Mrecruiser 3 litre 270HP -low on power, high on fuel

[Nigel52]

I have a QS905WE with Mercruiser 3 litre 270HP inboard and since new top speed has never better 24 knots and at 20knot cruising speed using 55 litres/hr. When googling this below is what I get; hugely different. On the Facebook Quicksilver group others with the QS855 (same hull) and the older VW 260HP engine they are saying 30Knots top speed and 37 litres at 20 knots. (if only)

Anyone have any suggestions how I determine if something is wrong?


The Quicksilver Activ 905 Weekend (QS905WE) with a 270HP inboard engine is a versatile and powerful boat. Here are some key details:

Top Speed​

• The top speed of the Quicksilver Activ 905 Weekend with a 270HP inboard engine is approximately 30-35 knots1.

Fuel Consumption​

• At cruising speed (around 20 knots), the fuel consumption is roughly 30-35 liters per hour2. This can vary based on load, weather conditions, and how the boat is operated.

 

[Keith-i]

Are you reaching correct rpm? Is it correctly propped?

 

[Nigel52]

Are you reaching correct rpm? Is it correctly propped?

Came with standard duo prop which I have not changed. I need to check the rpms next time I am out as currently out for mid-season scrub and new anodes. What rpm at a given speed should i be getting.

 

[Keith-i]

It should reach the maximum rated rpm at full throttle. If not then it is over-propped. If it gets to top rpm before the throttle is on the stops then it’s under propped.

 

[Nigel52]

It should reach the maximum rated rpm at full throttle. If not then it is over-propped. If it gets to top rpm before the throttle is on the stops then it’s under propped.

Thanks, I need to do some checking