2006 BF15A kicker on a 24’ cabin cruiser fuel economy

[straub9@gmail.com]

Hey guys just wondering, my 24’ cabin cruiser has a 15hp honda long leg kicker, i only use it in fresh water, just curious what sort of GPH i can expect out of using it to cruise around the lake instead of my main 5.0L inboard/outboard.

 

[ahicks]

I think a lot of the answer here is going to be regarding throttle setting on the kicker. It's not going to use much at anything under half throttle or so. I can tell you that for sure!

 

[km1125]

At full throttle and rated RPM that engine is going to consume 1.2-1.5 gallons per hour. You'd want to use a high-thrust prop to get the engine up in RPMs to take the most advantage of the motor, but it's not going to push the boat anywhere past hull speed which is probably around 6-8MPH.

 

[dingbat]

The only thing you save is the difference in combustion efficiency between the two power sources.

If your dealing with a carburetored 2 stroke you might actually consume more fuel.

 

[MattFL]

The Honda is a 4-stroke, and Honda's are typically excellent on fuel. I would be $1 that the kicker at half throttle is going to use less fuel than the big motor idling in gear.

 

[km1125]

The Honda is a 4-stroke, and Honda's are typically excellent on fuel. I would be $1 that the kicker at half throttle is going to use less fuel than the big motor idling in gear.

I would not bet against you, because that would be a losing bet.

At a similar power output, you've only got the friction of two cylinders on the Honda, vs eight on the inboard. Plus, the inboard is going to be idling, needing to create 13-15 inches of vacuum in the manifold which takes some power to do, while the Honda is going to be nearly at WOT with -at most- a couple inches of vacuum. Also, with the vacuum in the intake, the cylinders don't get a full 'charge' so the effective compression ratio is reduced, which makes an engine less efficient.

The Honda would be definitely more efficient.

 

[ahicks]

And nobody is saying you have to maintain hull speed. Sometimes enough to keep directional stability (2-4 mph) is plenty for "cruising". When I'm "cruising" there's generally no schedule and many times not even a destination....