Hi everyone,
Cool web site for boat owners!!! Especially for the brand specifics!
I could use some assistance with trying to figure out what kind of prop change, with a 2004 Johnson 115 HP 4 Stroke, will improve the performance of my boat and engine. I'm interested in a good compromise of top end speed and decent hole shot, not a primary focus on one or the other.
Because I am still learning I do not know the prop makers out there and their benefits. I'd say I'm not too afraid to buy a decent prop of good quality but with nothing to go on yet, I don't know if that's a $200 prop or a $500 prop (or am I kidding myself on prices?
).
In all my searching I see a lot of minor adjustments needed for most people but my situation appears to be a bit unique.
The problem are:
When I try to take off from a stop or very near stop, my prop ventilates pretty bad. I have to drop out of throttle to get it to hook up and rethrottle at a slow rate to keep it hooked up. I'm guessing if it'd just hook right up it'd come right out of the hole and on plane because it doesn't seem to do too bad now.
Same ventilation problems (blow out?) for pretty sharp turns.
Also the engine hits its rev limiter far too easy. I realize it's subjective but I'm quite a ways from full physical throttle position forward and hitting the rev limiter of the motor (~6300 rpms). Maybe 80% of full throttle physical range and it hits the rev limiter while cruising.
You're probably thinking "Prop Slip", right? Read on...
I've seen it mentioned that prop slip could be the problem but if I interpret correctly a common symptom of prop slip is the prop hooks back up and gains thrust when easing back on the throttle a little when cruising. Mine doesn't, it continues to push right up till the rev limiter starts and I'm doing about 32 mph.
The Antiventilation plate is just about dead even with the bottom of the boat. Maybe down below just a hair (1/4"?).
I have my suspicions the prop is just way too small and the engine has so much torque that it can't grab enough water and ventilates.
I have a 13 1/2 x 15 prop and there's only 1 prop smaller available and it's 13 1/2 x 13. This motor is good for up to a 14" diameter prop, so it looks like I have a decent selection of options.
Now the big question: Anyone in here have a very similar set up that can advise me on what prop is performing satisfactorily on yours? I understand the general rule of 1" pitch increase drops rpms about 200, but I'm so far over max rpms hitting the rev limiter that I can't get an idea on what size and pitch to consider.
The details:
Application: It's used strictly for fishing, not skiing or pulling tubes. Typically carry 1 - 3 people fishing.
Boat - 2004 Lund 17' Angler SS.
Motor: 2004 Johnson 115 HP 4 Stroke.
Prop: 5033322 - 13 1/2" x 15" Perfect shape, no scrapes.
I can't express just how much I appreciate your help on this!!!
Andy
Cool web site for boat owners!!! Especially for the brand specifics!
I could use some assistance with trying to figure out what kind of prop change, with a 2004 Johnson 115 HP 4 Stroke, will improve the performance of my boat and engine. I'm interested in a good compromise of top end speed and decent hole shot, not a primary focus on one or the other.
Because I am still learning I do not know the prop makers out there and their benefits. I'd say I'm not too afraid to buy a decent prop of good quality but with nothing to go on yet, I don't know if that's a $200 prop or a $500 prop (or am I kidding myself on prices?
).In all my searching I see a lot of minor adjustments needed for most people but my situation appears to be a bit unique.
The problem are:
When I try to take off from a stop or very near stop, my prop ventilates pretty bad. I have to drop out of throttle to get it to hook up and rethrottle at a slow rate to keep it hooked up. I'm guessing if it'd just hook right up it'd come right out of the hole and on plane because it doesn't seem to do too bad now.
Same ventilation problems (blow out?) for pretty sharp turns.
Also the engine hits its rev limiter far too easy. I realize it's subjective but I'm quite a ways from full physical throttle position forward and hitting the rev limiter of the motor (~6300 rpms). Maybe 80% of full throttle physical range and it hits the rev limiter while cruising.
You're probably thinking "Prop Slip", right? Read on...
I've seen it mentioned that prop slip could be the problem but if I interpret correctly a common symptom of prop slip is the prop hooks back up and gains thrust when easing back on the throttle a little when cruising. Mine doesn't, it continues to push right up till the rev limiter starts and I'm doing about 32 mph.
The Antiventilation plate is just about dead even with the bottom of the boat. Maybe down below just a hair (1/4"?).
I have my suspicions the prop is just way too small and the engine has so much torque that it can't grab enough water and ventilates.
I have a 13 1/2 x 15 prop and there's only 1 prop smaller available and it's 13 1/2 x 13. This motor is good for up to a 14" diameter prop, so it looks like I have a decent selection of options.
Now the big question: Anyone in here have a very similar set up that can advise me on what prop is performing satisfactorily on yours? I understand the general rule of 1" pitch increase drops rpms about 200, but I'm so far over max rpms hitting the rev limiter that I can't get an idea on what size and pitch to consider.
The details:
Application: It's used strictly for fishing, not skiing or pulling tubes. Typically carry 1 - 3 people fishing.
Boat - 2004 Lund 17' Angler SS.
Motor: 2004 Johnson 115 HP 4 Stroke.
Prop: 5033322 - 13 1/2" x 15" Perfect shape, no scrapes.
I can't express just how much I appreciate your help on this!!!
Andy