'99 FW Horizon 170 Performance

[jkimball]

Not sure if I landed in the right forum or not, but I have a performance related question I?m hoping to get some help with.

My boat is a 1999 Horizon 170, with the Johnson 115 OB.

I did a decarb on it and changed the spark-plugs in it Saturday and took it out that afternoon. I did notice a huge difference in responsiveness and pickup.

With two 200 lb. adults, a full fuel tank (24 Gal.) and two small children about 85 lbs. combined, I was turning approximately 5000 RPMS at WOT and by GPS 38-40 MPH.

My current prop is the factory OMC 14x19. I DO have a Stingray Starfire Hydrofoil on it as well.

Is this in line with acceptable or expected performance from this boat/ motor Combo? I have searched around and have found very little to answer this. I?m just trying to establish a baseline to gauge expectations & improvements from.

I've had the boat a little over a month, and still learning a little about the Four Winns brand. I know they're built mostly for comfort and cruising, not strictly speed, but it would be nice to have a little of both. Which, IMHO 40 MPH doesn't seem... too bad... or am I setting my expectations too low?

 

[Mischief Managed]

Re: '99 FW Horizon 170 Performance

I know that my buddy's 2000 FW Horizon 170 will hit 41-42 MPH on GPS with a Johnson 90 and two on board. He has a 3 blade SS prop, not sure of diameter or pitch though. Assuming the 99 is basically the same boat, I would think it should hit 47 MPH, if propped correctly.

 

[Slip Away]

Re: '99 FW Horizon 170 Performance

My boat is a 1999 Horizon 170, with the Johnson 115 OB.


With two 200 lb. adults, a full fuel tank (24 Gal.) and two small children about 85 lbs. combined, I was turning approximately 5000 RPMS at WOT and by GPS 38-40 MPH.

My current prop is the factory OMC 14x19. I DO have a Stingray Starfire Hydrofoil on it as well.

Is this in line with acceptable or expected performance from this boat/ motor Combo? I have searched around and have found very little to answer this. I?m just trying to establish a baseline to gauge expectations & improvements from.

IMHO 40 MPH doesn't seem... too bad... or am I setting my expectations too low?

Here are the numbers for your boat and motor from the FW website.
@ 5,000 RPM speed is 41 mph.
Top Speed at WOT is 43-46 mph.

 

[JB]

Re: '99 FW Horizon 170 Performance

Howdy, JKimball.

:welcome:

I suggest an 18" prop. You need another 500rpm at WOT.

 

[jkimball]

Re: '99 FW Horizon 170 Performance

Howdy, JKimball.

:welcome:

I suggest an 18" prop. You need another 500rpm at WOT.

Thanks for the warm welcome and the help. I'm new to propping and all that comes with it, if I do drop the pitch, it will increase my WOT RPMs right?
However, due to the smaller pitch, wouldn't I lose some on top end (but be faster out of the hole)? If I understand it correctly.
I've also heard that going with an equiv. sized SST prop would equate to droping 1 - 2" of pitch as far as RPMs are concerned, is this true?

Trying to figure it all out. We have prop shops around, but not sure if they allow test runs or not? So I'll probably buy online too, as it's cheaper. Just want to make sure I get it right (or as close to as possible) the first time around.

Any thoughts?

 

[Mischief Managed]

Re: '99 FW Horizon 170 Performance

I would verify the engine is in a good state of tune before you do anything with the prop. I know you put fresh plugs in it and such, but it might have a problem if it's only getting to 5k and 40 MPH. Also, did you trim the motor for best speed?