Hard facts about lightened flywheels

[us1]

The Mercury flywheel is balanced just to itself.

[CUDA]

yes, the lightweight flywheel must be balanced with the rotating mass.

wrong!

[us1]

Everything rotating is balanced separately. So no it does not throw it off balance.

So all these guys buying used flywheel or just buying a flywheel and slapping it on their motor are throwing off the balance?

[Classic18]

So all these guys buying used flywheel or just buying a flywheel and slapping it on their motor are throwing off the balance?

Assuming you rotate the entire rotating assembly (which is best), If you replace the flywheel and don't rebalance the recip mass, it will throw off your balance.....unless its the same mass & location. If the mass is very low, should not have an effect

[Mr. Demeanor]

But, if you've had your entire rotating assembly balanced you probably should not swap flywheels. Thats the problem I ran into when mine grenaded but I have no choice but to throw a stock one on.

[Classic18]

Everything rotating is balanced separately. So no it does not throw it off balance.

I don't follow....if you add an extra bolt and nut to your flywheel, you will feel an imbalance....I would guess if the rotating assembly was balanced without a flywheel and the flywheel was on a neutral axis, no effect, but if its imbalanced, it would shake.

[Classic18]

But, if you've had your entire rotating assembly balanced you probably should not swap flywheels. Thats the problem I ran into when mine grenaded but I have no choice but to throw a stock one on.

I agree.....it can be a big b\deal, maybe not.....depends on the added mass...

[us1]

Exactly, That's why Mercury doesn't do it. The parts have to be interchangeable.

But, if you've had your entire rotating assembly balanced you probably should not swap flywheels. Thats the problem I ran into when mine grenaded but I have no choice but to throw a stock one on.

[FMP]

What you do with the recip depends on the configuration of the engine and how it's mounted. The rotating big end rod balanced with the flywheel balanced with or on it's own the flywheel will be the same. A balanced wheel is a balanced wheel. Merc

[CUDA]

This is Quality, less than 4lbs. approved for use in ODBA/DSRA/F1

[Mr. Demeanor]

Wish I could get something that pretty for my Yamaha without spending a fortune for a one off piece.

[us1]

That's exactly right.

What you do with the recip depends on the configuration of the engine and how it's mounted. The rotating big end rod balanced with the flywheel balanced with or on it's own the flywheel will be the same. A balanced wheel is a balanced wheel. Merc

[CUDA]

It's $1,000. when in stock

Nothing good is cheap

Nothing cheap is good .

[rude tim]

The only benifit to a lightened flywheel is crank flex. Dyno test will not show how a boat will perform on the water. Yes a lightened flywheel will spin up faster but the lost mass will allow the engine to dip farther when the prop loads. The real test would be in the water over a measured distance.

[Capt.Insane-o]

Unless he is drag racing this donzi with a data logger the difference between a light flywheel and a stocker is inconsequential. Flyweight stuff is great in a rig that is launched wave top to wave top with nasty rpm spikes. With 1.50 gears and 400 hp he is going to be up there in prop pitch and the heavy bite of a high pitch mirage bravo hydromotive or otherwise will negate much of a spendy flywheel. And it sucks to look like an ass around the docks.