leaking gas issues

ucandoit · Post by **ucandoit** » Wed Sep 24, 2014 2:13 am

First post. First scooter. Pretty concerned. Bought a 2008 buddy 125 with 3100 miles. Seller kept saying he knew nothing about the scooter, except that a new carb. was put in by a friend one year ago. It started easily and ran well. Quickly discovered:
#1 Problem: Gas periodically leaking (a lot) from air filter compartment and from under scooter after turning scooter off. Found gas in oil. Suspect slow leaking, too. Changed oil twice. Cleaned air filter, bought new one.

Never overfilled the tank (1 gal. at most). Problem seems worse with a fuller tank.

I studied a lot: Now, suspect the carb. is flooding & suspect a faulty auto petcock, because of the amt. of gas leaking. I had to siphon the tank just to stop the leaking. However, the motorcycle mechanics keep saying it's probably the float needle. Hmm.

My plan:
#1) I remove carb. and have them check it. 2) I replace the petcock myself.
Is replacing the petcock fairly straight forward? Do I need a manual? Any tricks or special concerns? Am I diagnosing this properly?

Other worry: Could it be a "carb. vacuum hose problem", I read about this.. Should I try to sell the bike to a shop, recoup some money and buy a new one. I like mechanics, understanding how things work, and caring for them, but I need to know my limits. Sorry this post is so long.

PeteH · Post by **PeteH** » Wed Sep 24, 2014 3:56 am

If there's a faulty float needle, there'd have to also be a bad auto-petcock. Even if the float or needle were total carp, it wouldn't make a bit of difference (from a leak perspective) if the petcock weren't still providing fuel.

Now of course that's with the motor off and the petcock ostensibly closed.

However, if the float and needle are ganked, it could pour surplus gas out the carb while the scoot is running and the petcock is open. I don't have a good grasp for the flow rate from the tank, but surely it's more than the scoot uses even at WOT.

The usual way to static-test this is to pull the petcock's vacuum hose off the manifold, then use a syringe or a brake bleeder to pull enough vacuum to open the valve. Then sit back and watch to see if the gas starts oozing out. Do try to carry out this test outdoors, so as not to dump gas in your garage. If indeed it leaks, that does indeed point to a bad float or needle valve, and a rebuild kit is in order.

I haven't pulled apart my Buddy carb. Community: is there an overflow tube from the bowl, or does the gas back up into the manifold and/or air side?

agrogod · Post by **agrogod** » Wed Sep 24, 2014 2:11 pm

Gas in the oil, that sends up a red flag. Could indicate a crack in the block.

ucandoit · Post by **ucandoit** » Wed Sep 24, 2014 4:06 pm

PeteH. Your test of the float and needle basically is allowing gas to flow into the carb. and if it leaks out, then they are faulty. Can I already assume that the petcock is bad because of the amt. of gas that flowed out?

Also, what is a cracked blocked? That sounds bad. If that is the case is the scooter toast & there would be no reason to fix the carb. petcock, etc.?
Thank you.

Benzo Mike · Post by **Benzo Mike** » Wed Sep 24, 2014 4:55 pm

It is not a "cracked block", don't worry about that, please.

You have a faulty petcock AND float needle.

Petcock allows fuel to flow to carb, even with engine off.

Bad/dirty float needle/seat allows float bowl to overfill. The excess fuel runs back up the intake tube AND into the intake port. From there, into the combustion chamber, past the rings, and into the sump.

This is bad for lubrication. It also can demolish your engine. If the crankcase gets full enough, you can hydraulically lock the engine when you hit the starter. Something has to give, usually the conrod.

Common problem on many carbureted motorcycles. Fix or rebuild the petcock, rebuild the carb (at the least, replace the float needle).

ucandoit · Post by **ucandoit** » Wed Sep 24, 2014 9:54 pm

Benzo Mike. I'll take your advice. Today I removed the fuel line from the carb. and removed the vacuum line from the intake manifold, attached a syringe and gently used suction off and on. Off and on. Each time the fuel flowed and stopped appropriately. I was disappointed. The petcock seems to work just fine, though the engine is not running.

I don't want gas in the "sump". Wouldn't I notice that with the oil dipstick, and when draining the oil during a change? What are the symptoms of a damaged conrod? Thank you.

Benzo Mike · Post by **Benzo Mike** » Wed Sep 24, 2014 10:22 pm

Your connecting rod is fine, you would know for sure if you bent it. Gas in the (oil) sump would show up on the dipstick. You're going to be fine. Petcock almost certainly has to be malfunctioning to do what you have described, test or not.

PeteH · Post by **PeteH** » Thu Sep 25, 2014 12:19 pm

ucandoit wrote:Benzo Mike. I'll take your advice. Today I removed the fuel line from the carb. and removed the vacuum line from the intake manifold, attached a syringe and gently used suction off and on. Off and on. Each time the fuel flowed and stopped appropriately. I was disappointed. The petcock seems to work just fine, though the engine is not running.

I don't want gas in the "sump". Wouldn't I notice that with the oil dipstick, and when draining the oil during a change? What are the symptoms of a damaged conrod? Thank you.

Yep. My little test was to see if the petcock itself was working correctly, which it sounds like it is. Unless I miss my guess, the fact that the petcock cycles off when no vacuum is present means that the scoot's fine when the engine is off, and that the problem happens when it actually is running. Therefore the problem _should_ be isolated to the float and needle. So now either the float has a leak, has filled with gas, and is no longer 'floating' and therefore not rising up and shutting off the fuel flow, or the needle valve is clogged/broken. If you drain the carb (screw at bottom), pull the carb and unscrew (gently) the screws holding the bowl on, you'll see the float and valve assembly (as well as the jets) sticking out the bottom. You can sorta test the valve by hooking up a piece of fuel line, blowing gently into the line while moving the float up and down with your fingers. You should feel resistance (complete cutoff) if the valve is working properly. Either way, you might consider disassembling the needle valve and cleaning it with some carb cleaner, or buy a rebuild kit for the carb which should, I think, include a new needle valve and float. Not sure on what's exactly available in rebuild kits, though - I haven't rebuilt since some Honda carbs in the '70s

Let us know what you find.

charlie55 · Post by **charlie55** » Thu Sep 25, 2014 2:03 pm

PeteH wrote:
ucandoit wrote:Benzo Mike. I'll take your advice. Today I removed the fuel line from the carb. and removed the vacuum line from the intake manifold, attached a syringe and gently used suction off and on. Off and on. Each time the fuel flowed and stopped appropriately. I was disappointed. The petcock seems to work just fine, though the engine is not running.

I don't want gas in the "sump". Wouldn't I notice that with the oil dipstick, and when draining the oil during a change? What are the symptoms of a damaged conrod? Thank you.
Yep. My little test was to see if the petcock itself was working correctly, which it sounds like it is. Unless I miss my guess, the fact that the petcock cycles off when no vacuum is present means that the scoot's fine when the engine is off, and that the problem happens when it actually is running. Therefore the problem _should_ be isolated to the float and needle. So now either the float has a leak, has filled with gas, and is no longer 'floating' and therefore not rising up and shutting off the fuel flow, or the needle valve is clogged/broken. If you drain the carb (screw at bottom), pull the carb and unscrew (gently) the screws holding the bowl on, you'll see the float and valve assembly (as well as the jets) sticking out the bottom. You can sorta test the valve by hooking up a piece of fuel line, blowing gently into the line while moving the float up and down with your fingers. You should feel resistance (complete cutoff) if the valve is working properly. Either way, you might consider disassembling the needle valve and cleaning it with some carb cleaner, or buy a rebuild kit for the carb which should, I think, include a new needle valve and float. Not sure on what's exactly available in rebuild kits, though - I haven't rebuilt since some Honda carbs in the '70s Let us know what you find.

I'm curious: is the float level adjustable on the Buddy carbs? I know that it's not adjustable on the Helix's Keihin CVK30's.

ucandoit · Post by **ucandoit** » Fri Sep 26, 2014 1:48 am

PeteH and others: I took the carb. off, (took me days of studying & getting up the nerve) took it to the dealership (they said to bring it in). The parts guy took it apart to show me the float, needle, valve seat, etc., As soon as we removed the bottom float bowl part we saw a good size piece of "crud" (looked like a piece of leaf) in there and he said "there's the problem". We removed both jets, the smaller one (pilot jet) was blocked. He cleaned it. The floats, needle, valve seat were good. It was a nice tutorial, though I would have liked more time to ponder it all. I put it back into the scooter with no problems.

I didn't tell you the dumb thing I did. When someone told me to make sure the drain screw was tight, I got impulsive and turned the air/fuel brass mixture screw, instead. Of course I didn't count the turns. The parts guy said the manual says to start with 2.2 full turns open from seating. Which I did. The scoot starts, but dies at idle speed. It sounds rough. (It ran smoothly when I got it). But now I feel comfortable taking out the carb. and I think I could learn to clean it & get it sound. I need info. on how to tune the mixture screw and get it running smoothly.
I didn't ask if the float level was adjustable. Darn it. I tend to think it is not adjustable. He didn't mention it and he knew the carb was flooding. Also, I don't think there is an over-flow drain. I really enjoy learning. In the end perhaps I'll need to find a way for the mechanic to look at the scooter, but I've learned a lot and it's not so mysterious.
The bike ran better before I changed fuel filters, messed with the mixture screw, etc. I hope I can get it purring. Then I'll move on to deal with other issues. Thank you for all the support.

PeteH · Post by **PeteH** » Fri Sep 26, 2014 2:13 am

Great news - glad you found the blockage.

I think the process now goes like this: Start it up and let it get warmed-up (even if you have to twist the throttle a bit to keep it running). Adjust the idle screw if needed to keep it running. Then adjust the mixture screw to peak RPMs, then drop the idle screw back down to normal. That should get you close, and should still start and idle when cold, assuming the auto-enricher is working OK. See if this works.

ucandoit · Post by **ucandoit** » Fri Sep 26, 2014 4:25 am

PeteH. OK. I know I will have to give it throttle to keep it running. How long does a "warm Up" take, roughly? Would 5 mins. do it? Then I adjust idle screw to keep it running. OK. Then, which way do I turn the mixture screw to begin to find the highest rpm? Also, the spark plug is oily black so it may have been running too rich. I'm just learning all this.

Also, in the back of my mind, I continue to wonder if the petcock is iffy. But, I tend to be pessimistic, so I'll see how things go and concentrate on learning to tune the carb. correctly. I really appreciate your help.

ucandoit · Post by **ucandoit** » Fri Sep 26, 2014 11:02 pm

the scooter starts and idles well. It runs well at taking off slowly, but at about 15 mph during acceleration it skips and misses. At higher speeds it does pretty well.

Have not seen any gas leaks yet. Thank God.

Any thoughts on why it misses on acceleration at around 15-20 mph speed?

Also, before removing the carb. the bike would idle down quickly when I release the throttle. Now, it idle downs more slowly.

Any suggestions? Thank you.

PeteH · Post by **PeteH** » Sun Sep 28, 2014 5:01 pm

50cc experts should now join in, but it sounds a little like a partially blocked slow jet. But I don't know at what point the slow jet transitions to the main.

Perhaps a wee bit of that earlier gunk wound up in a jet? But now that you're good at carb removal it should go much more quickly

ucandoit · Post by **ucandoit** » Sun Sep 28, 2014 10:02 pm

PeteH. I agree about maybe having a partially blocked jet. I may need to go back and take off the carb. and this time take it all apart, studying it more carefully, making sure each jet and all the little holes are patent. The parts guy did most of it and quickly, so I didn't get to know it. Also, he did not remove the top parts of the carb.

Would I need to replace the gasket on the carb. if I take it apart again?

He used brake cleaner to clear the jet. Can you recommend a product to clean the carb.? Can I get compressed air in a can?. I have no air compressor. I know this is a lot of questions.

I love your words about staying CALM and adding SEA FOAM. They give me hope. LOL I'm truly aiming at getting this bike running smoothly and at feeling confident that it is safe and solid. There are no short cuts to this. I have to truly understand the working parts.

ucandoit · Post by **ucandoit** » Sun Sep 28, 2014 10:05 pm

Pete H. My scoot is not a 50 cc. It is a 125 4 cycle Buddy.

PeteH · Post by **PeteH** » Mon Sep 29, 2014 11:39 am

Oh, carp. Sorry. I was thinking of another Buddy-won't-start thread. No big. Same advice: check the jets one more time.

The top half of the carb is where folks sometimes get themselves into trouble. The rubber diaphragm in the upper section can be a little fragile, or can crack/split/rupture if reassembled incorrectly. If your jets are clean, the problem might be 'upstairs', but start with the easy part (the jets). As far as cleaning goes, carb cleaner is good, but can be messy in spray form.

You can clean the jet out with a very fine piece of wire (like a guitar string), but be careful - the jets are made of soft metal (like those bowl screws) and are a precision device. Don't ding 'em up. You might pull them out and soak them in some carb cleaner overnight, just to loosen things up, too. Don't worry too much about compressors and such. Wipe off the outside, then 'put your lips together and blow' (as Lauren Bacall once said).

So to get this straight, it starts and idles, is funky at 15mph or so, but runs better above that speed. Team America: does this sound like a slow-to-main jet transition?

charlie55 · Post by **charlie55** » Mon Sep 29, 2014 12:38 pm

PeteH wrote:Oh, carp. Sorry. I was thinking of another Buddy-won't-start thread. No big. Same advice: check the jets one more time.

The top half of the carb is where folks sometimes get themselves into trouble. The rubber diaphragm in the upper section can be a little fragile, or can crack/split/rupture if reassembled incorrectly. If your jets are clean, the problem might be 'upstairs', but start with the easy part (the jets). As far as cleaning goes, carb cleaner is good, but can be messy in spray form.

You can clean the jet out with a very fine piece of wire (like a guitar string), but be careful - the jets are made of soft metal (like those bowl screws) and are a precision device. Don't ding 'em up. You might pull them out and soak them in some carb cleaner overnight, just to loosen things up, too. Don't worry too much about compressors and such. Wipe off the outside, then 'put your lips together and blow' (as Lauren Bacall once said).

So to get this straight, it starts and idles, is funky at 15mph or so, but runs better above that speed. Team America: does this sound like a slow-to-main jet transition?

Yes it sure sounds like a slow jet problem.

If you can get your hands on some very fine brass wire, use that. It's soft enough that it won't scratch the jet passage. If you can't find any, try stripping a length of braided copper wire and using that. Keep removing strands from the wire until it passes through, and then keep running it through the jet while twisting it.

For tough clogs, I let jets sit overnight in pure acetone. However, if it's a really nasty one, it's sometimes less aggravating to just get a new jet and start fresh.

ucandoit · Post by **ucandoit** » Mon Sep 29, 2014 7:01 pm

Thank you PeteH and Charlie55 for the advice/info. It will be a few days until I can get to the carb. again.