150cc BMS grandprix idles but dies when throttled By pukatan (Read 457 times)

[pukatan]

Hello, and hope someone can help me out! I purchased a 2008 150cc BMS grandprix scooter for my wife that had been sitting for about 3 years! I automatically removed the carburetor and it was a train wreck, so I soaked it 4 different times, blew it out with compressed air and carb cleaner,then flushed the fuel system and made sure the fuel was getting to the filter! After mounting the carb back, it cranks fine and idles, but when applying any throttle,it shuts off! Where do I go from there? Please help!!!!

[JR]

Sitting three years probably means the diaphragm in the carb is toast or in this case the high speed jet is still clogged. When one adds throttle to the carb you move from the idle jet to the main jet and just like you mentioned you can idle fine but when you give it gas it dies, classic stopped up main jet.

When you soaked it did you remove both jets to make sure all the tiny holes were unplugged. If not then time to do it again.

.thescooterprofessor.proboards.com/thread/357/gy-6-basic-carb-cleaning" rel="nofollow" target="_blank">.thescooterprofessor.proboards.com/thread/357/gy-6-basic-carb-cleaning

 

JR

[pukatan]

Yes sir,I removed all jets and everything looks good on that end, and also, diaphragms are still pliable and appear(After holding them up in the light) to be without tears or holes! I tried to start it up this morning and smell gas really bad and now it is not wanting to crank! I have gone through all of the vacuum hoses and checked out the air box and filter which all were clean! Maybe valve clearance..... Without a manual I have no Idea what to even set them at!

[pukatan]

I removed the carburetor once again and the airbox intake tube was very wet with gas! I have  disassembled the carb once again and am soaking it with hopes there might be a passage in the housing that might still be blocked with grime! Would the automatic fuel enrichment circuit (choke) being bad cause these symptoms!

[pukatan]

Thank you JR for posting the videos! I have cleaned many a carb in the past year and was laughing when I saw the videos posted! But since you had taken the time to help and post them, I watched! Anyways, in one of the videos a technician disassembled the carb and made a point to remove the emulsifier stop in which he did with a carb cleaner straw. Dang, I always replace that stop when I put a kit in one,but always have to force it out with a small wooden dowel that I keep in my tool tray! To make a long story short, that stop was not in the carb when I first put it back together and never missed it untill watching the video, but do remember while I was blowing out the housing. hearing something ping against the shop wall! Yep, that little stop! I got creative and found in my box of goodies, the one from a Honda 200es and used it as a replacement, and "BAM" scooter runs and accelerates!! It just goes to show, you have to pay attention and never be to proud to ask for help! Thanks to JR, my scooter lives............

[JR]

Awesome!

Now don't be a stranger! Let us know how she's doing!

JR

[alleyoop]

Good to hear you are up and running and a happy camper. Yes that Needle Guide sometimes falls out and you may not notice it. Many do not know where it goes and also which way it goes in. I had one guy cleaning his carb on the grass and it fell out and after I finally had him send me pics of his carb from every angle I noticed the guide was missing. Then he had a heck of a time picking through the grass trying to find it and he finally did.
Alleyoop