine aluminum in the oil. And badly worn piston skirts. It did start to blow smoke out the breather. It wasn't really smoking out the exhaust like it was burning oil at all.

My plan so far is to check all the easy, visible stuff and if I don't find anything there I'll go into the engine. I've got my fingers crossed that the engine is ok

I have a freshly rebuilt 1450 .030 over, new piston & rod that makes the same noise. Really worried me at first and was told they all do it. While the engine was out I did the axle squeeze and ISO mod w/new factory mounts.

My 1250 w/unknown hrs makes the same noises.

Rec'd a lengthy reply from a gentleman in WA state who is a retired machinest.

He stated he had one w/the same problem and set out to find the source.
Seems as though these Kohlers are not all that tight on the tolerances when new. He found that the cam shaft ends and pockets in the block were not true. After lapping the block surfaces, trueing up the cam ends and shimming,
it eliminated the noise and stated he has done at least a dozen engines since and that procedure cleared up the noise in each case.

Dave S.