Sherv

My Feedback: (1)

I'm used to nitro and monitoring the temps to stay at around 190-200 idle and 250-260 under load. But I'm a newb when it comes to these gas engines. My nutech MMT has been cutting out mid tank a few times and when I inspect it i noticed tons of bubbles in the fuel line and It takes a while to start but when I checked the temps the second it cut off I was reading 269F on the fins. Is 269 too high? This is on Grass (which I know causes a lot of stress) climbing hills for 5-10 second full throttle bursts and 5 second 1/2 throttle. I checked the spark plug after 2 full throttle passes and its color is tarnished/brown color but near the ignition/spark spot its got a dry black residue, none of the white stuff that indicates too lean (is this right?). When I let the engine idle from a 270F temp reading it drops to 230-220F within 10-15 seconds. It never gets above 250 on asphalt full throttle for 20 seeconds.

I have a theory on the half/below half tank engine cutting off issue... When I approach the car immediately I noticed lots of bubbles in the fuel line and I notice the cap for the tank is fizzing/releasing gas/bubbles. Would it be possible that pressure build up in the tank would cause air to be forced into the fuel line during take off/landing/bumps?

dealwithit

My Feedback: (55)

hmmmm i have a new FS buggy thats doing a very similar thing, running wise. it seams like its leaning out, so i richen the low end abit and it starts going better. then after a couple mins at that it starts running to rich so i lean back out abit and it starts running good again. i wonder if the tank isn't venting properly on yours, causing a vacum in the tank (if its running the tank cant really pressurize because its always sucking out fuel)

clubin

Make sure the clunk fuel line is long enough- it might have gotten pulled on and the clunk might not be sitting on the bottom of the tank. , and maybe add a Zenaoh clunk.

Temp is not a way to tune these 2 strokes. Tune by sound, and plug color.