1980 Puch Maxi - not running (petcock?)

Hi everyone,

I didn't see this in any other thread, but I have a quick question (please refer to attached picture). The left is the old, the right is the new.

What's the top white thing at the end of the new petcock? Is it a filter of some sorts, or should I take it off?

I left it on, but the Puch's not running...

I bought a 1980 Puch Maxi off of someone from Craigslist, and he said all I needed to do was to replace the petcock. He poured some starter fluid into the Carb to demonstrate that the Puch could run (although very briefly).

Should I have taken that white filter/cap thingy off?

Thanks you,



Re: 1980 Puch Maxi - not running (petcock?)

fallout Survivor /

It is a filter. Do not take it off. On the old one it fell off or disintigrated.

after you replace the petcock, and if it does not run you probably need carb work.

Re: 1980 Puch Maxi - not running (petcock?)

Thank you John. I called the guy who I bought it from, and he suggested that I take it off, since the Puch's not running.

I'm beginning to believe him less & less. When you say carb work, do you mean disassembling the carb to clean it?

Re: 1980 Puch Maxi - not running (petcock?)

Road Rash Dave /

Make sure there is gas in the tank...yea i know...

pull the fuel line off at the carb and put it in a can or somthing like a bowl and turn the petcock to on or reserv an make sire fuel flows out

if it doesmake sure the floats arnt stuck in the carb...if you have fuel

check for a good blue spark...if you have both of those you need compession and if you have that it could be a crank seal leak so it wont suck fuel in....so go one step at a time

Re: 1980 Puch Maxi - not running (petcock?)

As said above, what your Puch probably needs is the carb cleaned. If there's so much as a spec of dirt in there it won't start. On the end of the Petcock is a filter, assuming you're new to mopeds the person that you bought it from is most likely telling you anything so that you won't blame it on them. It's also a good idea to make sure that your fuel is flowing, so with the fuel line running into a can, turn on the petcock and make sure fuel comes out before you do anything else. If the moped is stock than the carb is probably a bing, they're extremely easy to assemble/disassemble and there's practically nothing to them. If you can get a can of compressed air, that would help, if not, just open it up and see whats inside. If it seems dirty you can use a single wire from a wire brush (etc) and gently try to loosen up and scrape away any visible dirt. Take it apart completely and run the wire through every hole, making sure it comes through the other side. Here is an extremely helpful video showing how to take apart/put back together/ clean a bing carb. (http://www.youtube.com/watch?v=9_iaVS5L-jc)

Best of luck!

Re: 1980 Puch Maxi - not running (petcock?)

On a moped, gas starts in the tank, goes through the petcock, through the fuel line, into the carb through the fuel fitting (banjo), into the float bowl, out of the float bowl through the jet, then into your engine. If any one of those things is blocked, broken, or not working properly, your moped will not work because no gas will be getting to the engine.

If the guy said you needed a new petcock, you should probably just get one. They aren't all that expensive, they're pretty easy to put on, and the old ones seem prone to leaking/being clogged. Start with a new one, and that's one thing to scratch off your list. (This is also a good opportunity to clean your gas tank, if it's dirty. See here).

Anyway. Turn your petcock on. If fuel flows out of it in a pretty decent stream, move on to the next thing -- fuel line and fuel filter. Usually it's pretty apparent if these need to be replaced. If you don't have an in-line fuel filter, get one.

If you have fuel flow into the carb but no fuel flow to the engine, your carb is dirty. Clean it.

You'll know you're getting fuel to the engine if trying to start the moped makes the spark plug wet with gasoline (if you're testing this, try to start it a handful of times before checking the spark plug. If it's dry, try choking it, then check the spark plug.) If the spark plug is dry, then one part of your fuel system is still clogged or otherwise broken/malfunctioning. If the spark plug is wet and it still won't start, check for spark. Also read Fred's Guide.

Re: Carb cleaning?

Hi everyone, thank you so much for you all your help! As recommended, I've checked the petcock, which seems to be fine.

I tried cleaning the carb, but can't seem to detach the fuel valve. I noticed that there's a small pin, which I can poke to remove it. Should I remove it? (I've attached 3 pictures). I'm afraid after I poke it out, I won't be able to put it back in.

After doing some research, it seems like this Carb's not a normal Bing one. It seems like this Puch was modded with an Athena kit.


Any suggestions on how to disconnect the fuel valve to the Carb?

I appreciate all the help so far.

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2012-06-30 15.40.04.jpg

Re: 1980 Puch Maxi - not running (petcock?)

if you're talkin about the throttle cable...you push down on it and over to release it from the carb slide...looks like you're missing the float too...unless you took it off...i'd "dip" that carb...it's a mess...

Re: 1980 Puch Maxi - not running (petcock?)

Ah, so that's how. I did take off the float, and will dip that carb in (carb cleaner?). Thanks matt!

Re: 1980 Puch Maxi - not running (petcock?)

you can use this but it's kinda pricey...


personally, i use the spray can

Re: 1980 Puch Maxi - not running (petcock?)

Get a gallon, disassemble, and drop it in there for a couple days...you will be amazed when it comes out!!!

Re: 1980 Puch Maxi - not running (petcock?)

if you do so...make sure there is no rubber or plastic on the carb...it will go away if there is...

Re: 1980 Puch Maxi - not running (petcock?)

Cool! Thanks everyone :)

Re: 1980 Puch Maxi - not running (petcock?)

Jimmy Benedetto /

I have some what the same problem.....

1976 Puch Max 2 1.5 hp

Has sat for over 30 years, cleaned tank carbie and petcock valve. Bike runs good.

Only issue i found is the filtertube from the petcock valve into the tank is broken inside the tank. So the fuel going thru the petcock valve is. Now a bit restricted

(from old tube i think ) and the fuel is now unfilterd as well..

My question is when i install the new. Petcock will i have enough clearance to poke the tube with the filter into the tank or do i have to poke the hole bigger with a drill or poker to clear the way for the new filter on the petcaoc ?? Thanks

Ps first post thanks for having me...

Re: 1980 Puch Maxi - not running (petcock?)

By the looks of it , you'll want to pull the old out .

Re: 1980 Puch Maxi - not running (petcock?)

first rule of mopeds, drill to fit as necessary. second rule don't force especially when inner voice tells u too.

Re: 1980 Puch Maxi - not running (petcock?)

Jimmy Benedetto /

Installed replacement Petcock today worked ok easy installation

I tried pulling the old broken petcock out with needle nose got most of it out but filter bits fell into tank, did a clean tank prceedure and tried blowing and vacum out but with no luck. Will have to live with it i guess. Will see what happens, bike running fine with clean filterd fuel.

The new petcock is not labeled i/e off main reserve so will have to label on the bike later to avoid confusion, and also had to modify plastic chain cover as new petcock lever is bigger than the original part

Overall easy fix and Amazon to the Rescue again for less than twenty bucks


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