test prop for running up on trailer

[mrcrsr]

merc had a service bulletin for cutting down an aluminum 13pitch(if i remember correctly) prop to turn a predetermined rpm while in the water sitting on the trailer,excellent for testing,allows you turn the motor up and work on it without the boat moving,does anyone have it or know how much to cut off the diameter?

[Markus]

I used to have that service bulletin. I will check if I can find it over the week-end.

[mrcrsr]

thanks marcus

[Chaz]

Charlie ,
Thats a pretty neat trick ..... :D

Charlie....II

[Jeff_G]

MODIFIED PROPELLER FOR TROUBLE
SHOOTING MAG II/XR4 MODELS
It is possible to make a test propeller by modifying a
standard aluminum propeller to assist in troubleshooting
Mag Il/XR4 models. This modified propeller
allows wide–open–throttle operation while the boat is
stationary in the water and secured to a dock or trailer.
Modification consists of reducing the diameter of
a 48–77340A40 (14” x 13”) propeller to 12 inches.
Any prop repair station can make the modification.


Additional models
MODEL
150 HP
120 HP
90 HP
70 HP

PROP P/N
P685-1
P685-1
P685-1
816704A40

PITCH
17
17
17
13

REDUCED DIA
11” DIA
9-7/8” DIA
9” DIA
9” DIA

RPM
5150-5200 RPM
5200 RPM
5000-5150 RPM
5000 RPM

Sorry the above should be in a graph form going across the page.

[Markus]

Thank's Jeff. That's the one I was thinking about.

[mrcrsr]

anyone have it for a higher horsepower engine, like a 200/225? thanks for all the info!

[Instigator]

Charlie, I've got one from OMC that will work on your motor and we used to use them all the time when I was racing.
It is an actual "test wheel" designed specifically for this purpose.
I don't like the Merc method because a real test wheel loads the motor more evenly and is easier on the lower unit and is not trying to push the boat up the trailer..
It looks funky, almost like an O/B jet adaptor (most people ask me that when I use mine) but you literally can hold the motor at WFO w/the boat at dock and the boat doesn't even move!
You can still find them cheap on e-bay.
I'll loan you mine in exchange for beer.

[mrcrsr]

Charlie, I've got one from OMC that will work on your motor and we used to use them all the time when I was racing.
It is an actual "test wheel" designed specifically for this purpose.
I don't like the Merc method because a real test wheel loads the motor more evenly and is easier on the lower unit and is not trying to push the boat up the trailer..
It looks funky, almost like an O/B jet adaptor (most people ask me that when I use mine) but you literally can hold the motor at WFO w/the boat at dock and the boat doesn't even move!
You can still find them cheap on e-bay.
I'll loan you mine in exchange for beer.schweeet!!:D