venturi size

What size venturi would work well on a Merco 61 using an ST needle valve?

You can pick your nose but you can't pick your relatives.

>What size venturi would work well on a Merco 61 using an ST
>needle valve?

If you are running the needle through the middle of the venturi, then try a .312 to a .323

Thanks. Any suggestions as to prop size?

I use a 0.250 hole but no spray bar. Fuel is delivered via a Enya r/c spray bar that sticks in the side, just like an r/c carb. I run a 12.5-5.5 3 blade carbon fiber. Also, that Merco is bored to 0.64.
For my Merco 61's, I run a 0.285 venturi and Merco spray bar, 12-6 2 blade, a Top Flite paddle blade. Or a 0.300 venturi and 13-5 of 13-6 Rev-up. I use 10% Nitro, 20% oil, most flying at sea level.

I'm using a tall .310 in my .61 with the black screen in the filter and ST nva thru the venturi. It's currently swinging a RevUp 12/7 2-blade.

I have 2 Merco .61s. The firstv one was set up by Tom dixon .285 " venturiuses a 12-6 wood prop .The other was setup by Georgr Aldrich it uses a .316 venturi swings a 12-6 or a 13-6 Top Flight . A very docile engine.
John

> I have 2 Merco .61s. The firstv one was set up by Tom
>dixon .285 " venturiuses a 12-6 wood prop .The other was
>setup by Georgr Aldrich it uses a .316 venturi swings a
>12-6 or a 13-6 Top Flight . A very docile engine.
> John

John;

Interesting.

What is the performance difference between the Dixon setup and the Aldrich setup? Just as a point of reference, I run a .285 venturi in an Enya 45 (6001). It sounds as if the Dixon setup is starving the engine, but he may have it set up differently.

Bob,
For some reason anything I got from Tom was what iwould call a small venturi but they allways pumped out the power used less fuel.
John