Propeller Pitch on 40HP

[spartacus]

Hi

Can anyone advise what the propeller pitch is on my 40HP, 2-stroke, 3 cylinder, Autolube engine. Model is: 40VMOL (1995).

The propeller (standard aluminium prop) has 13 splines with 12 G 3 stamped on it. Hub diameter is 3", with blade circumference of 9.75."

Has anyone ever switched to Yamaha performance propeller in stainless steel on this engine - I'd be interested to hear. I know it's relatively common-place on larger engines (90HP+) but would welcome any views on benefits.

Cheers

[boats.net]

Do you know what Rpm's it is turning now the 12 pitch alum prop?

[spartacus]

Hi

No. I've just bought a second-hand Yamaha analogue tacho which I'm in process of wiring up. Engine specification says that WOT is 5,500 revs. This is for standard aluminium propeller.

Cheers

[boats.net]

The operating range is 4500-5500 rpm's and you need to prop it out to within that range.

[spartacus]

I assume it works just fine within that operating range of 4,500 - 5,500 revs. Engine is mint with less than 30 hours from new, even although it's 1995. Was in storage (boxed from new for a number of years). If the prop does top-out within that range - I assume changing to a s/s Yamaha performance 3-blade prop will offer a marginal 3-5mph increase in top-end speed. I've been advised that it's not worth the expense given it's only 40HP. More success in upgrading engine to 50HP.