One of the guys was very helpful from GMA he rebuilt the carb for me and when we tuned it. It all seemed good but the next day when I took it to the field and flew it we noticed a lot of sputtering in the mid range. I'm going to reach out to a couple of other fellas at the club and see what they have to say. Most of the guys at GMA wont touch anything but DA. So it's hard to find anyone that wants to mess with this.
I found this guide from a little gas engine shop in indaina or something liket that and they have some good advice:
Let's tune up a Walbro!
Set the lowend & highend needles to about 1 to 1 1/2 turns each. Choke the carb or prime it, until the carb is wet. Fire up the engine and let it warm up. Let's set the topend first since it's the easier of the two. Go to full throttle. Adjust the topend needle for peak RPM. Leave it wide open for about a minute to see if it changes any. Should the engine go lean, open the lowend needle slightly, if this dosen't work... you will have to adjust the needle valve inside the carb.( I will explain this later) If the topend runs OK, then slowly pull the throttle down until the engine begins to "four cycle" hold the throttle there. Adjust the lowend needle until the "four cycling" stops. Now lower the throttle more until it "four cycles" again, and adjust the lowend again. Keep doing this until you reach full idle. Now, from full idle begin to throttle up until the engine starts to bog or hesitate. Open up the topend needle just enough to eliminate the bog or hesitation.
When this is done right, you will be able to set the throttle in any position and it won't four cycle, plus you will be able to transition from idle to full power without any hesitation at all.
1 1/2 turn out on LOW and 1 turn out on HIGH
ORIGINAL: ggroyal1
I switched from Mobil 1 racing 2t motorcycle oil to Redline two stroke racing oil last year and I can tell a difference, all of my gassers run better.
Does your ignition have a timing feature? Mine is set for a pitts type muffler, I have another Evolution that the timing is set for a tuned pipe.
Also, there should be a lot of gasser at GMA that could help. Out of 5 gas ingines, the Evolution 58 has been the hardest to adjust, but it has a lot of power and it was work all the time and effort.
How do you like the Bisson muffler? Any problems with the muffler bolts coming loose?
Thanks,
George