swank

After using OS engines for many years, just for grins I've decided to try a GMS .76 engine for my next project. I'm curious about your opinions on the front needle valve vs. the remote needle valve setup.

Other than keeping your fingers away from the prop, are there any advantages to the rear needle valve setup? I've had other engines with remote needle valves and always felt that I couldn't fine tune them quite as well as when the needle valve was directly in the carburator. OS has retained the front needle valve design in the AX series (except for the .46AX) which leads me to believe that the front needle valve is still a better way to go for tuning.

So what do you think . . remote needle valve or front needle valve . . opinions please!

estradajae

You've said that....not to mention that it also eliminates thousand of possible problems with the remote installation..like leaks, bubbles, and like on the 91FX with an older design...tunning problems related to heat....

Hobbsy

My Feedback: (102)

Swank, since fuel will neither stretch nor compress it doesn't matter where the needle is, I like the remote ones. All my MDS engines have them and some my others have MDS remote needles on them. If using a Cline regulator I use the MDS remote needles because they will leak when under pressure.

wcmorrison

My Feedback: (2)

I have even seen a couple of remote needle valves just dangling in the breeze and a few mounted on the fire wall. All seem to work with out a problem. Like the man said, the fuel is not compressible, so where you regulate it is not a big deal.

Cheers,

Chip

blw

My Feedback: (3)

people tack the remote needle valve somewhere on the firewall after a crash when the bracket broke at the backplate.

hugger-4641

My Feedback: (6)

Not always the case, On my Avistars I mounted all of them on the firewall because I teach a lot of people how to fly and its safer to operate when located there. The down side is it creates another opportunity for leaks in the system. It also adds a slight delay in mixture adjustments, but not much. Otherwise, I don't think it really matters much where you put it. Just my opinon though.

Skratchbilt

My Feedback: (6)

I believe, that with these other's opinions, the main reason for rear, or even remote needle valves, is the engine mounting configuration. In my case, to avoid unneccessary butchering of the sweet cowl, a rear valve was used to make for a cleaner application.