Mobylette 50v shutting off cliché

Hello!

I recently picked up a great 1978 Moby 50v, got all its parts stickers and covers only thing is, it doesn't stay running for long.

Idles or rides fine for awhile then, just dies. It left me stranded in the Philadelphia ghetto the other day haha. I have cleaned the ever loving crap out of the carb, checked for airleaks, installed an external condenser, drained the tank, cleaned the exhaust and, replaced the inline filter to no avail.

The local moped shop tells me getting rid of the Gurtner carb will fix the problem. Is there anything I am overlooking? I told them to go ahead and order the part to retrofit on a different carb.

Thanks,

Matt

Re: Mobylette 50v shutting off cliché

not even gonna ask about the "local moped shop"

sounds like they just don't care, or you're not paying them to diagnose anything.

ride it until it stalls, pull the plug wire and check for spark, check with carb cleaner to see if it's spark or fuel related.

i'd hate to see you throw money at a problem blindly guessing.

how long is "for awhile"?

something as stupidly simple as a clogged gas cap could be the issue.

and draining the tank isn't cleaning it.

welcome to fantasy island, i mean moped army

Re: Mobylette 50v shutting off cliché

So, I went back and checked for "stupidly simple" and found that it only shuts off when the handlebars are cocked left. So I removed the housing on the top left of the carb and the handle bars turning are affecting the throttle. Cable must be pinched or too tight I'm guessing?

Re: Mobylette 50v shutting off cliché

grats on properly diagnosing it (for a good start)

potentially the cable is acting as the throttle closed limit, rather then the idle adj. screw on the carb.

i searched kill switch on mabecane's forum, 5 pages of results.

as that is rumored to be problematic, Rebel Moby suggests disconnecting it and using the decomp to shut the ped down.

but adjusting the cable sounds like the fix you need.

as for the implied insult of stupidly simple, "it's only mopeds!"

Re: Mobylette 50v shutting off cliché

haha, I didn't take or mean anything as an insult, "it's only mopeds" is exactly what went through my head when I read it. Thanks for a few ideas.

I got that problem sorted out, the handle bars no longer affect the throttle.

I can start it and it will idle(only at a high idle) for 10 minutes or so then shut off and becomes difficult to start again. Or, I can start it and run halfway around a city block and when I stop, it slowly dies and becomes difficult to start. If I throttle it on the kickstand and run it at a high rpm for 5 to 10 minutes, it will eventually just shut off and become difficult to start.

If it has been sitting, it starts up with no problems. The spark is good. Just in case I have replaced the condenser (it was only 4 bucks at an auto parts store so I figured what the heck) and the plug.

Any feedback is appreciated.

Thanks,

Matt

Re: Mobylette 50v shutting off cliché

from Rebel Moby:

http://mabecanemobylette.freeforums.org/post13642.html

Two places where Mobys usually fail by heat fatigue: the condenser, which should be replaced with an external one when you have any spark issues, and the antiparasite spark plug cap, as the resistor inside can become intermittent over time.

also:

Also if the 'ground' wire is in its original location you would want to change that to a wire going from a intake stud to one of the external coil stud as you bonding strap. The original location has proven to be sketchy at best.

definitely tons of good leads in that link.

Re: Mobylette 50v shutting off cliché

Thanks again, that sounds promising, I'll try the plug wire tomorrow!

Re: Mobylette 50v shutting off cliché

So, after reading through the link that was posted, and clicking on more links within those links, that Rebel Moby guy has some good info. The service manual I have says to set the spark plug gaps much wider than he recommended. That and using the plugs he recommended allowed me to tweak and adjust to the point it runs great. Just rode all over the city of Philly, no shut offs! Thanks Mr. Kuehn for your advice and direction. Anyone else with this problem with a 78 Moby, set your gap between .015 and 019 before going n

uts

Re: Mobylette 50v shutting off cliché

Brent Bublitz /

Rebel Moby is indeed a fountain of Moby knowledge. +1

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