Carb problem, Mobylette?

Kevin Ibbetson /

Finally got a spark from the abandoned '70 Mobylette and got it running, sort of. It fires up and accelerates but won't idle. Just before it's going to die if I close the throttle all the way(choke) and then give it some gas it will pick up speed nicely but then after a few seconds will die again unless I repeat the same procedure. I know what it sounds like and I have 2 carbs to play with and both have been scrupulously cleaned and tried with 2 different jets, a 225 and a 230. The 225 works better. I have checked both the coil and condensor(put a new one in) and filed and gapped the points at various gaps between the recommended allowances. My gas mixture is 25 to 1. There is a newNGK br6hs and have also tried a br5hs. I have de-carboned the exhaust pipe and checked for leaks around the gaskets. I'm getting ready to try a honda carb or just push it off a cliff. Any suggestions? Thanks


Re: Carb problem, Mobylette?

Hami Onder /

I had this problem on my old moby, unfortunately i tried everything and couldn't fix it. Then one day it fixed itself. I dont see how it could be anything other then the carb but for some reason i dont think it was. The only thing i can offer is to mess with the idle screw alot.

Actually now that i think of it, the belt was super loose and that may have been the problem. I think it would loose slack and not keep the variator spinning or something. Someone say if that even makes sense as a possible problem. Check to see if the belt is mad loose.

Also, do a search for my posts and find the one about that problem. There you can read what i tried and what i didnt.

Good luck.

Re: Carb problem, Mobylette?

I have a few late 70's moby 50v's. the gurtner carb on mine have a very tiny, and twisty idle circuit that is very easy to clog. just past the needle jet (towards the intake) is a tiny hole that eventually connects to the higher hole in the bowl.

you should be able to squirt carb cleaner in the higher hole in the bowl, and have it shoot out the top of the carb (with the cap removed) then try to shoot carb cleaner through the tiny hole beside the needle jet. it should also squirt out the top. I have had this problem

you will probably get carb cleaner in your eyes it will hurt

Re: Carb problem, Mobylette?

When I first got my 50vs, I had to give the carbs a good 45 min cleaning. Clean everything with carb cleaner, and make sure every passageway is unclogged!

Re: Carb problem, Mobylette?

Paul Mehalko /

The Moby has a pretty hot spark when it's working correctly.

Mine was pretty lame until I found 2 things wrong. The bonding wire from the engine to the coil on the frame wasn't making a good ground. Get a volt ohm meter out disconnect

the end buy the coil. First check the resistance of the wire.

Shouldn't be more than 1 ohm. If more make a new on or fix what you have. Then measure resistance from bonding wire to the engine - this is where my problem was. All I did is clean the contact between the engine and wire, Scotch brite works great. Resistance there should also be less than 1 ohm.

The next thing I did is clean the points using 600 sand paper. Things been running great since. Also I flushed the tank, soaked and cleaned the carb.

Re: Carb problem, Mobylette?

Kevin Ibbetson /

Thanks for all your advice everbody, i've tried everything I can think of and nothing changes so I'm building a new motor for it! I have the bits so I'll see if that helps. I'll let you know Kevin

Re: Carb problem, Mobylette?

can I get the old engine from you,,

I got a motobecane traveler who needs one,,,

Re: Carb problem, Mobylette?

See Ya Moped Army /

The gas mixture should be 50:1, not 25:1. You're running it to rich with oil.

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