NEED PROP ADVICE: '78 Johnson115 2stroke/ '82 Ranger 330V

P

phx5kegsman

Petty Officer 3rd Class
Joined
Apr 10, 2021
Messages
94
Hello,
I want to upgrade to a stainless prop. Currently running a stock aluminum 13 x 19. Hole shot is decent, but I suspect that might be from the hydrofoil (on it when I bought it). I run 42mph at 5200 rpm, with a little bit of throttle left to hit WOT. Not sure what my max rpm's are. I'm looking to get better performance and speed. Any suggestions?
Thanks!
 
A

airshot

Vice Admiral
Joined
Jul 22, 2008
Messages
5,574
My suggestion is to get all the facts in order, or your just guessing. Need that max rpm at wot and also what is the max wot rpm rating on the motor !
Be careful with that fin, while they can help, they are also known to break cav plates on out boards when in excess of 40 mph. How much are you willing to gamble for a couple more mph ??
 
jimmbo

jimmbo

Supreme Mariner
Joined
May 24, 2004
Messages
13,781
4500-5500rpm is the WOT Range
As mentioned Above, 42mph at 5200 with a bit more Throttle is Meaningless. You/we Need to know what it actually is at WOT.
Is the motor in good Mechanical Shape? Compression numbers, please
Is the Spark properly advance at WOT?
Are the Carbs fully open at WOT?
Is the Engine mounted on the Transom at the Correct Height?
Is the engine Properly trimmed at WOT?

Myself I would remove the Hydrofoil and see how far from the boat I could throw it.

As for the Stainless, unless you are choosing a Stainless Prop that is designed as a Performance Prop, instead of just an SS version of an AL Prop, you aren't going to see any significant changes in Speed. Be aware that any Impact when running a SS, can result in more Damage to the Drive Train than with an AL Prop.
 
C

cyclops222

Commander
Joined
Mar 21, 2024
Messages
2,397
GPS mph ? Is the tachometer accurate when compared to a accurate one ?
How did the person who installed it KNOW where to mount it for a loaded boat ?
WOT what happens to the bow angle. As you trim the motor ? ?
 
Last edited:
A

airshot

Vice Admiral
Joined
Jul 22, 2008
Messages
5,574
jimmbo said:
4500-5500rpm is the WOT Range
As mentioned Above, 42mph at 5200 with a bit more Throttle is Meaningless. You/we Need to know what it actually is at WOT.
Is the motor in good Mechanical Shape? Compression numbers, please
Is the Spark properly advance at WOT?
Are the Carbs fully open at WOT?
Is the Engine mounted on the Transom at the Correct Height?
Is the engine Properly trimmed at WOT?

Myself I would remove the Hydrofoil a
Click to expand...

jimmbo said:
4500-5500rpm is the WOT Range
As mentioned Above, 42mph at 5200 with a bit more Throttle is Meaningless. You/we Need to know what it actually is at WOT.
Is the motor in good Mechanical Shape? Compression numbers, please
Is the Spark properly advance at WOT?
Are the Carbs fully open at WOT?
Is the Engine mounted on the Transom at the Correct Height?
Is the engine Properly trimmed at WOT?

Myself I would remove the Hydrofoil and see how far from the boat I could throw it.

As for the Stainless, unless you are choosing a Stainless Prop that is designed as a Performance Prop, instead of just an SS version of an AL Prop, you aren't going to see any significant changes in Speed. Be aware that any Impact when running a SS, can result in more Damage to the Drive Train than with an AL Prop.
Click to expand...
A " hydro frisbie". Wish I would have thought if that !
 
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