1996 Mercury 60hp big foot

[EVANGL]

Gday All
My bigfoot gearbox is knocking in forward gear(only)and thats with the muffs on.
Can i replace the big foot box with a regular recondishend box, as they seem to be cheaper?

Thanx
Gl

 

[achris]

Re: 1996 Mercury 60hp big foot

Sounds like you have prop chatter. Does it do it in the water? If not, you may not have a problem.

 

[EVANGL]

Re: 1996 Mercury 60hp big foot

I put the leg in a drum of water and put it into gear,there was no more knocking. What exactly is prop chatter?

 

[achris]

Re: 1996 Mercury 60hp big foot

If there is no load on the prop then the shaft can free-spin ahead of the engine speed. As the engine speed rises and falls (just a few revs is all that's needed) the dog clutch will go between drive and overdrive (much like a car rear diff if you oscillate the throttle)... What you are hearing is the clutch catching up with the propshaft, hitting it, then the shaft spinning faster again... Very common on 2 stroke engines, as at idle they do tend to hunt slightly. When the prop is in water it creates a load on the blades, so the prop can never be 'ahead of the dogs', so they are always 'hard engaged'..... If there's no noise with the engine in NEUTRAL, and none when the engine is in FORWARD or REVERSE when it's in the water.... There is no problem...

BTW... You shouldn't be engaging FORWARD (or REVERSE) out of the water...

Chris........

 

[EVANGL]

Re: 1996 Mercury 60hp big foot

Thanks Mate it is appreciated.