Fuel leaking from carb overflows

[jweaver]

Hello all, new to the forum, I have searched through a lot of threads and have not found quite a definitive answer to my somewhat unique problem. I have a 1991 voyager xii with 55k miles. When I got it, it ran (like crap) and was leaking fuel out of the carb overflows. Its obvious that it had been sitting a while so I immediately pulled the carbs and cleaned them thoroughly, and adjusted them after putting it back together and draining the old nasty fuel and putting in fresh fuel. While cleaning the carbs I adjusted the float height and polished the seats on all of them. After putting it back together it ran great, but still leaked. I then pulled the carbs again and rebuilt them using a cheap ebay rebuild kit with new floats and all. After putting it back together it again ran great but STILL leaked from the overflows. Then I took it to an old school carb motorcycle mechanic, who rebuilt the carbs AGAIN using OE parts to replace the cheap ebay stuff. He told me these can be very finicky with anything other than OE parts. He also jetted the carbs and replaced the fuel filter. Now the bike was running perfect, but yet again same problem, leaking from the overflows. Upon closer inspection I noticed a small amount of rust and sediment at the bottom of the tank. So I ripped it all apart, cleaned the carbs again, and pulled the tank cleaned it out and did the 3 step epoxy sealer. The carbs had some junk in them so i know it was a problem. Well I put it all back together and once again, the bike runs the best it ever has, but it immediately started leaking from the overflows. My question is, has anyone ever had a problem with the fuel pump creating too much pressure? I am at a loss at this point as I can’t think of anything else that could be causing the issue. Sometimes its just one carb that leaks a steady stream out of the overflow, and sometimes its all 4 at once. I have owned many carbed bikes and I have never had this much of a problem with them. Just wanted to see if anyone has had this hard of a time with the carbs on this bike or if it could be another issue. Thanks in advance

[triton28]

sounds to me as though you did everything correctly and should not be experiencing the spillage you described.
That having been said though, I wonder if the previous owner may have installed offshore kits in the carbs and used the supplied float hangers. I say this because Carl Leo once pointed out that these offshore hangers are slightly different dimensions and can sometimes bind on the inner walls/surfaces of the float chamber. If your mechanic used OEM hangers then you can eliminate this idea.
The only 2 other ideas which come to mind are that 1) with all due respect to your ability to rebuild carbs, possibly you may have set the float level holding the carbs too close to flat, upside down and not at just enough of an angle from vertical, toward upside down, to softly contact the tip of the float needle or 2) the back pressure detection circuitry/diaphragm of the pump may be malfunctioning allowing greater pressure than the float valves are designed to hold back. If the pump stops ticking after filling the float bowls then probably this idea is not the problem.
I bet it is something simple but that's all I have right now, it's early in the day.
Dave

[jweaver]

Thanks Dave! I know for sure the float hangers are OEM, and i double and triple checked the float setting. I didn’t know the pump has a back pressure diaphragm but it sounds logical that the old varnished fuel could have stiffened and deteriorated it. I ordered a new OEM pump and filter last night so that will be the next thing to be replaced. I will update the thread once that comes in and I replace it. Thanks for the reply. I am determined to get this figured out, this bike runs so nice and is very smooth otherwise, and I stole it for what I paid for it.

[GrandpaDenny]

At the risk of getting slapped... are the bowl drain screws closed?

[jweaver]

Yes the bowl drains are closed and I put new o rings on the screws from the rebuild kit

[Nails]

Not much help, this ... but your original guess about too much fuel line pressure is the only plausible explanation I can think of. To me, the salient facts are: the fuel is leaking out the overflow tube; and it's sometimes one and sometimes all four carbs. Hard to believe you've overlooked a problem with the needle valves, or that flooding the float bowl is from anything besides the needle valves (including more pressure than they're designed to stop -- even though I've never seen that before).

(But IIRC, all the carbs drain to a common overflow drain. How do you know all four carbs are leaking?)

As previously mentioned, does the pump shut off right? To test this, consider installing the switch that defeats the starter motor (elsewhere in this forum), and then using it. That allows powering the pump but not the starter motor. I can clearly hear when the pump starts clicking because the float bowls are full. Does the leak start while the pump is still running?

Given that you have the carbs out ... do the float bowls overflow when you hook the carbs up to gravity pressure (i.e., like a normal bike, with the gas tank actually the gas tank and no fuel pump)?

It sucks when you're trying to be good and the Engine Gods aren't playing right. It also sucks when you're reduced to parts-swapping, but at least a fuel pump is good to have in the spares bin.

Good luck.

[jweaver]

Great idea Nails! I actually never considered attempting a gravity feed! All 4 float bowls have a drain, I just don’t have the hoses that connect them and direct overflow to one spot. I am going to set up a gravity feed today and see if they will overflow. If the bike still runs and the carbs dont overflow then i know pump overpressure is likely the issue. I will update when i do this

[Nails]

All 4 float bowls have a drain, I just don’t have the hoses that connect them and direct overflow to one spot.

These are to drain the float bowls entirely. If gas is leaking out these drains (on the bottom of the carbs), then those drains aren't closing like they should. Doesn't have anything to do with overflow.

The overflow drains are separate, and they drain gas when the level goes higher than a bit above the top of the float bowls. These are interference-fit between the carburetors like the fuel line, but one way to distinguish them is they have plastic rather than metal tees. (My plastic ones were rotten and had big holes in them. But they didn't leak gas because they didn't have gas in them, because my needle valves worked and so there was no overflow gas to drain.)

[triton28]

To outline the correct function and use of the small hose nipple located on the bottom of the float bowls please note the following: with the threaded drain screw fully seated into the bottom of the float bowl NO fuel will drain from the bowl provided that the float level is set at the correct specification and the carburetors are sitting level as intended. Upon opening said drain screw any and all fuel in the float chamber will be evacuated from the bowl.
Having said that, if the float needle is stuck/held open by crud/rust/dirt or other debris, which by the way duplicates the result of a float set too high, then any and all fuel at a level HIGHER than the top of the vertical brass tube in the float chamber will drain through the said small hose nipple located on the bottom of the float bowl even when the drain screw is fully seated into it's locale. Both functions: draining the chamber AND an overflow situation will come out of the small hose nipple.
The overflow passage is directly above the small hose nipple and bypasses the drain screw body whereas the drain hole is farther in at the end of the drain screw taper.
Dave

[Nails]

Thanks for the clarification. I was going on memory, and I've slept a few times since I was in there.

I know I had a plastic tee in the carb assembly that was totally rotten -- and a pricey little wench to replace. I didn't find a useful drawing in the manual, and I couldn't see much on my assembled bike. But I remember that it didn't normally have fuel in it.

Then again, I'm overdue for a crazy spell.

[Nails]

I found a carb assembly blow-up on a parts microfiche (ZG1200_B1-B5_VoyagerXII.pdf) I surely got off this AVA website somewhere. (I don't know how to search for "parts manual" without getting a dozen pages of everything that has "parts" and "manual".)

But I still can't identify that mysterious plastic tee I've been carrying on about. Much less what it actually does. Oh well.

[triton28]

The only "FITTING,T-Type" tees shown in this illustration, and used on the Voyager XII carburetors, are: 92005-1119 which is used on California only models to connect the tubing downstream of the float chamber vent tees to the evap system and shown as 92005A on the illustration; 92005-1125 which are used to vent the float chambers and are shown as 92005B; 92005-1148 which is the fuel rail inlet where the rubber hose from the pump connects onto and is shown as 92005C; and 92005-1151which are the tiny black plastic tees used on the drain lines and are shown as 92005D.

https://www.partzilla.com/catalog/kawas ... carburetor

[Nails]

Yeah, I saw that CA insert. Maybe I have a mostly-de-Californicated XII. I don't see an evap canister -- that mysterious Tee drained in front of the rear wheel. I assumed it was the carb overflow drain. If I ever have the carbs off again (press wood) I'll try to figure it out.

[jweaver]

UPDATE
I just replaced the fuel pump and NO MORE LEAKING FROM THE OVERFLOWS. Thank you to everyone for replying with advice and insight, that is exactly why i made this post so if anyone down the line has the same issue it is documented. I have been chasing my tail with this damn thing for months and I’m happy to have it fixed for the summer to kick off. If anyone would like to know where I got the pump it was from Quantum Fuel Systems. The only fitment note I have is that the inlet and outlet flares are slightly larger than factory so keep that in mind. Installation was a pain thanks to kawasakis airbox design making it near impossible to access anything to do with the fuel system without removing the tank. If anyone has any questions about the install let me know. Thanks again

[Chris Cochran]

My question is this: How can you tell if a specific carb is overflowing since they all dump into the same hose?

[GrandpaDenny]

Disconnect the hoses from the carbs.