Mikuni vm carb

[KRAZYMATT]

Put mikuni vm32 carb on my vrx460 and installed in club car carryall and used factory club car fuel pump. It appears pressure is too much for the needle to stop the flow of fuel because whenever it’s running there is a constant stream of fuel dumping out of the overflow fitting. I know a lot of people that have issues similar to this install a return line before the carb back to the tank. My question is can I just run that overflow back to tank or should I put in return before the carb? Does anyone use pressure regulator? Any input on things to check or try ? I have not opened it up. I should have time to mess with it Friday and will see where the float level is set also. May need tweaking. Didn’t know if the club car fuel pump (low pressure) would still be too much for the vm carb as I think most applications for this carb are gravity fed tanks...

[Low-Tec]

You should be able to get a needle and seat for the VM that is compatible with the pump.
The easiest solution is a return line.
Anything else is just over complicating things.

[KRAZYMATT]

Originally Posted by Low-Tec

You should be able to get a needle and seat for the VM that is compatible with the pump.
The easiest solution is a return line.
Anything else is just over complicating things.

Is it a whole different needle and seat or can it be achieved just by adjusting float height?

[raydhd]

The VM's on sled engines like Suzi's all use pumps. So it certainly can be done. I don't know if this help but for the VM 34 on the sled engine they call for a float arm height of 22-24 mm. I don't see anything else listed in the manual that is special.

[slonomo]

Is it an optical illusion or are those fuel hoses SUPER HUGE?

[slonomo]

Assuming your float is set correctly, I vote for the fuel return line. I installed mine just in front of the carb, and I used the next size smaller fuel line. I used a simple brass tee fitting found at your local NAPA. I think the stock fuel line is 1/4" right? So 3/16" for the return line. I also ran a steel fuel line and threaded it into the top of the plastic fuel tank with some thread sealant. Worked great, no more flooding.

[KRAZYMATT]

Originally Posted by slonomo

Is it an optical illusion or are those fuel hoses SUPER HUGE?

All normal size 1/4” there is 1 short section of 5/16 just before the carb because the inlet on the carb is 5/16”. The barbs on the fuel filters I use have 1/4” and 5/16” on same filter so I brought 1/4” all way into filter from tank then converted to 5/16 out of the filter to the carb.

[KRAZYMATT]

Originally Posted by raydhd

The VM's on sled engines like Suzi's all use pumps. So it certainly can be done. I don't know if this help but for the VM 34 on the sled engine they call for a float arm height of 22-24 mm. I don't see anything else listed in the manual that is special.

Thank you.

Originally Posted by slonomo

Assuming your float is set correctly, I vote for the fuel return line. I installed mine just in front of the carb, and I used the next size smaller fuel line. I used a simple brass tee fitting found at your local NAPA. I think the stock fuel line is 1/4" right? So 3/16" for the return line. I also ran a steel fuel line and threaded it into the top of the plastic fuel tank with some thread sealant. Worked great, no more flooding.

I have not tinkered with it at all. Just put it on as it came right out of the box. I’d like to get it dialed good without the extra return- which sounds like it’s doable. I haven’t ran it but maybe 2 minutes total- I am still working on exhaust for it so as it sits right now it shoots flame out the exhaust port right at the plastic fuel tank so not running it yet! I just bumped the key as soon as the carb had fuel it fired right up!

[raydhd]

Another note I am using the Holley Mighty Mite electric fuel pump that is listed @ 1.5 - 4 PSI so the carb is under constant and steady pressure. I am routinely @ 5500 rpms so it certainly keeps up the flow. When I put the VM 38 on my HD ironhead which is gravity fed it poured fuel out of the overflows out of the box and the float height had to be adjusted.

[Low-Tec]

Originally Posted by KRAZYMATT

Is it a whole different needle and seat or can it be achieved just by adjusting float height?

http://https://www.denniskirk.com/mi...prd/170459.sku

These are generally available in 1.5, 2.0, and 2.5 gallon per hour.
Remove your seat from the carb and look at the back end, it's probably stamped 2.5. Snowmobiles generally use the 1.5, the lower flow prevents the the needle from being forced off the seat by the pressurized fuel.
Makes any solution costing more than $18 seem pretty silly.