I purchased the RY25AXB because I like the design of the air flow generated cooling the engine and taking the exhaust away. Currently, it is running a little lean as it does not appear to have the torque needed. I do not see a way to adjust the gas mixture and I am relying on the choke to adjust mixture. Is there a way to adjust mixture on this engine?
And be really really careful because the difference between flooding & burning a hole in the piston can be as little as 1/6th of a turn.
I use a colour tune when I adjust the needle on one of these carburettors because they are very sensitive
And be really really careful because the difference between flooding & burning a hole in the piston can be as little as 1/6th of a turn.
I use a colour tune when I adjust the needle on one of these carburettors because they are very sensitive
Some 2-stroke Walbro and Zama carburetors have hidden low and high jets. They apparently don’t want customers monkeying with them. It doesn’t stop everyone and leave it at that.
#5
StarTech
The tamper resistant plugs are there due EPA rules just you will some larger carburetor with mixture screws snapped off after are factory tuned. All you need is the extractor tool to remove these plugs. Zama RB series uses a 2.5mm and a 3mm LH extractors. The 2.5 mm is for carburetor that no one tried digging out the plug and 3 mm is for those that someone tried. Also some of the Walbro rotary valve carburetors the adjustment is actually filled with epoxy after they tune them because so many were screwed with my non professionals.
When these carburetors are improperly tuned a lot of the equipment burn themselves up due to running too lean. Echo especially has tune up chart for adjusting their Zama rotary carburetors (RB series). Stihl intentionally tune their carburetors slightly rich and you tune them to peak performance their coil speed limiters will give you all kinds of problems. Actually we are to using exhaust gas analyzers which is too expensive for most small shops if the EPA had they way fully. But most service manuals will have you tune to peak rpm and drop off by 50-100 rpms by going slightly rich. This means you need and are using a RPM meter.
Even the larger Nikki carburetors used on Kawasaki engine has welch plugs over the adjustment screws to prevent equipment owners from screwing the adjustments. Matter I just recently repaired a Kawasaki Mule UTV where some idiot DIYer screw up the mixture screws so bad that it was impossible to straighten out and I had to put on a $700 carburetor that otherwise would had repairable as it tried drilling out the mixture screws.
