You can get get an indication of a valve being too tight by removing the spark plug, holding your thumb over the hole as hard as you can, and cranking it over. If you can stop air from escaping as you crank, there is a compression problem which may well be caused by a tight valve.

So...you verified spark and with the SF sprayed into the plug hole you got fuel...if it stumbles on SF then you have a compression or timing issue. Do you have access to a compression tester? If not then try putting your thumb over the plug hole and crank the motor...it should "pop" your thumb off...if you don't feel good compression, then could be valves or other top-end issue...

Ok, did the compression test with the spark plug hole, and could not stop air from escaping.

Next step (and continued thanks)?

Escaping from where? That's the point of the test...the air should be getting compressed...


Being a thumper (4 stroke), low compression could be quite a few things...were you using a gauge? What was the highest value registered?

I just did the thumb test, no gauge.

Owning toys requires proper tools. You should consider making a trip to Harbor Freight and get some tools of the trade.

Well, I was just following the directions of one of your fellow commenters. Don't really want to set up a mechanic's shop just to get a new product to actually run. Thought there might be a relatively easy fix, but if not, I'll take it in to a service shop and pursue whatever remedies I have with the manufacturer.

the "thumb" test is a shade-tree mechanic trick to determine if you have decent compression...air should escape because it pops your thumb off...but when read above it sounded like air was escaping from somewhere else...sorry for any confusion...


Thumpers can be tricky to diagnose without the proper tools...perhaps a good service shop is the right path for you...

Ok, thanks for trying.