[SEL] Hidden fuel filters

[Rob Skinner]

>   I know some of you build your own checkvalves. 
> Does anyone have a diagram or schematic (with possible
list 
> of material) for 
> small check valves for small engines?

Hi Francis,
I've made them from tubing fittings (see attachment).  Find
a ball that is larger than the ID of the tubing, and that
won't fall through the fitting.  You can hand lap the
tapered inside of the fitting, but most already have a nice
enough finish.  Put the ball in the fitting and blow down
on it.  See if it seals or needs more lapping.  Don't
inhale the ball.

Next, without the ball in place, assemble the compression
fitting with the tubing, you don't want the tubing to
bottom into the fitting.  Take it apart, stick the ball in,
and carefully reassemble.  If the tubing bottoms out on the
ball, take it apart and shorten the tubing protruding from
the ferrule.  Keep reassembling until the ball will rattle.


Now take it apart again.  Notice that if the ball is pushed
UP against the tubing in direction of fuel flow, it will
seal againt the tubing, preventing flow.  You need to notch
the end of the tubing with a triangular file.  Put about
four substantial notches into the end of the tubing.  You
can balance the ball on the end of the tubing and blow
down.  Make sure you get some air flow.  Again, you run the
risk of swallowing the ball, which is why you should have
bought two in the first place.  

Brass fittings are nice, brass balls are nice, stainless
balls are nicer, steel balls will rust.  

Rob


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Rob Skinner
La Habra, California
www.rustyiron.com