hosam

My Feedback: (121)

Guys, I need you help on this one really bad... My new 2 stroke motor seams to run at its best (and I do mean best) is when the high speed needle is fully closed and will still continue to run at full throttle and idle with no issue... And yes it is gettign hot, so what gives? please help

Thanks
Hosam

tail strike

My Feedback: (1)

Sounds like it is sucking air.
Thats my opinion, if you don't like it I have others

AA5BY

It has to be getting fuel so it is an illusion that the needle is closed. The needle is either binding somehow to cause it to feel closed or there is something in the needle body that is restricting the needle from closing. Whatever it is, it may not be allowing proper adjustment. If running its best means max RPMs then that is too lean and hence why it gets hot. Depending on the engine, almost all engines have to be richened and run less than their max rpm so that the engine runs within a temperature zone that doesn't break down the oil and cause lubrication failure. Glow engines also dissipate some of their heat in the raw fuel and oil discharged from a slightly rich setting.

At the minimum, remove the needle valve and hook the fueler hose to the vent line (with fuel in the tank) and hit the pump for a moment to flush the needle assembly. Examine it carefully by shining a flashlight into the carb throat and looking down the needle shaft. My guess is that there is a sliver of fuel tubing stuck there. All brass fuel couplers should be sanded slightly to take the sharp edge off that might slice a sliver of fuel line leaving it to contaminate the needle valve or carb.

Another tell tale sign of a contaminated needle is if the engine will not richen up when backing off the needle.

rcdude7

My Feedback: (264)

The needle you have may not be the right one for that carb. A needle that is fully seated should close off the fuel supply completely.

You don't mention the engine or carb you have, it would be helpful.

pe reivers

The idle needle provides fuel for both idling and high speed running. The high speed needle becomes active at about half throttle (more or less)
So if you open the high needle, you need less idle needle for the best full power mixture. The trick is, to find the best balance.
The mark of a lean idle needle is, that the engine becomes hard to start. So find the point wher idle rpmis best, then open the idle needle 1/4 turn, and adjust high needle for best power, on the verge of dropping off in rpm when opening the needle further.
\then check engine behaviour. If it starts well, and midrange burble is acceptable, you are set up ok. If this burble is too much, try out a leaner low needle, and open up the high needle to compensate. If now starting becomes cumbersome, go back to previous settings and accept the midrange burble.