XR50 will not rev up...... Frustrated!! Bummed out 8yr old

History: This is a 2000 XR50 that my son sank in a very deep puddle earlier this year. I pulled off the air box and cleaned it out and installed a new UNI filter. I also cleared out the exhaust and pulled the ignition cover off and dried it out with wire dryer. It ran after that however now about 2 months later (we just haven't had a chance to ride) it will not rev up. It seems to only want to run with the choke partially on. If I take the choke off, it dies. Put the choke back on and it runs.

This week I put in a new spark plug, took the carb all apart and did find some debris in the bowl. I cleaned all that out and took the entire carb apart. I was able to use carb cleaner and spray it into every hole with it flowing cleanly through and coming out other orifices in the carb (nothing seems clogged). I also removed the intake manifold and made sure there weren't any dead fish in there but it still won't rev up.

The spark seems very blue and pretty snappy to me, I am just Frustrated that it will not rev up. With the choke all the way off it just dies when I give it throttle. The air mixture screw is on 1 1/2 turns out from snug. Please help!!

I guess, like a new main jet? From what I could see, the main jet was the only one that I believe could be changed on this bike.... I think the others are all just screws. Not really sure though as this is my only 4-stroke bike.

tepco said:

Pilot hole is tiny and is usually the culprit if it doesn't pull off the bottom.

Click to expand...

I need to figure out which one is the pilot hole..... How do I identify it?

OK, I took the carb apart again and put a piece of wire in the hole and then squirted some more cleaner into the air screw hole. I then blew air into the air screw hole and then put the whole thing back together. It now runs and pulls fairly well. I messed some more with the air screw setting and got it to run better. I think because it is so hot outside that it probably needs a main jet change to be perfect, but that is not what this bike is for. Currently it is for a 8yr old girl to ride and she will be happy with the way it is right now.

Thanks for all your help. I think this is a successful repair. :)