I'm working on a 4 star 40 onto which I'm building a cowl. It would be of benefit to this effort to move the needle valve from its current position (about 2" from the carb on an OS .46LA) to a position in the fuselage that might be as much as 8" from the carb. What is the effect of this? The benefit would be solely in sanding the cowl to shape and reducing the opening equired in its side for engine insertion.

TL
Athens, GA

Does not sound like a good idea to me. You will have a long delay for any needle valve adjustment you make and all of that extra fuel line will hurt fuel draw.

I agree with Dsegal on both counts, however, the crappy plastic assembly on the LA will break in a heartbeat on "face plant" landings if it is attached to the engine & poking out through a hole, or slot. If you can move it closer (firewall?), you will likely save the expense & bother of frequent replacement, at a minor penalty in adjustability (fuel draw will be OK with a firewall mount).

In an attempt to disagree with the others ... ;-)

I DID faceplant an OS46FX. I broke the flange that the some-what remote needle lives on. The needle itself was fine. I relocated the needle to be part of the cowl about 1inch further back on the plane than the original location. The big difference is that the location requires the fuel line to be about 3 inches longer than the original between the needle and carb.

Tuning the engine does not appear to be a problem. It runs just fine, and pulls a pattern plane very stongly. i.e. I do not notice any problems with tuning the engine at all.

See the pic.

gus

The line could be 100 feet and there would be little delay. The only effect is that the longer line would be more restriction. However if you can open the needle up enough to make up for this restriction their would be no differance.