puch problem

I have a 78 maxi last time I rode it (4 days ago) it ran great. Took it out tonite and it ran good for about 2mins started cutting out at full throttle really bad and then just all together died on me. I pedaled it home and later got it running, but anytime I gave it gas it would bog and die again. There is some rust in the tank, but the previous owner told me the fuel filter would take care of that? what do you guys think? I plan on kreeming the tank tomorrow and cleaning carb let me know if you have any ideas, thanks - Joe

Re: puch problem

Smitty Smith /

Check for sediment/water in the carb bowl, and give it and the tank a good cleaning. (along with preferably replacing the fuel line and filter)

Re: puch problem

I would use Kreem as a last resort... take Smitty's advice and see if you can avoid putting all that gunk into your tank! A good flushing with muric acid or even the first two Kereem steps and soapy water and you sould be fine.

Re: puch problem

where can I find muric acid?

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any Hardware store...read this..

http://www.mopedrepairmanuals.com/gas.html

I had chunks of rust in my Newport tank.. I cleaned it and I don't even need an in-line filter now! (I know this is heresy around here.. and I'm not recommending it to anyone else but I like the flow without a filter and I check my carb often and havent had a speck of rust in over a year!)

Re: puch problem

where did you find the phosphoric acid? said it might be hard to find.

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they sell it by the gallon at Hardware stores for like 5 bucks

read this article.. scootertherapy in Madison WI is a great place with a great crew of helpful people and the website has lots of practical tips..on dumb but important things like tire changing techniques. exhaust cleaning etc

http://www.scootertherapy.com/acidtankpage.html

Re: puch problem

Phosphoric acid is the main ingredient in almost all the popular rust removers.. Naval Jelly is a gelled phosphoric acid. Various strengths of "Metal Prep" are available at a good automobile paint supply store.. and this may be the cheapest source.

but i never seen it anywhere close to $5 a gallon.. or even $10 a gallon.. its very expensive compared to something like muriatic acid (hydrochloric acid used for swimming pools.. [do NOT use this stuff]).

I agree that not using a filter is a good thing. For me it's just something else that might leak and it's hard to tell if a filter is clogged and resisting flow.

I disagree about the Kreem coating.. Although imo it's overpriced, if applied correctly it provides the fuel system with very long term rust protection.. long term meaning many years.

Simply de-rusting a rusty tank will last for quite a while but unless the rusty surface was sandblasted, cleaned and sealed, eventually more rust will develop, flake off and get into the fuel.

Re: puch problem

Smitty Smith /

Gas cans, gas pumps, and even the tanker trucks that deliver the gasoline to the gas stations, are all subject to having "trash" in them, which ultimately get transfered into your moped's fuel tank, and the inside walls of rubber fuel lines can flake off into the fuel stream. Even the change of outside temperture makes metal fuel tanks "sweat" (condensate) inside, and even the tiniest of moisture can cause rust-spots to form inside the metal fuel tank, which usually end-up contaminating the fuel system. To me a fuel filter is a very smart idea because of the above described conditions. Some people may get lucky enough that they've not had any problems with fuel contamination, but I'd rather "be safe than sorry". If installed correctly, fuel filters will not be anymore likely to leak than the fuel line connections to the tank and carb.

Re: puch problem

I didn't mean to say to never use Kreem (the third step with the plastic goop)... I was just voicing my opnion that it should only be used in extreme cases and not as a matter of course for a slightly rusted tank. I'm sure it is fine if you are like many of the experienced restorers on here but for a newbie to slosh this around in the tank and correctly pour off the excess is no easy task... especially in a step through where the tank cannot be removed and you need to pick the ped up and turn it upside down and all around to coat everything. It can quickly turn into a huge mess and leave you with chunks of the stuff floating around and clogging everything from your gas cap vent to your fuel petcock.

I found that once the rust is removed the oil in the pre-mix will coat the interior of the tank nicely and prevent further rusting... and it's always good practice to keep the tank topped off with premix to prevent air and moisture from coming in contact with the metal in the tank interior...

Thanks joew for confrming my thoughts on the in-line filter.

These peds were well designed with filters built into the petcock (my magnm has 2.. on on the inside of the tank and a cleanable nipple style one that is inside the exterior connection on the outside of the petcock... as well as the removeable screen in the banjo bolt. So thats 3 filters in the line already. Plus on the stepthrough models the petcock is practically paralell to the carb and there is only about 1 1/2" of line to try to squeeze in an inline filter and it basically forces the fuel to flow sideways and not downward... also, the design of the carb is such that if any debris somehow does get in it sinks to the bottom of the bowl and sits there.

Since about 99% of the problems people post to the repair forum usually involve obstructed fuel flow to the carb I have to believe that as often as not the improper flow to the carb its caused by all these filters as much as anything else!

just my two cents lol :P

Re: puch problem

how do I get the cable disconnected from the top of the carb?

Re: puch problem

loosen the carb at the manifold and swing it forward towards you a bit... you dont have to remove the carb...

loosen the two screws on the top enough to lift off the top... the cylinder will come out along with the choke slide which will fall into your hand..hold the top with the cable in one hand and push down on the cylinder compressing the spring.. the end of the cable will pop out of it's hole on the bottom of the cylinder... push it over to the other hole which is larger and it will pop out... just reverse the process to reinstall the carb!

Re: puch problem

I've got the carb out. I think I might have screwed up the throttle cable so looks like im going to need a new cable. How do I get the float disconnected? I think that and a few small rubber pieces and I will be able to let it soak in some carb cleaner tonight. also I have a 64cc polini kit 15mm carb high flow air filter and bi turbo, the jet says 92, isnt this to big? I took the plug out and it was black, although the engine was cool. it wont run so I cant do a real plug chop right now

Re: puch problem

ok all I need to get out is the float and there is a black plastic cap that you press down that I cant get off any tips?

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if you want to get at the float.(and I'm assuming its a Bing carb if it's on a Puch) then you have to remove the carb and unscrew the float bowl from the bottom.. make sure you have a fresh gasket handy... you may not need it but if the old one disintegrates when you unscrew the bowl you will have to replace it or it will drip!

Re: puch problem

my carb actually looks really clean. what else could suddenly make a engine cut out and die? ran good for about 15mins this morning and now it wont start

Re: puch problem

spray some Starter Fluid into the carb's intake or remove the plug and spray a little in there.. replace the spark plug with a new one... attempt to start it.

if it fires up for a couple seconds, something's wrong with fuel delivery but ignition is ok.

If it doesnt start (you already have a new plug) check for spark.

Remove the (new!) plug, attach the plug to the boot wire and firmly ground the plug's metal base to a clean spot on engine block's fins with a clamp or something. Kick the engine over.

Look for bright blue sparks on the tip of the plug. If there's no spark you have an ignition problem. Perhaps the kill switch or ignition switch has problems.. a loose connection someplace..

(Don't go nuts testing or replacing components in the search for an ignition problem. It's most likely a very simple thing. Sudden, serious ignition trouble due to failed components is rare.. except the spark plug, which do seem to go "bad" all of a sudden.)

"wrong with fuel delivery" could mean anything.. maybe the fuel mixture is so rich it's fouling the plug...(IS the plug wet?) or there's no fuel in the tank... or the carb's dirty and no fuel is actually getting through it and into the engine..

Re: puch problem

ok im going to go buy a new plug. It has an autolite in it now I would like to either get a bosch or ngk anyone have a part # for me?? thanks

Re: puch problem

the guy behind the counter has conversion charts with numbers.. call first to be sure he's got one in stock.

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thanks a lot I called auto zone they have then in stock, thanks

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ok cleaned the carb replaced fuel line and fuel filter replaced spark plug, still wont run! checked for spark at first I thought there was NO spark. I checked it again in complete darkness and there is a VERY VERY small amount of spark. what should I do next? thanks - Joe

Re: puch problem

replace the condensor.The condensor has 2 purposes 1 to allow the quick collapase of the manetic field, therby allowing a build up of currrent in the secondary windings of the coil which will be allowed to the spark plug at the right instant.Also it keeps the points from over spraking at the breaking of the points reducing wear.If the condensor has failed it will either not work at all or very reduced spark will occur.

Re: puch problem

make sure _all_ ignition related wires and connectors are well connected.. tight and no corrosion. Make sure the boot fits tight on the plug. Make sure the ignition coil is well grounded.

.. and then double check for spark. The plug's metal base has to be very well grounded to a clean spot on the engine..

You got spark but its a weak spark. The magneto is generating energy. Energy is leaking away somehow..

This bike " ran good for about 15mins this morning and now it wont start " ..

So, i dont suspect some component (like a condenser) had any reason to suddenly fail. I don't think cleaning points would fix it. Whatever happened happened suddenly.

It's far more likely that something vibrated loose.. and maybe something was improperly re-connected or twisted and broken while searching for the trouble.

Keep messing with the wiring .. the fact that you do have some spark means you're almost there.

Re: puch problem

yeah.. thats the first thing i thought of too.. i just dunno..

for some reason i get this mental picture of a bike with electrical tape holding everything together.. kinda like one of my bikes :)

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I've only had the ped for a few weeks the kill switch was broken when I got it, but it was stuck in the "run" position so i've just been pulling the plug wire off to kill the engine maybe something is up with that switch I guess I will have to go thru everything tomorrow. I hate wiring and suck at electrical issues!

Re: puch problem

ya hate electrical? well, join the club.. its a big club.

Re: puch problem

lol glad to hear im not alone

Re: puch problem

LOL.Jim

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when i replace all my wiring after rebuilding the engine. about a week later i noticed the ped would kick out occasionaly i thought it was the kill switch at first, but discovered that one of the wires coming from the magneto to the wiring block was lose and when i went over a bump it died until it would not run at all. It took me a while to find it this spring check all the screws on the wiring block for tightness.Jim

Re: puch problem

My switch was brocken like that last year the plastic piece that you push back and forth snapped off. The switch will still work just use a sharp point ie:"screw driver ect."to move the switch to the position you want run or kill.

I replaced my switch with a metal toggle switch I bought at radioshack it mounts inside the original switch housing and looks almost stock and will never where out or break again.Jim

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