35 hp Evenrude engine knocking at high throttle

[Playtime01]

Starts fine, idles fine, runs great to half throttle. Three quarter throttle to full trottle the engine makes a fairly loud knocking noise every 5 secords. Anyone have any ideas? How would I fix it?

 

[tx1961whaler]

Re: 35 hp Evenrude engine knocking at high throttle

Is the engine lurching or jumping when you hear the sound?

 

[Playtime01]

Re: 35 hp Evenrude engine knocking at high throttle

Yes, both and it sounds loud enough for the motor to jump right off the back of the pontoon every 5 seconds at full throttle.

 

[tx1961whaler]

Re: 35 hp Evenrude engine knocking at high throttle

Sound exactly like the clutch dog in the lower end is worn out. That cause it to momentarily jump out of gear. Get it replaced, or you'll be needing an expensive gear set.