1983 Yamaha 175 Tri Moto Mikuni VM20SS leaking gas ..... need advice please.

[mastiff]

Hello
Im new to the 3 wheeler world and just got a 1983 Yamaha 175 Tri Moto with the OEM Mikuni VM20SS carb. With the motor off and not touching the
throttle cable i have gas pouring out the carburetor as soon as i open the fuel cock. The gas is coming out the overflow brass fitting on the bottom of
the carb and gas must be filling up the float container because its coming out the tiny brass hole in the carb where the jet needle enters. I need help
please. Is it the carb or could it be the fuel pump ?

Thank You.

[muthey]

time to pull and clean the carb very well. Go here to download a manual http://www.oscarmayer.net/atc/manuals/ to help walk you through the carb cleaning.

[eBoyDog]

My YTM200EK with VM22SH carb did the same when I bought it, I went over to bikebandit.com and bought a needle seat set which fixed my carb leak,also would suggest getting a new bowl float gasket while you are at it since you will need to pop the carb apart.

Not familer with your carb but chances are its either the float adjusted wrong or the needle seat bad, download the service manual first as already suggested. I think the needle seat and valve was less than $10 plus shipping but I bought a few other parts at the time so I forget exactly how much. If you create an account on bikebandit and drill downto your model trike, it will show you the oem carb and parts list.

Now with that, I ended up ordering a carb rebuild kit off ebay this week for mine which includes a needle seat set plus more and it was less than $25 shipped, if the carb has needle seat leaking chances are it needs a good cleaning but if its running good perhaps its best not to mess with it as myself a amateur to these Mikuni carbs, they can be really stubborn. If its running good, you may not want to dive too far into it and needle seat set and bowl gasket might be all you need.

[mastiff]

Thank you very much. I will pull the carb apart and see what i have going on in there.

[czac]

could be the float too it could be hung up or need adjusting. its better to just pull the carb get a new float set with the little needle valve and a new bowl gasket and just clean everything really good. I know the manual says not to but, I use a fine strand of wire to clean out all the little holes in the jets... I just pluck a strand of wire bristles off my wire brush I use for welding... it works great. then spray carb cleaner through everything with a hole... lol some of the jets have little rubber O-rings so if you can buy them for your carb, get them and change them out as well.

[Atc70noob]

Also check the drain screw on the bowl,if you have one. Sometimes it loose or the or ring it worn out.