Hows your fuel tank? Igniter fully charged? When you tip the car to the side does fuel pour out the pipe? I had a broken fuel tank and i had a similar issue. The tank would hold pressure and would weep from the seam but some how the fuel system was over pressured and dumping fuel in the motor

The tank was new. It only has the 2qts that I have ran through the motor. Can different pipes change the tune of the LSN? I have a 021 manifold with 9886 pipe on it now. I do have a new 9901 pipe as well. Maybe I just need to lean it out more on the LSN. It just seems like I am leaning it out a lot. 3-4 turn in from flush. Maybe I’m just over thinking it

You’re probably getting some things mixed up. Always start rich and work lean. Ignore how many turns in or out you are - the engine doesn’t care how many turns the needle is as long as it’s in the butter zone.

Easy method to tune - start out fat on both needles. Start with high speed and get it set satisfactorily. I recommend to tune to peak (perfect transition from idle to WOT) on the high and then once set work the idle. Get the idle set where it is slightly loaded up after 10-15 seconds of idling and a nice easy cleanout. Now go back to the main needle and adjust it a tiny bit richer. When your idle is set correctly, it should drop a degree of temperature after every couple seconds during a longer idle.

What’s the idle gap? This one setting could screw everything up if not set correctly.

Try going to .5-.6mm if the engine has some time on it. I set my engines to .5mm from new and adjust from there. Usually they end up being happy in the .5-.6mm range.

You should also make sure you’re not trying to get a solid tune on it until you have at least a whole tank through the engine so it’s thoroughly heatsoaked. If you try to tune it too soon, your tune will be off because the engine leans out a little bit as it heats up.

there is no such as thing as a standard setting with idle gap , lsn ,hsn settings on any engine.......

your cars fuel system and the fuel you use (mostly oil package) will depict how your needles will need to be adjusted more than anything .... period !!!

you will learn through trial and error for the most part

all different manufacturers have different materials they use with different rates of expansion and it greatly affects how the engine will need to be tuned ..... there are sooooo many variables its ridiculous


happy motorin'

It’s been very common to me in helping others to get their engines running properly where they have difficulties getting a good needle setting and finding the problem stems from an improper idle gap. For this reason I always recommend starting tight and working wider to find the sweet spot for the same reason one would start the needles rich and work lean on the needles. I’ve also found that an engine that isn’t thoroughly warmed up will almost never hold its tune and will usually end up being lean.

Just my experience. YMMV.

well most racers who dont understand the mechanical workings of a 2 stroke mini diesel vacuum pump using a tuned expansion chamber to adjust powerband usually leaves the low speed needle wayyyyy too rich so they adjust idle too large .... i agree it is an easy way to get someone in the ballpark by telling them to adjust idle gap to a certain setting .

I can see where my advice could be construed as “put it there and leave it there”, but that isn’t how I meant it to come across. My settings are initial only as every application and engine is different. Just to be clear.

And for the Ricky Bobby type RC Racers... Don’t run a super fat idle needle. Or a 1mm idle gap. You will probably have problems. LoL.