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I'm trying to fix a 33cc 2 stroke motor on a scooter. I brought it home (found it at the salvage yard, yes I know I'm a dump rat), put gas in the tank, primed it, and it fired for about 3 secs than quite. Couldn't get it to pop or backfire after that. Poured gas down the cylinder and couldn't get it to do anything. There is spark, new plug is gapped to .025. There is no air filter on it yet. I went through the carb and cleaned it but didn't really see anything out of the ordinary. I'm getting about 90 psi compression, seems enough to at least get it started. Couple questions



Should the diaphram be sitting right on the needle lever or should there be a gasket then the diaphram? Same with the fuel pump, should the fuel pump be sitting right on the aluminum or should the gasket go in between the aluminum and fuel pump? Or does it vary?


Is this normal.......Checked the spark by touching the spark plug to the cylinder. I'm cranking the motor with a 9.6v cordless drill. It only sparks when the drill is at its max rpm, when I run the drill at half rpm, no spark.
 

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There should be a gasket then the metering diaphragm, on the pump side the diaphragm goes directly against the machined surface then the gasket and the pump cover.

It should start with 90 psi, check the cylinder and make sure its tight, check the seals on both side of the crankshaft, a major air leak into the crankcase on a 2-cycle engine will keep it from starting even if it has good compression and spark.

Most CDI ignition will not generate a spark at low rpm's this is not unusual
 
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