Kawasaki Vulcan Forum banner

carb issues, overflow, excessive fuel

62K views 10 replies 5 participants last post by  1964lguillory 
#1 ·
1996 Vulcan 800 classic...I work on this bike for a good friend and just had it hauled to me for some work. She complained that gas was flowing from it and dripping from the engine. Then it was mentioned that the "little bottle" was full. Ok, I said it sounds like the float is sticking. Well, upon checking, yep, you try to start and the gas starts to flow out the overflow..I tapped on the carb and it appeared to stop and though maybe just a little gunk on the seat/needle. The spark plugs were gas fouled and the cylinders were loaded with gas. I cranked the motor a few times to blow out the excess fuel, cleaned the plugs and reinstalled. Bike fired up, but had trouble idling with air cleaner cover on. After a bit it seemed to be ok. I dumped some fuel cleaner in the tank and set out for a test run...well, didn't make it far..got about 1/2 - 3/4 mile up the road and started losing power, then some knocking and then died. Air cleaner cover was hot! Let sit for a couple of minutes and pulled cover off -- yep, I was on fire a bit..I tried starting the bike and it would start, but would continue to backfire through the carb if any throttle was applied..I'm suspecting that the carb is still dumping too much fuel in the cylinders, hence a rebuild is order....thoughts, suggestions, recommendations?
 
#2 ·
follow-up...I pulled the carb and while doing so, I found that the petcock is allowing some fuel to pass on its own. Also, there was a hose loose from the air filter housing to a vacuum valve, which looks like some vapor recirculation system..I don't think that the latter would have any affect on the problem at hand..Anyway, I disassembled the carb, cleaned all the jets and ports, inspected the slider diaphragm and removed the float/needle. Everything looks good, except there was quite a bit of dirt build-up in the bowl. I ordered a new float and needle anyway, just to cma. I'm also repairing the petcock and replacing any hoses that look bad...will post back when I'm done with that...in the meantime, anybody have some other suggestions for things that I should do while I have it apart?? Jeff :)
 
#4 ·
well, I installed the new needle valve and float.I checked and set the float level(which I checked again once installed on the bike). Everything went together great. The bike started up and idled fine. BUT...after taking it up the street and back, the bike started to idle slower and rougher when I parked back at the garage. I turned off the bike and removed air cleaner cover...still had excessive fuel in the carb!!! Well, now I'm back to square one...,,here's the thing...it idles fine without flooding. It only happens after it's been driven or throttled, then stopped at idle is when it starts to flood. So, I'm thinking that maybe there's happening at deceleration, like with the coasting enricher, or startup enricher. It could be something unseen inside the body of the carb that could be causing a problem. Being unfamiliar with this carb doesn't help much. So, if all avenues are exhausted, I may be going to another carb..
 
#6 ·
well, I removed the carb again and took it apart to re-do everything . I removed and checked the diaphragm for the coasting enricher and removed the main needle jet and needle, remove the pilot jet. When I held up the pilot jet to check the opening, I saw some light through it, but not much. I blasted the jet with carb cleaner, and when I looked again, it appeared that the opening was larger. So, I'm thinking that might have been still slightly clogged. Also, I put the tube from the carb cleaner down into the tower that the pilot jet was removed from, and I added some material to pack around the tube, so that it would seal the opening and force pressurized cleaner through the port and out of the openings in the venturi. I also blasted the starting enricher (choke) bore as well. A got the bike to start up and it idled well. I don't know if it is typical, but this particular carb/engine does not like to run without the air cleaner. Some of it could be the exhaust pipes that were put on it, but it seems there is too much air for the carb and it backfires the through the carb. So, I just cover half of the opening with some masking tape to meter some of the air going into the carb...
I took to bike up the street and back a couple of times and opened the air cleaner and checked for fuel. It was dry at this point. I proceeded to fully assemble everything and took it for a ride again down to the gas station to fill the tank. After I stopped to fill the tank and when I went to start the bike again, it didn't fire after a couple of cranks. So, I was thinking I had the problem back again. I checked the air cleaner and it was dry. I tried to start again and it fired up, but it was idling a little low. I had adjusted the idle when it was fairly cold, so it might have been that I had it adjusted incorrectly. The no-start problem might be from another problem with the ignition switch that happened recently, I'm not sure at this point. Tomorrow will be another day, weather permitting. All take it out again and see how it does then.
It conclusion at this point, make sure that the pilot jet port is cleared, as well as the jet itself. Also check that the petcock is not leaching gas while the bike is parked. Check by removing the main gas line. The petcock should not allow fuel to flow when in the reserve and on positions, only at purge. Mine was allowing some fuel out, so I replaced the packing and the o-ring on the vacuum diaphragm.
Stay tuned..
 
#7 ·
Final report...it seems that everything is working well at this point. I have driven the bike on a couple of 15-20 mile runs with no problems. After the first run, I did drain and replace the oil. There was quite a build-up of fuel in the crankcase. If you are having flooding or rich mixture problems, changing the oil is a must after repairs are completed. I think that some of the problems I had directly after re-installing the carb may have been from some poor fuel. I have added some Seafoam to the tank to help clear out anything that may be remaining. Aside from a couple of odds and ends that I plan on doing, the bike is repaired and soon will be returned it to its owner...
 
#8 · (Edited)
My experience

Just posted this in another thread, but may be useful here as well...

I had a similar experience with a flooding carb. last summer my 05 VN800a would start dumping gas (from air cleaner drain). After taking the carb out and cleaning it 3 times, I finally got a tip from a guy. He said to check the hoses coming from the carb. I followed one back under my seat, and went nowhere. It is a vent hose of some type. figured out that when I had taken my seat off to change my battery, I had pinched it under the seat by accident. And would'nt you know, when I cover the end of that hose, gas flows out of the carb. open it up and it stopped! They said sometimes bugs will get in there and block the hose also. Pull that vent hose and blow through it to be sure it is clear.

Don't know the reasoning, but thought I would share this experience in case it helps someone else.

Jon
 
#10 · (Edited)
Hose routing

Just posted this in another thread, but may be useful here as well...

I had a similar experience with a flooding carb. last summer my 05 VN800a would start dumping gas (from air cleaner drain). After taking the carb out and cleaning it 3 times, I finally got a tip from a guy. He said to check the hoses coming from the carb. I followed one back under my seat, and went nowhere. It is a vent hose of some type. figured out that when I had taken my seat off to change my battery, I had pinched it under the seat by accident. And would'nt you know, when I cover the end of that hose, gas flows out of the carb. open it up and it stopped! They said sometimes bugs will get in there and block the hose also. Pull that vent hose and blow through it to be sure it is clear.

Don't know the reasoning, but thought I would share this experience in case it helps someone else.

Jon
Interesting post. I think you could be refering to the tube that actually vents the carb to atmospheric (outside) pressure. I think it routes from a port just above the fuel elbow/inlet port, & goes rearward on bike rightside down through opening near battery then into the California box (don't know what else call that box), right side cover area.

I believe my routing to be ok, but I will certainly check for clog(s) & possible pinch off by seat re-install. THANKS :D
 
#9 · (Edited)
Same Flood Issue

Been wrestling with very same problem on my 96 800 Classic. All seem to start with "breaking" petcock over to RES(erve) on the HWY. Later I found that I did tear the selection/porting gasket just behind toggle of petcock. Small piece fouled & flood out carb. Cleaned snot out of carb! Started experiencing poor throttle so I cleaned again & checked carb settings. This time I found the accelerator pump diaphragm very rotted & ring cracked. Cost me $50 & a weeks wait. Intsalled myself upon arrival. Ran for next 200 miles without incident, then I believe I over topped tank & fouled out breather port for cap (many posts about this here). So after cleaning cap port while impatiently awaiting K&N air filter, I pieced back together. Took for a spin 1/2 block it flooded out badly through airbox! Good things are that I now have the K&N in, all the lean/EPA crap gone, a thumb adjust now in carb idle mix adjust, & a tach installed (fun accessory-one less worry knowing idle is on mark). After noticing petcock was leaking slightly in RUN position, I've since ran with a make shift fuel supply & it ran well @ idle & off idle.
At this point I've been down & off the road. I just ordered & received a K&L petcock rebuild kit#18-2728, but found it to be incorrect (though listed as Vulcan 800). Researching oldbikebarn.com I've found they listed K&L kit #18-5023 as Vulcan 800, so this Friday I plan to get it & hopefully get my baby back on the road. Wish me luck.

BTW the big PIA in troubleshooting carb flood issues is plug fouling (need to clean) & as mentioned the saturated oil (flooded out crank case). Thank goodness I've just one carb on Vulcan, my old bike (4 in-line) had 4 times the carbs that could possibly flood. I went through so much oil trying to resolve carb problems.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top