1983 70hp top cyl has fire not running

[mullet_inn]

"Rebuilt carbs top cylinder no

"Rebuilt carbs top cylinder not running, will run on the bottom two cylinders just will not idle.

Any Ideas?"

 

[not-a-studebt]

Must be a fuel related issue o

Must be a fuel related issue or compression.What is the cylinder compression abd do you you have crankcase compression??????????

 

[mullet_inn]

Compreesion is fine on all thr

Compreesion is fine on all three cylinders. What is crank case compression?

 

[not-a-student]

Crankcase compression is the f

Crankcase compression is the first stage of the way a 2 stroke runs.First the air fuel mix is drawn into the crankcase and compressed on the piston down stroke it is then " transferred " into the cylinder and comressed again on the piston up stroke.If you have a bad / broken reed valve on the top cylinder( no crankcase compression ) it will not tranfer the fresh charge to the top cylinder. With plugs removed you should hear the " poof poof poof " of all three cylinder as you turn the motor by hand.Also check that spark will jump a gap of 7/16" or better at each plug.