Break In Proper carburetor tuning during break in.

[wan37]

(Seal all) That stuff even helps with the vibration . I heard of carburetor vibrating off which could be bad. So it holds it on too .

 

[Axl Myk]

First thing you need to do is stop using 20:1 mix. All that is good for is getting oil all over your shoes.
If you have a lawn tractor, or even a car, dump what you have in it and mix some 32:1.
Put the needle clip in the middle, or the second notch down if it has 4 notches., if you have a jet kit put in a 68 or 69 jet.
Run it a few times.

 

[mcdanida]

The needle is at that location now. Son said it ran pretty good. The 32:1 mix is next. Break in is done.

 

[Vwiz]

150 miles is well past break-in stage. Switch to 32:1, then clean the air filter, or preferably upgrade it to one that isnt restrictive (won't effectively choke the engine at high RPM).

Having the needle dropped one notch below the middle won't do any damage. Actually, it is the most common needle setting.

You might want to get a smaller jet but I would wait until you have a great air filter first so you can see what that does.

 

[Vwiz]

If re-jetting means relocating that little pacman clip on 1 of the 4 or 5 slots on the needle, I am leaving mine near the top where it is for now. I cannot complain getting 35 mph with some throttle left.

 

[yuckfoo]

If anyone is still following this, I am using 32:1 mix now and wondered the best carb pin setting! Closer to end (lean) or closer to middle (rich)? Thanks!

Running rich is always safer than running lean. Checking your spark plug color could probably help you determine what you need to do.

 

[Shawnandkate8]

I know it’s an old post but just found it. Sorry. Still in break in period. Engine seems to run strong got 39 out of it on second ride. Wanting to tune the carb a little as its four stroking some and I’m really not to sure why. Seems fine and snappy under load but at cruising and towards the top end not under load gets a bit 4 stroke sounding. My question is I have ordered a fine tune jet kit but haven’t adjusted the needle at all. Should I start there before re jetting or just go with the new jet size? I’m of the opinion on to do one at a time and test but wasn’t sure where to start exactly. At sea level with stock 44t sprocket. Any suggestions?

 

[DAMIEN1307]

My question is I have ordered a fine tune jet kit but haven’t adjusted the needle at all.

Ive always started with this first so i think your thinking is ok on this.

Where is the "C" clip located right now on the needle valve...On the stock NT carbie there are 5 different positions it could be in...your at sea level so yours obviously does not need to be where mine is as im at a 4500 ft above sea level locaton in the high deserts of New Mexico and im always climbing to higher elevations, so my "C" clip needs to be at the very top of the needle...So let us know where yours is right now and we can tell you where to try it from there...DAMIEN

 

[Shawnandkate8]

Will do. As soon as I get home and get it opened up. Thanks.

 

[Karl Snarl]

Will do. As soon as I get home and get it opened up. Thanks.

These engines will always 4 stroke a little when tuned properly, at cruise. If it doesn't do it a little, you are on the edge of to lean. Now a bunch of 4 stroke is either a new engine breaking in or you need to get the jetting and needle right. If it is from idle to 3/4 the problem is, you use a needle, if wot, its the jet. If you can get the bottom set in right but it 4 strokes at wot, you play with jets. If you can dial in wot and the bottom is finiky, you play with the needle.