My Linhai 260 ATV was running great, started right up. Then all of
a sudden it started bogging down and cutting off. Now it
will not start at all. I have spark but it will not fire even
with starting fluid. I am thinking the valves need adjustment? Could this be the case?

 

Check compression and report back.

 

Good compression. It blows my finger out of the hole

 

It has a white spark. Is that a sign of weak spark?

 

Not a very good test. Buy a compression gauge at your local auto parts store. Some places will even let you borrow one.

 

Before spending money, adjust the valves and clean the carb out.

 

Any idea what the thread size is on the spark plug. Only tester i can find for a loaner has an 14 and 18 mm adapter.

 

Wouldnt it at least fire with ether if it was the carb?

 

I would bring the spark plug with you.

Also, Harbor Freight sells a compression tester kit for about $20. It has multiple adapters.

Compression Test Kit 8 Pc

 

Well being out in the country its a 1/2 hour trip is the reason im asking.