Sure it not Vibration???????????

That could be RC , pretty ore afterwards.TY... but is there a ground strap?

I always thought that ground straps were used to prevent the build up of static electricity. I remember back in the 1960's people would put clear plastic seat covers on new cars to protect the upholstery. The trouble was that sliding over that plastic would build up a static charge in your body and when you put a foot on the ground you could really get zapped. A ground strap on the car would prevent that from happening. And no, the tractor doesn't need a ground strap to help it start, or run, so there is not one on it; the negative pole is on the battery.

A huh! John thats it the JD slip over seat cover , it does move around on the foam seat , so that must where be the static feeling is coming .My left leg after an operation is very sensitive after 6 years still, that does not help either, but the mower sure does TY John. Pete

I experienced "static electric shock" one time in the past while using a Craftsman "Shop Vac" to pick up sawdust from the floor and machines after doing a wood working project. This was at a friend's house and his shop floor was concrete. It startled the heck out of me the first time it occurred, I actually thought I had "hit a live wire" or something. After confirming that there were no exposed wires anywhere that I might have touched, I resumed vacuuming. A few seconds later, zaaappp! again.
I said to my friend, "This thing is biting me." He said (with a knowing grin) "Getting the shock treatment are you?" I said, "You knew?" He sort of chuckled and said, "Yeah, it got me too." Then he took a length of small galvanized chain (like the utility chain that you hang shop lights with) off of a hook on a peg board and said, "this is what I came up with to stop it." He had made a loop in one end of the chain by unfolding the end link and then hooking it into another link and rebending it. He draped the chain loop over one of the "caster wheel towers" on the canister so that the chain could drag on the concrete floor. This ended the shocks (I think he "set me up". The static electricity is apparently generated by the "rubbing" of the wood particles against the plastic hose and the plastic collection canister as the airflow moves them along. Being as the entire unit is plastic (including the wheels) the canister and hose probably act like a simple "Van De Graaff" generator and capacitor. The stactic charge builds to a point where it has enough potential energy for a spontaneous electrical discharge (think...high tension spark). If YOU just happen to be "the path of least resistance", you will definitely "notice" the "capacitor discharge". I speculate that the DR vacuum rig uses a plastic (or possibly rubber compound) for the pick-up hose, and a plastic cover for the cart....capable components for a "static generator" AND "storage capacitor". I'm not
certain if this phenomenon is the culprit or if it is the "seat cover". I presume you have had the seat cover in place for some time and DID NOT feel the electric sensation until you began your DR vacuuming. You might try something similar to what my friend did with his shop vac. Get a length of small utility chain and drape it over the metal tongue of the vac cart so that both ends of the chain drag the ground. I suggest that you don't attach this chain TOO securely (in case a link somehow snags something) but instead just "tie it together" with a small piece of wire or paper clip. This should be easy enough (and cheap) to try.

What you are describing does not to me seem like static electricity. I don't want to alarm you but it sounds more like a pinched nerve.

More like nerve damage which why I walk with a limp. Tho will being testing this chain tneroy soon. ty cheers

Well back to report , hooked a small dog chian up to frame of the vac to the ground and that static is gone. TY mowie. Done for the season. cheers

I'm glad your electrifying experience has come to a sparkling end.