Throttle Position vs. RPM.

[bobeast]

Hi All. I just sea trial'ed a 2002 310SA last week with twin 350 MPI/V-drives. I dutifully brought both engines up to 4800 RPM. So far so good.

The odd thing though, is that the throttle levers were only at about half-way through their travel at max rpm. Moving the throttle further made no difference in RPM or sound.

Several things came to mind. Throttle lever calibration? Under-propped? Hitting a very polite rev limiter? I had the survey done and the surveyor verified that moving the levers past the mid point did indeed move the throttle on the TBs.

How should I expect throttle lever position to correlate to max RPM? Seems to me like I shouldn't hit max RPM until the levers were pretty close to the limits of their travel. Somebody please set me straight.

 

[hottoddie]

Throttle assemblies usually have different positions that the cables can be attached to that will result in varying amount of cable movement. Maybe relocating the position they are mounted to would correct the issue. What speed was the boat going at 4800 rpm?

 

[bobeast]

Throttle assemblies usually have different positions that the cables can be attached to that will result in varying amount of cable movement. Maybe relocating the position they are mounted to would correct the issue. What speed was the boat going at 4800 rpm?

Thanks! It never even occurred to me there might be such an adjustment. I'll look into that if the deal goes through.

As for speed, the boat had neither a speedometer nor a GPS. It never even occurred to me to use my phone. Lesson learned. I will say, it seemed to get up on plane without any drama.

 

[Air O'Nautical]

I’d setrial again and see the speed on a hand held GPS/phone.
You want to know if it’s performing correctly before you buy.
Re-prop after sale is $$$

 

[bobeast]

I’d setrial again and see the speed on a hand held GPS/phone.
You want to know if it’s performing correctly before you buy.
Re-prop after sale is $$$

Thanks. that's probably great advice. However, it may be a moot point. Survey just came back and there are a couple of bad stringers.

 

[NorCal Boater]

Thanks. that's probably great advice. However, it may be a moot point. Survey just came back and there are a couple of bad stringers.

Ouch....

 

[bobeast]

Ouch....

Does your screen name mean you are a delta rat?

If so id like to pick your brain about local marinas.

 

[NorCal Boater]

Does your screen name mean you are a delta rat?

If so id like to pick your brain about local marinas.

I was a Delta Rat for over 10 years until last year when I retired and moved to the New Orleans area. Weak and abused brain cells have somewhat diminished the brain but you are welcome to pick away. Send me a private message and I will get back as soon as I can.

Shawn