RCU Forums - O.S. .40 four stroke issues

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O.S. .40 four stroke issues

I picked up an O.S. .40 four stroke at the swap meet. It has the exhaust stack (no muffler), and a fitting
on the back plate that I assume is the tank pressure.
I can't seem to get it to start. It draws fuel, but won't fire. The plug is good.
What next?

RE: O.S. .40 four stroke issues

Quote:

ORIGINAL: skyraider71

I picked up an O.S. .40 four stroke at the swap meet. It has the exhaust stack (no muffler), and a fitting
on the back plate that I assume is the tank pressure.
I can't seem to get it to start. It draws fuel, but won't fire. The plug is good.
What next?

Not tank pressure - breather . . . . I have never seen an OS that ran tank pressure that way - that's pretty much a YS exclusive . . . . .

As to your problem, have you checked the valves for clearance and seal? And above all else, lose the breather to tank connection - the breather should just dump overboard, and you use muffler pressure . . . .

- Tim