full throttle bogging/dying

[squirlgod]

I've tried to do my research and I've tried lots of things but nothing has quite solved my issue. My scooter starts fine and runs great for a few mins, and then once its warm it starts to die at full throttle and low speeds. It seems to be especially bad after holding a steady 30 mph for some time. in some cases it even dies right after you let off the throttle if you've been holding it for a while. After it cools down it runs great again until it's warm. I replaced gaskets and cleaned everything recently, except the air filter, and tuned the carb to the best of my abilities. What is my next step!?

[squirlgod]

bump?

[DickB]

It sounds like it is running too lean. Is it a Spree? Clean the air filter, then make sure that the airbox is all there, tight, and you have no air leaks into the carb.

[Bear45-70]

Actually it sounds more like it is running out of gas, which makes you go lean, but it is not the jetting. It is low fuel level in the float bowl. Try loosening the gas cap, to see if it helps. If it does the vent's in the cap need to be cleared. If not, then you fuel filter id partially plugged and/or the petcock is plugged.

[squirlgod]

These are all good Ideas I'm going to try all these suggestions and get back to you. The only other thing is that the previous owner put an inline fuel filter from the tank to the carb. Could this need replacing as well?

[Bear45-70]

These are all good Ideas I'm going to try all these suggestions and get back to you. The only other thing is that the previous owner put an inline fuel filter from the tank to the carb. Could this need replacing as well?

Yes, replace it but not with just any filter. Honda sells one they use on the Aero 125, so you will not have any flow restrictions with it.

FILTER, FUEL 16910-GB2-900 $8.04

[Pete M]

Have you replaced the spark plug?

[Bear45-70]

You pull the plug wire cap off, put a spark plug socket on the plug and unscrew it. When you install the new one, remember that it is an aluminum head you are screwing the steel spark plug into and if you get carried away you will strip out the head.

[squirlgod]

I have a spare plug laying around but the current one has a strong spark and was replaced shortly before I bought the scooter.

[Trafficjamz]

sounds like the pilot jet on the carb is plugged up.

[squirlgod]

Ok so it is def a problem with fuel delivery. I was riding it today and once it got to bogging I took a look around the engine...the fuel filter was empty. I took the line off the filter at the inlet and fuel poured out. I took the fuel filter off completely what fuel was left in the filter drabbled out pretty quickly. The only thing I forgot to check was loosening the tank cap but fuel was coming out no problem from that line so I wouldn't suspect that. Is air getting up in the filter from the carb or something? How is it empty even though there if no resistance through the line....petcock bad?

[Bear45-70]

Ok so it is def a problem with fuel delivery. I was riding it today and once it got to bogging I took a look around the engine...the fuel filter was empty. I took the line off the filter at the inlet and fuel poured out. I took the fuel filter off completely what fuel was left in the filter drabbled out pretty quickly. The only thing I forgot to check was loosening the tank cap but fuel was coming out no problem from that line so I wouldn't suspect that. Is air getting up in the filter from the carb or something? How is it empty even though there if no resistance through the line....petcock bad?

First off, the petcock should not allow fuel to flow with the engine off.

Second off, if the fuel filter was empty, it is either a bad fuel filter of a tank vent.

Yes it could still be a tank vent issue.

Air could get into the filter from the carb, but only if the fuel flow was so low as to drop the fuel level in the bowl that the needle was open and no fuel was coming in to fill the carb, so that ain't the problem.

I doubt the petcock is bad but to prove it you will need to check the vacuum at WOT then check the petcock at that vacuum level to see what the flow is.

[squirlgod]

Ok so I'll replace the filter, check the vent issue, and then look into the petcock. I do find it strange that the fuel flows out with the engine off...i'll get back to you.

[squirlgod]

Ok so I'm getting real confused here...

I replaced the filter and tested with the gas cap off with no improvements. Here is whats happening:
with nothing to block the end of the fuel line it will just pour out forever, but when hooked up to the carb the fuel filter wont fill up at all (or at least not at a noticeable speed), but sucking on the petcock vacuum line also feeds no fuel into the filter....sooo petcock?

[squirlgod]

Im stumped here haha this has to be the petcock right? is it possible that the vacuum to the petcock is stoping the flow of gas instead of doing the opposite?