My Zenith on the 2180 VW does go rich to lean from idle to WOT. I have a Mixture Meter that shows this in real-time and can dial in the mixture from the cockpit as needed. The knob in the cockpit is connected to the needle valve on the carb by a VW speedometer cable. As far as I can determine, the Zenith I am using has only two jets: an idle jet with a screw adjustment and a run jet with a screw adjustment. The run jet is the one that I am adjusting from the cockpit mixture control knob. This set up works fine for me. I figure: It ain't broke, so I don't need to fix it. In my company of one, I am putting the design engineer on furlough and turning the flight testing over to the test pilot and flight test engineer.
Sid Wood smwood at md.metrocast.net Tri-gear KR-2 N6242 Mechanicsville, MD, USA ------------------------------------------------------------------ > Sid, does your engine go very rich at mid to low throttle settings? > Mine with the Zenith carb was good at idle and full throttle, but went > very rich to the point of fouling plugs at mid range. I didn't know > what was going on until I installed the mixture meter then I could > compensate for it. Spoke to an engineer at Zenith and he told me that > the part number for that carb was the generic one not tuned for a > particular engine and there was a jet in it that should be a little > bigger to even out the mixture across the whole throttle band. > > Brian Kraut > > -------- Original Message -------- > > > Made the first ground engine run after: the engine re-location (to > adjust > CG), installing new RevMaster oil cooler, oil pump (to control high oil > temps), moving the fuel pump (to fix vapor lock) and adjusting the > Zenith > carb. After an eight-month stand-down the 2180 VW fired off on the > fourth > blade; runs smooth and strong. After a little warm up idle can be set at > > 600 RPM, but shakes a lot. 700 RPM is much smoother. OAT was 57 F & RH > about 95%. Carb was making ice at 28 F. Carb heat works well. Cabin heat > > off the oil cooler works good. Mixture Meter works good. Have 6.9 hours > TT > on the engine. > And no leaks!!! > Need to finish the cowl, do another W & B, sign off the condition > inspection > and get on with Phase I flight testing. > > Sid Wood >
