05 F250s Sticking Rings?!

Hey

We've just rigged 2 05 F250's with 1300hrs onto a 36ft Contender. The motors hadn't been ran for approx 12 months, Over the weekend when we ran the motors occasionally there would be a puff of blue smoke from the port motor. We also noticed oil leaking from the crankcase vent hose. Does anyone know what this could be caused by?

Also what is the best de carbonisation process for this motor, i.e a shock treatment of ring-free or something else and whether it'd be best to run it through the fuel system or whatever. I heard a 2oz to 1Gallon would be good for a shock treatment with ring free.

Please help
Thanks

Yamaha has a decarbonizing product "YIEC" , used as directed it can do amazing things. Other than repair a mechanical problem. Worth a try.

You really need to do a leakdown test on the engine. That will tell you exactly what shape your cylinders are in and help troubleshoot any problems. Your blue smoke could be from an over rich mixture in one of the cylinders.