Mikuni VM22 on built Predator Hemi

#41
The carb is new. Enrichment plunger is down. I just want to have gaskets on hand if needed. That kit seems to include a bowl gasket (seal) and a needle, spring, and perhaps a seat? I'm actually not surprised. There's a reason why these carbs are popular...not a lot of soft parts. My bowl gasket is good and I can't imagine that <5 hours of run time has killed the needle and seat. I will just disassemble it and give it a thorough inspection and cleaning. Again, thanks Ole. You're the man.

-Ray
 
#42
Is manifold mating surface matching the carb so o ring contacts it all around? IF so I doubt it would leak there. Below the oring on the bottom is a small hole for the idle air bleed adjustment, is it open to the air when carb is mounted to manifold? Only other thing is the float tang adjustment. When holding carb upside down the float seam should be horizontally level.
 
#44
I finally figured this out! Turns out I had to pull the carb off and tear it down to see how it works. As I'm taking the enrichment device apart I realize what Ole told me on January 7th. "Make sure the plunger is down". I was running it with the enrichment device on! Stupid...stupid...stupid. I really need to look at these things with my good eye. Pushing the enrichment lever down pushes the plunger down and turns off the enrichment. I put the 15 pilot back in and tuned the air bleed and now the slide height/idle screw actually does something and has to be turned in a bit. Took it for a ride and it seems to run well with no hesitations. I will start plug reading again and see where the A/F ratio is and adjust from there. Thanks again to everyone who provided advice. You guys are the best!

-Ray
 
#45
Ray, thanks for posting up the results. You made a very common error on the enrichment lever. No big deal, and now you are completely savvy with this carburetor, and will be able to quickly tune in the future. I love these carbs, and I know you will too.
 
#46
Dave,

You are quite welcome. I'm am certainly not afraid of admitting my mistakes and I hope this thread benefits others that head down this path. If you can't learn from your mistakes then you are doomed to repeat them. When I first took this carb out of the box and had a look at it I made the assumption that the enrichment lever had it's fulcrum point between the lever and the enrichment plunger. That was my fatal mistake. I should have had a closer look. Upon disassemble I realized that the plunger was in between the lever and the fulcrum. This of course reverses how it operates.

Anyway, I wanted to elaborate upon what I found when I tore the carb apart. I heard varying accounts of supposed poor quality on these Chikuni's. The outside is beautiful. Looks to be a nice precision casting. Machine work appears to be nearly perfect. The fasteners are not soft and the overall feel is of a quality product. The inside is just as nice. I spent time blowing out all of the passages with compressed air for no apparent reason...no dirt or metal shavings came out during this process. The design could be fubar but I suspect that is not the case since this is an actual Mikuni design. You are correct, I already do love this design. Multiple throttle position based fuel enrichment schemes throughout the throttle range that overlap each other. Brilliant! And all of this without the need for an accelerator pump squirter of any kind! (My internal Holley 4150 guy pokes his head out again).

It is supposed to be warmer this weekend. I can hardly wait to play some more. The spark plug is indicating lean now. I have a larger main jet on hand but will try raising the jet needle first to see what effect that has. Woo! Complex multivariable problems in need of solving. I'm in my element. :p

-Ray
 

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