OS 30 FS manifold?

Does any body make a c/l intake manifold/NVA for the OS 30 FS?

I know it doesn't answer your question, but to first order, simply wire the carb open (or to whatever position you need). It worked fine for my Saito 30. Bill Calkins had an elegant example that he used on the OS20 (or 28) FS that he put on his CG Shoestring. There is a picture somewhere in the archives.

added: here is the link

http://www.clstunt.com/cgi-bin/dcforum/dcboard.cgi?az=read_count&om=2984&forum=DCForumID1

Try Jim Carpenter in New Hampshire. He makes venturis for the .32FS I believe. Contact him Tell him Joe sent you.
Joe Just

Our host has these and specificly lists them here:

http://www.clstunt.com/products.htm

I thought we were talking about the new OS 4-stroke (maybe I missed this). If so, I don't think Leonard carries these items (also could be wrong!).

actually I was asking about the OS 30 Four Stroke... The "problem" is that the R/C throttle and intake manifold are a single casting. There doesn't appear to be a easy way to replace just the R/C throttle. And I've had less that satisfactory results just fixing the throttle full open...

Ron,

I guess my question is what those less than satisfactory results were.

One has to remember that these carbs were designed to run with muffler pressure, so the fuel draw may be less than optimal without pressure. The cool thing about using muffler pressure is that the engine can run in reverse, with the muffler becoming the carb, and the (real) carb becoming the exhaust. This can make a real mess in a tight cowl configuration. This is one good reason to use an electric starter!

Yeah, got the muffler pressure hooked up...
The problem is unsteady rpm in level flight, on the ground, on the bench it will wander + or - a couple hundred rpm. and it won't hold a setting: some times it will go rich, sometimes it will go lean during a tank of fuel.

...and I thought the beauty of four strokes was the consistancy of runs...

>Yeah, got the muffler pressure hooked up...
>The problem is unsteady rpm in level flight, on the ground,
>on the bench it will wander + or - a couple hundred rpm. and
>it won't hold a setting: some times it will go rich,
>sometimes it will go lean during a tank of fuel.
>
>...and I thought the beauty of four strokes was the
>consistancy of runs...

Lots of people have noted this phenomenon.
The carb is probably the cause, and the solution is to use a regular venturi.

Which brings us full circle...

There is always the razor saw! --and a drill press to get a spraybar through. I haven't seen the OS 30, but I bet one could machine an insert (plastic maybe) for the carb barrel for the Saito. Haven't looked that close yet.

In actual fact, most of the guys who have played around with the smaller 4 strokes (40 and below) around here have had no problem with simply wiring the carb open. I also have never noted a problem while running them full throttle in RC applications (like surging or ....)

If he is having draw problems, I wonder what size prop he is using. An oversized prob reduces the airflow velocity through the carb and might cause fuel draw problems--if that is the problem.

Haven't tried it yet but wonder how close the UHP Saito-40 intake is to the OS-30. I have a 30 and one of the UHP manifolds but finding them may be a bit of a challenge.

Pat Johnston fixed his Saito .40 by turning an aluminum plug that pressed into, & fills the bore vacated by the throttle barrel (the thingy that rotates). A hole through the center fits a standard .156" spraybar. Then drill down through the carby "venturi" bore, in an appropriate size. In the case of a .30FS, I'd think something like 7/32" would be a reasonable starting point (definitely on the small side). Steve