Moped no longer starting

I had my Magnum running, although rough as it had a few air leaks at both ends of the intake. I put some O-rings over top where the intake goes into the carb and that fixed that leak (it was running smoother). I then changed the intake gasket (for a second time, as that gasket was fairly new) and now moped will not start at all. Today I put in a new spark plug just to be sure, and I've re-seated the intake gasket a few times as well. I pulled out the main jet, blew some carb cleaner into the needle jet as well as cleaned the float bowl. Float pin is new and float seems to be working fine.

I don't have a compression tester but when I pull the plug, put my hand there and give the pedals a crank, I am feeling pressure.

Points have been cleaned but I haven't set the timing.

What should I be looking at next? It's driving me a bit crazy that I finally got it running and am now back to square one..

Thanks

Re: Moped no longer starting

sorry, should have mentioned, there is a new petcock and fuel filter on there and when I pull fuel line off and open petcock, fuel is flowing..

Re: Moped no longer starting

Probably Fred /

Check for spark and if you have spark Put a half a soda straw on gas in cylinder plug hole and see if it fires.

Re: Moped no longer starting

Sorry Ken, can you describe this a bit more? Not sure what you mean. Thanks.

Re: Moped no longer starting

Probably Fred /

Gary Imh Wrote:

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> Sorry Ken, can you describe this a bit more? Not

> sure what you mean. Thanks.

Put a little gas in plug hole as to prime it, pedal the crap out of it and see if it fires if it starts but then still dies you have a air leak fuel problem bad seals,

blah blah blah.

Make sure choke slide is clipped into actuator correctly, use choke when cold starting

Re: Moped no longer starting

OK, finally got some time to give this a go. Put some gas in plug hole and it did start for a second and then quickly died. Now I notice that there is some oil dripping out of my exhaust at the red arrow in below picture.

Could this be related to my starting problem? If so, is it just a matter of changing that rubber ring on the exhaust pipe or should there not be oil like that in my exhaust?

Thanks

Re: Moped no longer starting

Probably Fred /

Not related, It will start with no exhaust let alone a leak and that's not the original exhaust coupling either there is no rubber ring

Re: Moped no longer starting

So how do I now proceed to find the starting problem? You mentioned air leak before but not sure how to look for one if I can not even start it.

I recently flushed tank with vinegar, etc. and installed new petcock. If there was some residual water in tank when I refilled it with gas, could that cause the problem? (edited)

Re: Moped no longer starting

Use sealant on your intake. Overseal things if you need to.

Re: Moped no longer starting

Jesus G. saldivar /

I recently had the same problem with my mk 2. I cleaned the carb and it did not work. Took out the carb several times and the floater was set incorrectly. I struggled a bit to make it work but now it was spilling gas everywhere. I did not noticed until like two miles of driving it. So the next day , it wont start again, I was about to remove the carb when I saw there was no gas flowing in the tube out of the gas tank. I had spilled all the gas. So I again went through the whole cleaning procedure but this time I saw on you tube the video from Travis on how to clean a puch carb and how to set the floater parallel to the carb upside down. I finally got it and has been driven since then. You are not getting any fuel in there.

Re: Moped no longer starting

♣Slew Foot♣ /

if the exhaust is clogged it won't start.

Re: Moped no longer starting

Thanks all. This weekend, I emptied the tank and refilled with fresh gas and also temporarily removed the fuel filter just to see if it could be a fuel supply problem. I also put some sealant on the intake manifold because there was an air leak there before. I had to pedal the hell out of it but it eventually started. I then sprayed some carb cleaner on the intake and the bike quickly died. Now it's not starting again.

I've ordered another new intake gasket and will put extra sealant on it. Have also ordered new clear fuel lines (I had replaced them with black rubber ones but want to be able to see the gas flowing) and a new fuel filter.

I had previously checked the float and it looked fine as per Travis video. Will check it again. And will also look for clogs in exhaust.

Finally got it titled and registered today as well so hoping to ride it soon.

Thanks (edited)

Re: Moped no longer starting

Funny shit, I'd think it would be hilarious if this entire time your fuel filter was installed backwards.

Re: Moped no longer starting

I thought of that. Made sure it was correct but tried it both ways just to be absolutely sure!

Re: Moped no longer starting

I finally got this running. Had a bad air leak at intake and have fixed that with sealant. Also found some rust in fuel filter so drained tank and put in fresh mix. Starts right up now and idles fine but when I give it more than half the throttle, it dies out. What should I be looking at to fix that?

And apologies if this is a stupid question but if I have the bike idling on its stand and I'm not giving it any throttle at all, is the back wheel supposed to be spinning at all? Mine does and I'm wondering if that means my throttle cable is not set properly?

Thanks.

Re: Moped no longer starting

Jack Rutherford /

If after you've completely warmed it up the rear wheel spins at more than a snail's pace, you generally just adjust the throttle stop screw and idle screw on your carb. A little movement is generally fine in my book. Normally, just un-richen throttle stop screw by turning to the left a tad bit 1/8-1/4 turn. Throttle stop screw is one usually directly underneath the slide but am not familiar with your carb.

Re: Moped no longer starting

Check for fuel flow if you saw rust on the filter(replace it BTW?). The petcock has a screen,so it's probably plugged with that rust too. don-ohio (:^)

Re: Moped no longer starting

Thanks for reply. I did replace the fuel filter and had changed petcock when I originally de-rusted the tank. Will check that screen though.

Re: Moped no longer starting

It could still be an airleak. Did you dampen the new intake gasket with oil? It won't work dry. Now that it's idling you should do a spray test with carb cleaner to test for leaks.

Re: Moped no longer starting

I could not find a gasket that fits properly. Maybe my intake is not stock as I went through most of the gaskets available on Treats and the holes for the screws do not line up. I ended up with a makeshift one that I cut but put a lot of sealant not only on the joining pieces but also on the outside of intake where the seal is. Looks like shit but I've thoroughly sprayed it with carb cleaner and there doesn't seem to be any leak at all. But no, I didn't dampen anything with oil.

Re: Moped no longer starting

Take a picture of the intake. It sounds like the intake is a consistent problem so I'm guessing that the problem is still centered there. Make sure you're using real gasket paper and put the intake header against a piece of glass to make sure it's actually flat (who knows). Finger testing for compression only proves that you have some or none but I don't think that anyone can accurately feel the difference between 80 and 120psi.

I don't think fuel flow is the problem. If you had no flow at all it would be obvious as the bowl would be empty and slow flow wouldn't prevent it from just starting since the bowl would fill while resting.

Re: Moped no longer starting

Thanks. I will look into the intake again. However, I did rev the engine high last night and sprayed carb cleaner all over the intake and there was no change so I'd be surprised if there was a leak there. I did notice yesterday that if the bike is on its stand with wheel off ground, I can give it plenty of throttle and it's fine. But when I actually get on it with the wheels on the road and give it a throttle, it loses power when I give it more than a bit of gas.

I'm beginning to think I may not have gotten all the rust out of the tank and make give that another go. I did it with the tank still on the bike last time but will see if I can figure out how to take the tank off this time.

Apart from air leak or fuel flow, could it be anything else? I'm very new to mopeds and haven't tackled adjustment of timing yet. Could that have something to do with it?

Thanks again.

Re: Moped no longer starting

Gary Imh Wrote:

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> But when

> I actually get on it with the wheels on the road

> and give it a throttle, it loses power when I give

> it more than a bit of gas.

This is a classic symptom of compression/lean problems. I would buy or borrow an actual compression tester. Not all compression issues can be tested with carb cleaner, it could be a seal/case gasket or it could be damage to the piston/cylinder from a previous seize. Don't move on from compression. Testing with carb cleaner is useful but far from definitive.

It's also possible that the pipe is blocked. Since it appears that your pipe is already broken in two, it should be an easy check.

If it were a fuel flow problem it would die regardless of load. A stock ped can actually go pretty far on the gas in the float bowl alone. Certainly a couple blocks before dying.

Re: Moped no longer starting

Thanks. Will check pipe first and if no blockage, will move on to compression test.

Re: Moped no longer starting

Took off exhaust pipe and don't see any clogs in smaller thin pipe. However, the large one has what I suspect is a baffle or something in it and the end piece that I believe is supposed to unscrew is not moving (I guess thirty years of heat will do that). Is this piece the muffler and how do I check it for clogs in it? Is that piece inside supposed to come out?

Thanks.

Re: Moped no longer starting

I picked up a compression tester today and looks like mine is coming in around 115psi.

From what I've read, 120 for a Puch E50 is minimum so I'm coming up a bit short. But would being just a bit off be the cause of my problem i.e. losing power drastically when I give it some throttle under load (revs up fine when no one is sitting on it!).

Not feeling very confident about pulling engine off and opening it up so want to exhaust my options before I go there! For what it's worth, compression test was done with exhaust pipe on (no clogs) but muffler off (still working on that one).

Thanks

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