Carbs leaking out the overflow.

[John Schmidt]

Not mine, posting this for a friend. His I/S had sat for quite some time(a year or more as I recall) and when he finally decided to ride it...guess what; didn't want to run right.  He pulled the carbs and cleaned a fair amount of junk from the bowls, replaced the slow jets with new as well as the float needles. Put it all back together and shortly it ran lousy again...had to use the choke at low rpm, and one side appeared cool to the touch. So he pulled the tank and flushed it out good, don't recall all that he's done, still ran bad...not rideable in any case so can't even ride over to my place. He asked...so I went over and did some checking. We pulled the carbs again and the right side slow jets were completely plugged again, most likely from junk already in the delivery system from the tank on down. He ordered and installed new #38 slow jets, I helped him install the carbs again and the bike cranked up and ran great for a few seconds before I noticed is was dripping fuel on top of the engine. We shut it down and after he pulled the carbs again, decided to empty the bowls and open them up again. He discovered three of the carbs were letting fuel run out the overflow tube...which to me sounds like the needles aren't seating to shut off incoming fuel. He pulled the floats on each one and checked to see if the new needles had been damaged accidentally...looked good. He sprayed cleaner in the seat and cleaned them out with a cotton swab, didn't seem to get much though. Put the bowls back on and set the carbs on the floor with an external tank hanging above them to simulate fuel flow. This time two other carbs overflowed, and one of the first three did. The slow jets are new #38's, the float needles are new, it appears they aren't shutting off the fuel though. All the floats are good, no fluid in them to affect the float level. Since I wasn't in on all the work done prior to my coming on the scene, I can't attest to all that was done or how it was done. But based on what I've seen...I'm kinda stumped. I still go back to the floats not shutting off, has to be some debris in there he's not seeing.

I'm open to suggestions and so is my friend. He's getting tired of pulling the carbs...can't say as I blame him since he has to work in the summer heat to do it.

[Pete]

It has to be floats or float valves, bad, mis-installed or contaminated with something.
Are you sure that the float valves are correctly installed on the floats.
And that no floats have broken or mis-shaped tabs (where the float wire rides).

When cleaning carbs clean like surgery.
Check the tank and flush the entire gas system, as it could have rust that re-contaminates the carbs.
Clean til you get it right.l

[John Schmidt]

I think I'll call him and suggest he drop the carbs off on his way to work tomorrow. I'm retired so have the time and tools....and my garage is air conditioned.

[Thunderbolt]

maybe a tad shorter and not quite sealing?  Otherwise, they are probably out of adjustment or contaminated.  Possibly contaminated seats from some chemical and have hardened.

[John Schmidt]

maybe a tad shorter and not quite sealing?  Otherwise, they are probably out of adjustment or contaminated.  Possibly contaminated seats from some chemical and have hardened.

Terry, I wondered about that so asked if he still had the old ones. He dug them out and said they looked exactly the same to him. The thing is....they only have to be a fraction shorter to cause a problem and you can't really tell without using a micrometer to measure them. I talked to him this evening and he's dropping them off on the way to work in the morning. I may not find anything, hopefully I can pin it down though.

[Robert]

A couple of things come to mind the float needles may be good but the seats still may have deposits on them. I saw that you cotton swabbed the seats but just check that the needles dont bind on the sides. I agree with checking the needle length and did he bend the tab on the float? I say when you get them go over them with a fine tooth comb. Also check to see if there is any gas in any of the floats maybe some are no good. From what I have seen with the carbs I have taken apart after using this ethanol gas it leaves a coating on anything that sits in it not easily seen and really hard to get off. It will bind the float needles.

[Ricky-D]

There is nothing associated with the float/needle that is adjustable.

There are no tabs to bend (to adjust) nor seats that can move.

Everything is pre-engineered to work without adjustment.

Sounds like the problem is poor reassembly practice!

***

[Patrick]

There really is nothing to adjust,, so,, it kinda sorta sounds like a contamination issue.. It doesn't do much good to clean the carburetors and then fill them with dirty cruddy fuel.. Seems like things need to be cleaned properly again including the tank and install an in-line filter..

[John Schmidt]

Used some Techron spray carb cleaner, there's a lot of brown residue in the system. I finally took out all the float needles and stuck a cotton swab in each hole. Then soaked them with the Techron and let sit for a couple hours while I ran some errands. Later, with the end of the swab still in place but the stick removed, I used a tiny jewelers screwdriver to spin the swab back and forth in a rotating scrubbing motion. Got some more brown junk out in that procedure but I think I need something even stronger than the Techron...any suggestions? 

I did put them back together and set the carbs over an oil drain pan on the floor, then hooked up my external testing fuel tank and hung it on my bench vise. Turned on the feed line fuel petcock and waited...in a few seconds the right bank overflow starting running fuel out. I tapped the bowls with a screwdriver handle and the fuel stopped flowing out the overflow. It was also dripping slightly from the output side of the carbs on the #1 & 3. I tapped the bowls again and it seems to have stopped...been sitting for over an hour now. I'd still like to get some stronger cleaner so need suggestions. The way it is I wouldn't use them yet, setting a person up for hydrolock.

[Pete]

Gumout Spray carb cleaner seems to work well for me, but even with it sometimes it must soak and/or be brushed.

Have also use Berrymans, seems about the same as Gumout.

Sometimes on the first fill after being apart and upside down a float will stick. Tapping as you did will release it

Drain the carbs without turning them over, refill thru the gas line and see if they are sealing.
Do this check several times until you feel confident it is sealing or is failing.

[John Schmidt]

He's ordering new float jets/seals...the ones with the little rubber tips anyway. In the mean time, I'll just keep soaking the area they sit on....figure I have most of a week. I got them to the point of little or no drip from a couple on the right bank. I'm not satisfied with that, hydrolock in the making. I'll post my results when done.

[John U.]

According to their lables Gumout spray contains acetone,xylene, methyl ethyl ketone, petroleum distllate, and propane.
Berrymans contains toluene, methanol, acetone, 2-butoxyethanol, mixed xylenes, isopropanol, and methyl ethyl ketone.
Pick your poison, but I think either of them will be unfriendly to rubber.

[Pete]

According to their lables Gumout spray contains acetone,xylene, methyl ethyl ketone, petroleum distllate, and propane.
Berrymans contains toluene, methanol, acetone, 2-butoxyethanol, mixed xylenes, isopropanol, and methyl ethyl ketone.
Pick your poison, but I think either of them will be unfriendly to rubber.

Been using Gumout Spray  for years with excellent results.
Point well taken  -- letting rubber diaphrams soak in it will not make you happy.
Spray cleaning o-rings and and float valve tips, does a good job.
May affect some plastics so be careful with them.
I only soak metal parts in Gumout.

[Robert]

Accidents do happen and the float tabs do bend and can be adjusted. sometimes unknowingly with some rough handling some have indeed changed the float height.
  I recently took some carbs apart and found a green residue on all the parts that where in gas, It looked like the color of the pretreated wood you buy in home depot. Nothing including all the aforementioned things would remove the coating. So I got some toilet bowl cleaner and let the jets soak in that for about 10 minutes and it worked great. You need the acid to do the job, The stuff they use to scrub the bowl to make it white. I think I used snow bowl. The deposits must be from the ethanol because I haven't seen anything like it before. It will not come out with any of the cleaners that we usually use its almost like it was baked on. Use this only on the jets or the seats nothing else obviously.
If anyone lets their bike sit and doesn't put something like store and start or drain the fuel their in for problems. Havent taken enough other carbs apart to tell if this is a isolated incident or what we are going to be in for but I was almost ready to replace anything that had been sitting in gas. John clean everything really well blow out the passages in the carbs and clean the jets. I know that you have already done some cleaning but dont let the guy go with any chance of the floats sticking. Because I would hate to see the guy get a hydrolock after this. Not to mention if you clean everything now you wont be doing it again.

[lee]

For cleaning small carb parts I have found that Lacquer Thinner is about the best
thing you can use.