I've replaced motor and carb on my coolster 49 cc bike still will not start has spark has compression will fire up if I put fuel in cyl or use a shot of ether. Now what experts

SOURCE: NO start

Make sure you are getting gas and spark, they are a few ground wires that come off of injector harness that if they are not grounded will cause injector NOT to pulse re-check wiring and get back to me. Good Luck

SOURCE: Sym Jet euro 50 wont start

if you put to much fuel in the pot you might have flooded it....did you take off the fuel line to make sure you have fuel comming out?if it is not fuel injected.than try changing the jetting in it.does the plug have wet oil on it when you take it out or what color is it?

SOURCE: 46 cc Sears/Poulan chainsaw will not start

Four things I can think of:
1) There is a short in your spark plug wire. When you bend it to connect the plug in the machine it allows the exposed cable to contact the engine block. Examine the wire all the way to the coil.

2) Flywheel key is sheared ( you obviously know how to take off the flywheel since you checked the seals).

3) Flywheel air gap is not set correctly. Loosen the coil. Put the cover of a notebook or the cardboard piece of a cigarette pack between the magnetic portion of the flywheel and the coil. Tighten the coil down. This will get you the proper gap.

4) Your cylinder/piston or rings are scrubbed out. Even though it passed a compression test, on rare occasions it will loose compression only when it fires. So do the following:

Remove your exhaust manifold. Look into the cylinder with a flash light. You are looking for scratches. Anything larger then a light fingernail is definite proof you need a new cylinder/piston assy.

If it passes that test do the following:

Pour mixed fuel straight into your cylinder until 1/4 full. Slowly pull your saw over while looking into the cylinder. If you see bubbles after the ring/rings go by then you need a new cylinder/piston assy. On rare occasions if no scratches are present on the cylinder wall or piston, you may be able to change just the rings.

First if you can get a inline spark tester so you can see if your getting spark with the plug installed.

SOURCE: Craftsman 4 Stroke Trimmer

make sure fuel is fresh and carb is tuned (there are adjustment screws that are "locked".. illegal to unlock, but can be done.

SOURCE: WON'T START .IS 70# COMPRESSION ENOUGH. SPARK AND

70psi compression indicates it's rebuild time; the compression should be double that. You can confirm what the compression should be with good rings by putting a few drops of oil in the spark plug hole and testing compression "wet". That figure will be what a new saw would have.