High rpm surge problem with youtube video.

[tlivingd]

I've got a 1989 Elite 50 (the SB50). It ran great last year. It sat over the winter and then wouldn't run right. I did the following trying to correct the problem.

drain tank and fresh fuel,
carb cleaning,
spark plug (yes went NGK had at .028, it's now .025)
carb cleaning again, forgot the emulsion tube.
reed inspection,
Cleaned and oiled the air filter sponge that is still in good shape(used 10w40 per service manual)

But now I'm stumped. Once the engine is warm it surges and loses power.
When cool it is groggy and will nearly stall when giving it a fair amount of gass, until it warms up that I think is fairly normal.
Pulling the plug it looks lean.
I'm not sure what else to check. for this condition.
It starts super easy (one kick when cold)

Please see the video http://youtu.be/yVZ6zpk8HJ4

[Wheelman-111]

Greetings:

I believe it's likely you'll find an air leak somehere. Try the carb mount first. Exhaust flange gasket? Base or head gasket weeping? Hope it's not crank seals.

[tlivingd]

Is it possible to propane sniff with a 2 stroke like you can with a 4 stroke engine?

[Wheelman-111]

Greetings:

I've done it many times to check at idle, but some of these leaks only appear with vibration/road bumps. Jiggling the carb might uncover a leak at the brown plastic insulator - a common culprit.

[tlivingd]

Update: Messed with it some more. It would surge at mid throttle too. Anyway, After removing the carburetor a 3rd time, I soaked it in some toxic waste in a can. I had an old can of Berryman carb dip buried in the back of the garage. Left the parts in it for 15 min. Upon removing the carb, some parts that looked clean now had a crinkled look like bad paint. Got the Qtips and pipe cleaners out, sprayed it out again to remove the Berryman, then reassembled.

Once it got fuel in the bowl, it fired right up. Warmed it up, adjusted the air bleed screw, and took it a few laps around the block. No problems.

WOOHOO!
-nate

[patthesoundguy]

Right on! I bet that feels good to have sorted out, now you can get to putting the miles on

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