boat speed

[ringo111]

hi . i just purchased a 1977 reinell 17 ft boat it is powered by a 2001 honda 75 hp 4 stroke i am only getting 30 mph on a clear day is this a good speed for boat or should it be going faster. motor runs good.thanks

 

[JoLin]

Re: boat speed

30 mph sounds about right to me.

1. Are you measuring speed by GPS? You want to do that, and you can use a portable automotive GPS for that.
2. What is your RPM at WOT (wide open throttle)?
3. What is Honda's recommended WOT rpm range for that motor?

If 2. and 3. match up, you're running right where you should be. If they don't, a prop change (either more or less pitch depending on your actual results) will help a bit.

 

[ringo111]

Re: boat speed

wot is about 2000 rpms,

 

[Silvertip]

Re: boat speed

wot is about 2000 rpms,

Ahhh -- NO! A 75 four stroke won't even be on-plane at 2000 rpm and certainly not 30 MPH at WOT of 2000 rpm. You either misread the tach or your tach is not calibrated correctly.

 

[dingbat]

Re: boat speed

wot is about 2000 rpms,

looking at a very large prop change. That motor should run WOT@5500 rpm

 

[jestor68]

Re: boat speed

Honda WOT range is 5000-6000.

 

[ringo111]

Re: boat speed

thanks .i ran the boat last night in calm water,full throttle speed 25 mph. rpm was between 2000 to 2500 rpm .boat never seem to plane out .motor is running great.

 

[JoLin]

Re: boat speed

thanks .i ran the boat last night in calm water,full throttle speed 25 mph. rpm was between 2000 to 2500 rpm .boat never seem to plane out .motor is running great.

Nope. Something's seriously screwed up. Possibilities. 1. Your tachometer is broken or isn't set to the correct 'pole' for your motor, 2. The motor isn't actually 'running great' at all, 3. You're propped so far out of whack that it'll only reach one third of its rated WOT rpm.

I'd consider # 1 to be the most likely culprit.

 

[ringo111]

Re: boat speed

i will try another run tomorrow .iwill take gps to check speed.

 

[Bondo]

Re: boat speed

i will try another run tomorrow .iwill take gps to check speed.

Ayuh,... Ya need to bring a Shop Tach to verify the rpms,....

I suspect yer tach is Broken...

 

[ringo111]

Re: boat speed

tach is not working properly, still not getting speed ,boys say 75 hp should do 40 to 50 .i am getting 26 mph tops

 

[southkogs]

Re: boat speed

tach is not working properly, still not getting speed ,boys say 75 hp should do 40 to 50 .i am getting 26 mph tops

A 17' with a 75HP getting 50? That seems high to me, but maybe not. I would think that the 30MPH range fits pretty well.

 

[KDAVID1]

Re: boat speed

I doubt 50. Maybe 40 or a bit over. But does sound like Tach , speedo, are all out of sorts.

 

[generator12]

Re: boat speed

If that Reinell is a glass boat, 70 HP is not likely to get it up to 40MPH. 33 or 34 is more like it. If it's aluminum, mid-high 30s would make sense.

 

[saxrulez]

Re: boat speed

Absolutely no way you will get 40mph out of a 75hp engine on a fiberglass boat of that size.

I have 120hp 2 stroke(less weight) and I get 42mph on a 16.5' boat. I could gain a 1-2mph by changing props, but I prefer the hole shot.

This is with 45 more horsepower on a smaller boat.

 

[Bondo]

Re: boat speed

tach is not working properly, still not getting speed ,boys say 75 hp should do 40 to 50 .i am getting 26 mph tops

Ayuh,.... You've been Lied too...

 

[KDAVID1]

Re: boat speed

yep--150xr6 on 18ft Ranger--60 on a very good day--normal 56-58

 

[26aftcab454]

Re: boat speed

Ayuh,.... You've been Lied too...

26 WOT sounds about right. It is what it is!

 

[ringo111]

Re: boat speed

thanks guys.