my moped still wont run

Morgan Walsh /

i have a 1977 puch maxi that ran for a while then stopped.......i cleaned out the gas tank i cleaned out the carb what else can i do????????? oh and let me tell you what it does it wont turn over it wants to but cant and right when i give it gas guess what it just dies i dont know maybe i should pay someone to do it but i wanted to learn how oh well

Re: my moped still wont run

couldbe your spark plug.

Re: my moped still wont run

Andy Kochvar /

How old is the gas? Correct mixture? any leaks of oil? when you start it, can you hear air nosies around the cylinders?

Re: my moped still wont run

(Trying a brand new spark plug, like Zach said, is always a good idea.. amazing how many times this works..)

But since it stopped running for no apparent reason, i think you were on the right track.. something about the fuel flow failed. About 95% of starting and running problems are fuel-delivery related.

If i had to guess, i'd say a piece of junk got into the main jet and is partially blocking it. (The main jet is a tiny little hole inside the carburetors float bowl that meters fuel.)

Now, when you open the throttle, a whole lot of air gets in but almost no gasoline is mixed with that air, so the engine dies.

Although you cleaned the carb, do it again. This time do it more carefully. Use good lighting and use compressed air to blow out all the little holes and passages. Be extra careful and take your time.

At best the bike will suddenly run fine. At worst you will have certainly eliminated one possible cause for the problem.

Re: my moped still wont run

when ever a ped doesn't run, check for spark If you do not know how to, then read freds guide. Then read freds guide again. Then tell everybody else to read freds guide. (it is in the articles section)

Re: my moped still wont run

Don Pflueger /

you have an air leak somewhere. tighten the intake bolts, torque the head bolts to 10 ft/lbs, and clean out the exhaust. also make sure the air box is mounted tight.

Re: my moped still wont run

What? Why do you think he has an air leak. I bet his points are dirty, his plug is fouled, or his carb is still dirty.

Check for spark, then check to see if gas is getting the to plug. It will be wet after trying to start it.

The things DonP mentioned are also likely possible actions to take, but all of them usually exhibit other symptoms than not running.

Re: my moped still wont run

Don Pflueger /

because of the symptoms he explained.

Re: my moped still wont run

Sean Reisdorf /


Did you get your ped running yet?

While all the advice you received is good, lets first diagnose the concern before throwing parts at it and/or tearing the bike apart.

The easist way I know to identify a possible carb/fuel concern is by doing the following.

You need a can of eather, also know as starting fluid, but carb or brake cleaner in an spray can will do.

You stated that the bike starts, thats good.

Now, and this is tricky, just before the bike feels like it is going to die, or at the same time when you hit the accelerator, spray the "fuel source" into the carb.

It is a good idea to have the air box removed for this test.

If you can only keep the ped running by spraying the carb then the concern lies in fuel delivery!!!

This could be caused by a few things...

1.) mis-adjusted float

you have enough fuel to start the ped, but not enough to keep it running

2.) plugged meeting jet.

3.) restricted fuel flow. This could be from a plugged fuel valve, the one actually in the tank.

If you CANNOT keep the bike running by spraying into the carb, try spraying around the carb and intake.

Someone mentioned an air leak.

If you have an "air leak" you'll know where the leak is located because you'll be able to keep the ped running by spraying that area.

If you still cannot keep the ped running, then your next likley cause will be spark. This could be at the end, via the plug, at the beginning, points, or somewhere in between, coil or plug wire.

Hope this helps!


Re: my moped still wont run

If you try a new plug and you still dont get any spark then try cleaning out the magneto because there might be some rust built up in there. If you're getting spark and the thing still wont start then i would do what donp said. Tighten the intake screws, manifold screws, and also check the manifold gasket.

Good Luck

Re: my moped still wont run

Don Pflueger /

from what i read and understand, he says it starts and runs, but when he gives it gas it dies. so that tells me he has spark, but when he opens up the throttle, it gets way too much air and thats why it dies.

Re: my moped still wont run

Steamboat Aka J. R. Stevens / check out MA's own diagnostician.FRED

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