advice urgently needed please

[lmc83]

Hi
I have a Yamaha Neos 50cc scooter. I'm having a problem with it where the engine keeps losing power when I open the throttle. It then cuts out and won't start for a few minutes. I've taken it into a garage for a service and they said the carb was full of water. He cleaned it all and it worked fine for the first few miles but then started again. When I took it back he said there was more water in the carb. He thinks its being sucked in through the air filter. Will changing the filter fix this? I don't want to just keep throwing money at it if its knackered. Any advice would be greatly appreciated!

Thanx

Lisa

[Blackbomber]

Welcome to Provoscooter forums.

Are you running an open element style filter, or the factory airbox? Open element designs are notorious for clogging in the rain, but I suppose it's possible for water to get in also. I don't think much of this water would find it's way into the float bowl, however. It would probably just go through the motor.
This is purely conjecture, but I would hope the shop would have advised you about the filter, if they thought replacing it might cure the issue. Are they giving any recommendations for prevention?

[lmc83]

Hi Blackbomber
Thanks for replying. I'm afraid most of that was gobbledygook to me tho!!!
I don't know what type of filter it is - how would I find out?
The guy at the garage just said he'd show me how to empty the carb so I don't have to keep bringing it in but its only doing a few miles before it starts playing up again.
Also, it doesn't only do it when its raining. Last time the weather was fine but by the time I got it home from the garage it had started playing up again. I just don't understand where the water is coming from.

My brother has had a look at it (he's a mechanic but has never worked on a bike before). He thinks the fuel tap is clogged. He took it out an tried to clean it but couldn't blow air through it. Should the petrol be 'free flowing' through it or has it got some kind of valve in it?
Thanks again

Lisa

[Blackbomber]

Well if the bike did not come in any contact with water in those few miles between carb drainings, then I think we can safely rule out the filter for the moment. I think the water is in your fuel tank. It is probably a small ammount. Gasoline is less dense than water, so the water will sit at the bottom of the tank. Topping off your fuel, and hoping it dilutes won't work. Draining the tank really won't get all of it out. I don't think there is a reliable way to clean this all out without removing the tank. I have a post you can use as a guide, #2 in this thread: http://provoscooter.com/forum/showthread.php?t=18164 If you don't have rust and dirt in the tank, you can skip the BB's or washers, but use fresh fuel, and shake it all around. You will see the water when you drain the fuel. It will be the clear bubbles in the otherwise yellowish liquid. If you don't feel comfortable messing with this, see if your brother will do it for a round of pints. It's not a bad job if you are used to turning spanners, but for the owner that is just interested in fuel and go, it can be a bit daunting.

As for the fuel tap, the Neos uses the typical vaccum operated style. Simply remove both lines at the carb, place the larger one in a cup or container, and apply vaccum to the smaller. Applying vaccum means suck on the end of the hose. This is in the Yamaha service manual - it's official factory procedure, believe it or not. With vaccum applied, you can visually verify the operation of the fuel tap, although the water is coming in elsewhere, I'm sure.

Good luck, and post back with your results.

[lmc83]

Cheers for the advice. Will give it a try this weekend and let you know.

x

[Blackbomber]

Great, best of luck to you.