1989 125hp, what is a safe full load cruising RPM?

I'm told my 125 Force has a 5500 rpm redline, so I'm wondering whats the best RPM to cruise out to where I like to fish, 9 miles out?
20' Open bow Arriva, stripped out for fishing.

Re: 1989 125hp, what is a safe full load cruising RPM?

5500 is NOT a redline! The manufacturer lists the acceptable operating range at WOT as 4500-5500. These engines can easily exceed the 5500 upper limit with no damage. However, horsepower is rated at (I think) 5000 or 5250. Power developed outside this RPM will usually be less than advertised. SO: The MAX RPM you would want at cruise is right at the RPM at which horsepower is rated.

At any rate, 5000 being right in the middle of the listed operating range is a good number to prop for.

Cruising at less than WOT will conserve fuel and about 3/4 throttle is a relatively good place to be. This will deliver different speeds and RPM on different hulls and with different loads.

If you are not sure, look at the throttle cam on the lower carb. Timing advances almost all the way before the throttle is fully opened Cruise is that spot where the "finger" on the cam is not pressing the roller on the carb. This is usually about 1/4 of the carb opening. That last bit of control handle opens the carbs all the way. The engine makes a lot more noise and uses a lot more fuel, but top speed will only increase a couple of MPH.

Re: 1989 125hp, what is a safe full load cruising RPM?



First is full throttle, second is cruise, and third is idle. Note that it was cold and stiff so cruise is not quite to its limit, but close enough for the photos and demo. --you get the idea.

Re: 1989 125hp, what is a safe full load cruising RPM?

On my 19' 1988 Bayliner Cobra open bow, 1988 125 HP motor, I usually cruise around 4000 RPM when I'm on my way to our favorite spot. It's about 25 miles one way.

When pulling skiers or a tube and I've had it up to 6000 RPM on occasion for short periods (less than 30 sec.) with no problems.

Re: 1989 125hp, what is a safe full load cruising RPM?

Frank Acampora said:

If you are not sure, look at the throttle cam on the lower carb. Timing advances almost all the way before the throttle is fully opened Cruise is that spot where the "finger" on the cam is not pressing the roller on the carb. This is usually about 1/4 of the carb opening. That last bit of control handle opens the carbs all the way. The engine makes a lot more noise and uses a lot more fuel, but top speed will only increase a couple of MPH.

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Thanks Frank, this is exactly what I was looking for.