Pro's & con's of hp bump with re-power

[boatbod]

I'm guessing we're talking about a 4LH engine since the 4BY didn't come out until 2006 or so. At least it is mechanical vs the BY fully electronic. Solid piece of iron, but very unrefined & prone to being rather smokey.

[jamhass]

Is the shaft large enough for the power? If not, also need new shaft, shaft seals, cutless, etc etc.

And an answer like "no need, won't really ever use the additional power" works right up until the throttle is firewalled the first time and the shaft twists off ...

[FionaJC]

Cadence, I looked it up;

Long ton,[1] also known as the imperial ton or displacement ton[1][2] is the name for the unit called the "ton" in the avoirdupois or Imperial system of measurements standardised in the thirteenth century that is used in the United Kingdom and several other British Commonwealth of Nations countries alongside the mass-based metric ton invented in 1799.

A long ton is defined as exactly 2,240 pounds. The long ton arises from the traditional British measurement system: A long ton is 20 cwt, each of which is 8 stone (1 stone = 14 pounds). Thus a long ton is 20 × 8 × 14 lb = 2,240 lb..
Mine is 6.5 imperial tons

[Cadence]

Originally Posted by FionaJC

Cadence, I looked it up;

Long ton,[1] also known as the imperial ton or displacement ton[1][2] is the name for the unit called the "ton" in the avoirdupois or Imperial system of measurements standardised in the thirteenth century that is used in the United Kingdom and several other British Commonwealth of Nations countries alongside the mass-based metric ton invented in 1799.

A long ton is defined as exactly 2,240 pounds. The long ton arises from the traditional British measurement system: A long ton is 20 cwt, each of which is 8 stone (1 stone = 14 pounds). Thus a long ton is 20 × 8 × 14 lb = 2,240 lb..
Mine is 6.5 imperial tons

I forgot the thanks!

[dmalcol1]

I re-powered 28000lb 40 foot cutter and looked at Nanni and Bata engines I went from 36hp Volvo to 40hp Nanni normally aspirated engine. During my search for new engine it was found that if I wished to use same prop, shaft and TRANSMISSION 40hp was the max and at that the Bata marine 40hp had to much torque. In the end new engine and completely new exhaust was necessary. Kept the expensive parts tranny shaft prop cutlass and stern tub replaced stuffing box to drip-less (mistake dripless bellows failed inside of one year they don't like diesel).