what is max revs for suzuki 140 4stroke?

[Tris]

as above? a mate has a ring rib he said it feels slow and does not rev over 5500?

[Frenchbruno]

http://suzukimarine.com/sr_07/df140/features/

Operating Range rpm:5600-6200

[Tris]

thanks could be propped wrong then?

[FrenchPhil]

We'd need more info on his setup - prop, motor height...

[Tris]

from what I could make out on the prop (boat in water) its a 19pitch propom a 140 4stroke suzuki fitted to a 7m ring rib

[Frenchbruno]

your gear ratio is 2.59
Your max actual rpm is 5500
try a prop slip at 10% but I guess yours is far more than this
your 7.00M rib seems underpowered
now use this calculator
http://go-fast.com/Prop_Slip_Calculator.htm
your theorical speed at 10% slip should be 38mph
your real speed at 10% should be 34mph.
Changing propeller to a 17 and hoping 6000rpm doesn't improve the top speed....
May be you have a problem on the engine or engine setup.
34mph on a 7.00 rib is pretty slow even with 140hp.
May be the rib is heavy built.