No full trottle on my 50 merc 79 2 stroke

[Mercury 50 2 stroke 4 cyl]

eIt runs great but is struggle to make it idle before hot. and with full throttle it starts to wiggle up and dwn with rpm and i get 15 knop speed, last year 25 knop i!. When take 1 inch of throttle it runs great.

 

[flyingscott]

Compression and spark test need to be done