Acts like fuel issue but I am lost! By steve (Read 689 times)

[steve]

150cc Ice Bear Viking. Did the usual PDI - oil, tranny, wires. I also replace the coil, CDI, plug, and fuel filter as part of my PDI on all of my scoots. She ran great until yesterday when she just quit. This is with only 19 miles on her. Replaced all of these again but still have the same issue.

She will start and run rough for about 10 to 30 seconds and then stop. No rev slow down - just stop. I can not apply throttle either. Pulled the fuel line from the carb while cranking and she is pumping fine to the carb.

I don't, know where to look next! From my years in electronics, I know that everything has weak design areas that are prone to failure so that's where I look first, but I think I've covered most of those mentioned on the scooter forums.

[ellpee]

Are you running at altitude? I just had a problem with a bigger Ice Bear at 180 miles, spark plug was all crudded up due to -- yet to be confirmed -- too-rich fuel mixture. I'm running in the 6000'+ range, so if you're down in the flatlands, disregard this.

[steve]

Thanks for your response. Texas, near DFW area. Vendor is jacking me on the MSO, so I've been riding in the parking lot looking for things that fall off and getting a little "chain time" so that I can tweak that adjustment.

I changed the fuel filter before I started it the first time but there may be some crap left in the carb from manufacturing.

I am the building tech for a extended-stay property and am required to live there. We allow no auto repair work on the property, so I am limited to doing minor work on the scoot. I still may pull the carb this week-end. I am trying to check the simple stuff first.

[ellpee]

Well, if you're in/around Dallas, ain't no altitude/mixture problem. Still, if you haven't done so, pull the plug, stick it in the boot, touch it to ground, crank the scoot and see what the spark looks like. Easy, cheap, and something I should have done right up front in diagnosing my problem.

PS -- who's your vendor? If it starts with E, PM me. I have a tale to tell about a certain vendor ....

[steve]

Checked fuel/spark first thing, but will concentrate on carb for now. I don't think it will take much to pull, but I've never gotten one work after working on it. Back in the day there were "carb artists" who specialized in tune/ set up on carbs" Sure wish I had a portable scope for electrical issues. but can't justify the cost.

Vendor starts with "S." 3 scoots. First, no problems great service. Second, wrong scooter, missing water pump bolt and chassis covered with road oil. This one ordered 6-20 and still waiting MSO. After this many purchases, I've learned the secret to happiness is low expectations. I have come to think of these as a hobby/project more than transportation.

Well, let's add one more WTF to this scooter. Just tore up the kick start system trying to save the battery. Think I'll just pull that and plug the hole in the CVT cover. Guess I need to lower my expectations a little more, cause it has 19 miles and isn't even titled yet.

[marcystoy]

I also had similar issue, but mine ended up being a bad vacuum tube to the carb. Did you replace you vacuum lines also? Just to be on the safe side I also replaced my fuel line also.

Don

[steve]

I replaced CDI, coil, spark plug, fuel and vacuum lines, fuel filter, fuel pump. Plug tip was black and with only 19 miles, I think it is the carb for sure. Acts like she's flooding out so it might be the float sticking or one of the jets. I'll have to look up which jet but how close would I be if I guessed idle jet? I have a new carb on order. They're pretty cheap and I'll have this one to learn on.

Last update! Found the problem, I think. I pulled the engine cover plate to do some upgrades and then it rained for 4 days. The air intake points up so I think that the air box filled with water. I will install a 90 elbow so that doesn't happen again. I may use vacuum cleaner hose so that I can add a little ram-air effect.