Carb on a SS Nelson Quickie

[rocket]

Who’s the expert, how can I do it. I need it to idle and still transition onto the pipe with full power.

[DHG]

Hey, RR. 3 choices here. In order of preference:

1. Find one of the modified ST Mag 4 carbs that Nelson & Shadel used to sell. The throat part has been machined to fit into the front end of the SS Nelson (original, "short stack" version). Those came in 2 flavors, an 8 mm and an 11 mm intake. The 11 mm will tach almost exactly the same as the regulation 9 mm black plastic air valve that Nelson supplied with the Q500 engine. Not all of the 11 mm can admit air because of the spray bar running through the middle of the hole, so it needs to be oversize to match the flow rate.

2. Find any other throttling carb that will fit. I think one of the large O.S. pattern carbs is the right size. Jim Allen may know which one to use.

3. Take a Nelson black plastic air valve and drill a small air-bleed hole in the front so, when it's closed, it doesn't get rich enough to choke out and die. This is a crude solution and you may not get it precise enough to idle indefinitely, but it should be sufficient to stay running at a medium to low rpm for long enough to handle a missed approach or fly around slow for a while. IIRC I've used an .032" drill bit to get fairly close.

I hope this helps.

Cheers,
Duane

[Greg Doe]

OS 7M carburetor has to be modified. I believe it's a helicopter carb, because it has mid-range adjustments. Shadel did one for me. You can try it, or trade for a OS 60 carburetor that will work in my now worthless donor engine. Once modified it will no longer work in the original engine.

[craigfarthing]

Dub Jett sells a carburetor for his 426 motors. Mine fits into a Nelson shot stroke. You might talk to him.

[realviking]

I have a Nelson with a Super Tigre carb. I bought on E-bay but I do think it came this way from Nelson

[rocket]

Have you run it?

[GaryS]

There was a time that you could get an ST carb on a Nelson from Shadel. I'm guessing that Ola's may be one of those.

Also, several Control Line Carrier guys run Nelsons with carbs on them.

[realviking]

I have not run the Nelson but here is my DKT Pylon Engine with Carb.
Idle and throttle response like O.S. Speed like a 428 Nelson.
The carb is a modified Evolution .40.

[David Ford]

Jim Allen wrote about his Quickee Nelson with an OS 7d carb. Look on RCgroups - Pylon- The way we were - pylon nostalgia way page 56, post 816.

[Speedfreak1]

Hi Rocket Ray! This is Kurt Beachler.
Here is a video of mine running with one of Dub’s old carbs.
https://youtu.be/3o37tIS_VI4
Runs perfect!
Kurt