Just been trying to set up a new SC120 4 stroke for my son in a P51.
Had a few tanks through it now and it seems OK but I'm a bit worried
about the needle valve setting? It will only run OK with the needle
about 1 turn open. Is this right? I always thought it should be about
2 to 2.5 turns. We ran it in at about a 5 turn setting and have slowly
closed this down as it ran in. Idle is fine and it seems to go to full
throttle fine but changing the needle valve doesn't seem to do much at
all. I've only ever set up 2 strokes before and I know on them that
setting the needle valve changes the engine speed quite a bit.
18 years ago