tecumseh vibration

Hi all,

Bought my early 70s 10xl for a daily mower. Also would like to add other implements. Previous owner (not that he was particularly forthcoming about some of the problems) told me that the engine had been replaced with a rare off-the-shelf replacement three years prior--all flashings and guards in place. Got the thing running and there is a LOT of vibration at full RPM. Previously owned an AC Big 10, so I feel like I know what kind of vibration to expect, but this is insane. Web research suggest that Tecumseh's are bad where vibration is concerned. On the other hand, a guy I know suggested that there is a way somewhere in the bottom half of the motor to properly balance the engine.

Question is, do I try to fix this issue or give up and try to find another motor? If another motor, what kind of luck am I going to have with a newer engine from a different manufacturer?

Thanks for any thoughts.

As an engineer working for a foundry that supplied Tecumseh, Briggs, and OMC crankshafts for years, I can say that Tecumsehs are no more prone to excessive vibration than any other manufacturer's engines. It sounds like that "off the shelf" engine has been rebuilt with non-standard parts affecting the balance or it was intended for an application which had an external baling arrangement.

Thanks for your reply! So you are saying there is no way to eliminate the vibration short of rebuilding the engine? What would you do if you were me?

Thanks again.

Oops, i meant balancing.

Some engines have extra balance weights in the crankcase, gear driven off the crankshaft to cancel the normal out-of-balance condition 90 degrees to the cylinder axis. If the engine has been apart, these weights may not be timed right and that can really screw up the balance big time.

What's really sad is that the thing idles like a dream, very low rpms, very sweet. If I could run it at half speed, that would be ideal. One thing I did notice is that it is much nicer at 3/4--is it possible that it is over-revving when I throttle it up to 1/1? I imagine that would cause a lot of vibration.

Maybe if I can find a reel-type tow mower. My dad uses a big gang mower to mow his field. Seems to work well, but I haven't seen one for lawn use other than the push type.

I have 3 Custom 10 XL's with original HH100 engines, 2 of them are very smooth running but the 3rd one has that HI RPM Vibration I can't get rid of it either. Checked engine bolts etc....re-torqued...no difference.... I saw they had a weight that goes on the cylinder head of some John Deere early 112 models, part # M44631 "TORSIONAL DAMPENER" from John Deere, very hard to find...see link

http://www.weekendfreedommachines.com/discus/messages/335/97078.html?1142615674

Hi: I bought a 10XL which had  a vibration and after much searching I found a cooling fin broken off the flywheel.
To cure it I bent a piece of steel to a U shape to make a clip and placed it on a fin opposite the broken one.
Try to approximate the weight. Mine was a little heavy. But by grinding [ lightening ] the clip and through trial I was
able to remove the vibration. Just a thought.
   Best of luck;          LGB

hi, ten, just a thought  you could check out your local small engine shop or motorcycle dealer,see if they have a wireless tachometer to check your RPM and or OVER REV.  if not, small digital tachs are relative inexpensive on ebay (search tiny tach) 40 dollars or so. and they also have an hour meter. 3600 RPM max for these old engines. a shot in the dark you may check if any of the engine mounting bolts are loose. i doubt it but worth a free look. / tim