Carb problem with Mikuni 24

Wiseguy71006

New member
Ive got a 212 and have a brand new Mikuni 24 flat slide and a new Mikuni square body pump. When the engine is running, it pumps fuel past the needle and starts pumping it out of the float bowl overflow hose. I have installed a 2.0 needle and seat in place of the 2.5 that was in the carb. I’ve heard that if you run a pump you need the smaller needle...idk. It still leaks out the overflow tube. I can gravity feed it and bypass the pump and it doesn’t leak a drop of fuel. I even though my pump was putting too much pressure on the neeedle so I bough another new pump, round design this time and it leaks with that one as well. Have any of you run into this, and what did you do to fix this problem? All of my stuff is brand new, not a used piece on the entire engine!
 
Also where are you pulsing from? If it's from the intake it will be stronger than from the valve cover mostly . WOT will decrease manifold pulse somewhat.
 
I have it on the intake, but tried it off the valve cover as well, didn’t change a thing. Thanks for the return tip, although I would hope there is a fix without running a return line. Is that what people do to fix the issue or is it a band aid sort of thing that gets them by? I would think with the small amount of pressure that it wouldn’t blow past the needle and flood the bowl like it does. This can’t be common as I’ve never seen a ”return line” kit for sale.
 
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