ATC90 question

[ATC90guy]

Hey guys,
My ATC90 was running fine until the other day when it started bogging down and it quit. Cranked it over, it would try to fire once but wouldn't start. Finally got to the point where it won't even try to start now. I cleaned my carb because I found rust in the side filter on my ATC 90 and stuck it back on. Tried to crank it and it won't fire off. It looks like I am getting good spark (bright and blue). But I found that my intake valve adjustment screw had come loose and was way out of adjustment. It came loose while it was running. I adjusted it back to spec (0.002 in) and tried to start it but it still won't fire off. I hope I didn't burn the valve, and I can't figure out why it won't start. Any ideas? Also I do have rust in the tank but I was wondering how can you get all the rust out? Thanks!

[Rex Karz]

This probably won't help much, but You have to set your valves cold. If an intake valve is adjjusted where it didn't close all the way, it would backfire. If an exhaust valve is adjusted where it didn't close all the way, it can burn it. Has the 90 ever been bored and re ringed? Lots of 3 wheelers lose compression gradually to where they just won't start. Have You checked the compression? Can you smell gas in the tailpipe?

Tried to help, good luck!!!

[Rex Karz]

[dann]

take you tank off and drain it then put a hand ful of bolts and nuts into the tank and shake like hell then dump them out and rinse it with water always works for me

[ATC90guy]

Rex,
I set the valves cold and it ran fine. Until the adjustment came loose on the intake valve. So I guess it when the adjustment came loose it closed off and wouldn't let any fuel in. But I re-adjusted them cold and it still won't start. It has been re-ringed and bored. The exhaust valve is adjusted to spec and has been ok. It has a brand new spark plug in it, gapped to spec. I don't see how the intake valve not opening could burn anything up. I am going to check compression tonight when I get home. Hope this helps. Thanks Rex.

Dann,
Thanks for the tip, I will try that. Thanks!

[jenndnn3]

You can check your intake via the carb. Take off ai filter, have someone pull the recoil, while placing your hand over the back of the carb. If you are sucking with no blow back your intake should be fine. If you have blowback, then your looking at a possible not set right, or blown valve, bad timing anything that would cause that valve to work at wrong time.

I learned a nifty trick this weekend, thanks to the great folks of sandwizards, that sometimes setting at pure TDC doesnt work. Sometimes you need to roll through each rocker individually loose and set them that way. And then recheck at TDC

Oh yeah WELCOME TO THE BOARD!!

You missed a killer weekend out at Florence this last weekend, perhaps you may join us for the next one!

[ATC90guy]

Jenn,
Thanks for the help. I will check and see if I have vacuum at the carb. Thanks for the welcome, this board has been a big help. Florence isn't too far from where I live so I might take ya'll up on that one! Thanks again!