mixture settings on nitro engine

[apache480]

I am just about ready to crank my latest project which has a picco .90 in it with a remote mixture setting instead of on the carb. I need to know where a good setting to start with on the needle would be. I also have a few other questions about this engine.

1. how many different variations of this engine did picco make?

2. how do I tell which one I have?( I know it's an older one)

3. where can I find parts for it if they're still available?

thanks, Jeff

[engineman351]

Jeff, If it is has a 'hex' head (six bolt) it has been around since the '80's with only suttle changes over the years. In the early 2000's Picco introduced a newer model (XP?) that has a smooth head. Unfortunately distributors for Picco have come and gone in the US, but I see some NOS on e-bay quite frequently. If you can afford it, an extra piston/sleeve and rod is always a good bet. BOCA should be able to match up any bearings that need replacing. Remote needles aren't usually an issue, since they normally just move the needle off the vibrating engine and therefore keep the fuel flowing more consistently. If you are running 25% or less nitro, I would start 4 to 4.5 turns out from stop on the main needle. The more nitro you run, the more you will have to open the needle. Whatever setting you start with , you want to have the engine so rich that it sounds rough and maybe even labors a bit to develop enough power to get on plane. From there, keep turning the needle in an eighth of a turn at a time until the engine sounds clear and crisp when you are at WOT. If the engine stalls after you accelerate and the engine is revving pretty good...always richen the needle first before trying to lean it. Once you get a good needle setting, check what it is, and write it down, noting weather and temp for that day. After writing the setting and conditions down for a few different type days, you will have an idea which way to go. (FYI ususally: colders days you can run richer..hotter days you need to lean it out a bit). If you know anyone with a 'flow meter' pick their brain!! Good luck. RC