My first installation of a four stroke and I was wondering about the fuel
>line set-up. I have an OS 70, Surpass and it has the muffler pressure line
>and the carburetor connection plus a line that comes off the crank case at
>the bottom. What is this third line for?
>
>Thanks in advance.
>Todd
>
It's a crankcase vent that will carry half-burnt goo out of the engine...If the engine is enclosed it's a good idea to run a line off this vent to the outside of the fuse...
Droolage. Actually it is a crankcase breather and you will need to attach a length of fuel line to it and out the bottom of whatever plane you are putting it into. It allows air to move into and out of the crankcase but WILL drool out a bit of oil/fuel. Its main design is to prevent a vacuum or pressure situation in the crankcase that would interfere with the fuel/air mix draw. I have a newer Surpass II and that line attaches to the carb draw tube same as the crankcase breather on your car.
It also serves a second purpose which is to route the blowby oil to the cam and followers.
Thanks everyone, that helps a great deal.
Todd
Todd, It's a crankcase vent or it can be used for a fuel pump. Just run a line to the outside of the plane.
Happy Landings, Mike
I have an OS 40 Surpass with the same crankcase nipple.
The instructions say that any tubing connected to this should not exceed two inches or it could prevent the breather doing its job and do harm.
Malcolm
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