dork_blaster

My Feedback: (14)

Before I begin, let me say that I've been very happy with the three of four motors I've purchased from RCS (RCS130, ZDZ80RV, ZDZ160, ZDZ100NG), and that I've had enough experience with the other three (and my other gasoline motors BME, DA) to know that something is amiss with my ZDZ100NG.

Background on the motor: bought new March '05 about 3/4 gallon of the break-in mix 1:32 non-synthetic 2-stroke (Penzoil), 26x10 Bambula, JMB silencers. Idle screw 2 turns backed off from full closed, plugs cleaned and gapped .022in, Hall sensor 6mm spaced from TDC, ignition power comes from 5.1V reg fed from Duralite LiPos.

I have 3 problems, two are major irritations, the third I hope will go away or is symptomatic of the first?

1) Starts and runs okay cold, but I need to prime (2-3 flips) to get her to fire warm. I NEVER had to do this with my other gasoline motors (expecting 1 or 2 flips warm and NO choke to start).
2) Carb leaks quite of bit of fuel when it runs, pools at the bottom of my motor box to the point it gets all over the inside of my cowl. Luckily I have holes in my motor box floor. Tightened screws that hold the diaphrams and carb to no avail. My other motors spew fuel from the venturi, but don't drip like this one does.
3) At low RPM transitions (just past idle to about 1/3 throttle), the motor goes from what I describe as a nice, low vibration hum to intermittent "growling" with lots of vibration.

I would guess I have a bad carb?

Thanks in advance for any help Mike!

Mike Dooley/RCS

Check that the metering fork is engaged with the nipple on the diaphram, if not it will cause the engine to always run excessively rich. Please remove the diaphram cover and carefully remove the diaphram to be sure it is engaged properly.
Also be sure the carb is getting cool air and not getting overheated.
Also, check the throttle butterfly for 2 small holes approx 1/32" in dia., if these holes are present, solder them closed.
Please keep me posted, we will get this resolved for you.
Thanks,

dork_blaster

My Feedback: (14)

Thanks for the quick response, Mike. I will check the things you suggested this weekend.

dork_blaster

My Feedback: (14)

Hi, Mike - tried all your suggestions and no change. What's the next step?

dork_blaster

My Feedback: (14)

Well I replaced the carb with a new one which doesn't leak but it was still hard starting warm. Removed carb gasket and low and behold, all kinds of some sort of silicon-like sealer plugging up the pulse hole and channel/ring that feeds it. Cleaned it out and she starts, runs and transitions like my other motors, real good!

Mike - please let me know if I can get a swap or credit on the old carb.

DB