Should I bother giving it gas 1996 Yamaha vmax 600 xt snowmobile how to id problem?

[t#$%@&]

I got this sled with trade and I guess with all my auto experience I have never had so much trouble as I do with this one. First mistake was putting Valvoline Tw-3 in it because the oil light was coming on and off then let my daughter ride it for nearly an hour slow around the house 5-25 mph. When I got back on it right off I notice it to fall on it's face when it otherwise would come unglued. Although this sled just rolled 9990 miles I suspect it is still the oil causing the problem. I had used a pump and drain the oil tank then added 2 qt of Castrol 2T assuming ly the other Valvoline oil was to thick. But did I simply put tw-3 back in? It seems to have fouled a plug after a easy 1 mile ride. It will start to come unglued right now then fall like lack of lubrication. I am not even sure what octain belongs in it nor do I know if the oil injection pump went bad. When idleing for a few then trigger the throttle to that point it starts to breath again for about 1.5 seconds then boogg and top speed around 35-40 maybe. If I had a cylinder pressure tester I would check it but it walked off with someone.
Your experience will be my gain and hopfully save what was a good running sled. And give reason to change the track cause I hate to have to sell it.

 

[guardrailjim]

The oil light might have been from a faulty sensor - check the tank next time the light comes on.
Tw-3 oil shouldn't hurt the engine.
If it was to thick, the engine would constantly foul the spark plugs.
Lugging the engine will foul the spark plugs.

Check the air cleaner.
If you're unsure of it's condition, temporarily remove it and run the engine to see if it makes a difference.

To check the cylinder compression without a gauge - remove the spark plugs and press your finger over a plug hole.
Pull the starter cord - there should be enough pressure to force your finger off the hole.
If one of the cylinders feels stronger than the other, that would indicate a top end problem.
Regular unleaded gasoline is fine.

If the oil pump was bad, the engine would lock up due to lack of lubrication.
To check the oil pump, remove the oil line going to the engine and pull the starter cord a few times - oil should come out if the pump is working.

If you're concerned about the condition of the top end, remove the exhaust pipe & flange from the engine, then look into the exhaust port with a flashlight & mirror.

Since you got it for free, why not take it to a shop for an estimate?
If it costs to much for them to repair it, you'll have an idea of what's wrong and then fix it yourself.