If anyone is having issues with the Mikuni VM24SS carb, I thought I would post what issues I had and how I resolved them.
Acquired a 93 Bayou 220 that had sat for over 4 years.
The carb was extremely corroded and pitted and full of leftover fuel.
Cleaned carb and bowl and was able to get the engine to start.
Within 30 seconds exhaust would heat up and start to glow red hot.
Removed carb and recleaned everything, including a second overnight soak.
Needless to say, after removing the carb for the 5th time and my frustration to the limit I
realized that my attention had been to the carb body and not to the bowl.
There is a small brass rod on the bottom of the carb that goes down into the float bowl but is seperated from the main section. I had cleaned that area very well....I had thought.
***The corrosion had sealed off the channel that runs from the main bowl section to the small tube section on the side of the float bowl. No amount of carb cleaner was going to get it to budge. So i took a small nail and started to scrape away the corrosion and was eventually able to dislodge enought of the corrosion that carb cleaner would flow through that channel. ***
I thoroughly cleaned each side of the channel in the float bowl and reinstalled the carb and now the issue of it running lean is gone.
On a second note the fuel mixture screw was a nightmare to remove as the threads had been corroded and wouldnt let the screw come out. I used a little cutting oil and worked the mixture screw in and out until I was able to push past the corroded threads and completely remove the needle. After a couple passes with a tap to clean the threads it is like new again.
Hope this helps if you are having a lean running machine.
