broken 4 blade comp prop

[66 joe]

I need prop suggestion for 96 wellcraft 190 cc with 112 johnson spl. Orig had a 4 blade composite with no. 04347k. Power head was just rebuilt, and at the lake, motor was shaking bad till it got on plane. Turns out 1 of the 4 blades broke off. I have no idea what the max rpm was. I liked the orig 4 blade comp. would go 40 mph no prob, So just trying to get something similar or better,, , Thanks, Joe

 

[hwsiii]

Re: broken 4 blade comp prop

Joe, I show that with a 4 blade prop running close to maximum RPM of 5,500 RPM and a gear ratio of 2:1, please verify this, that you should be running right at a 17" pitch prop with about a 10% prop slip. Although I am not sure that is true for composite props, you need to find out what pitch you were running and what your RPM were. If it was me I would buy an extra blade for the composite prop and see what RPM it is turning and then switch to an aluminum 4 blade because composite blades break too easily, in my opinion.


H

 

[66 joe]

Re: broken 4 blade comp prop

I cross referenced part no. on my broken and found it to be a 4x12.8x17.
Since this orig came with motor, would it be good idea to stay with same no's? I do like orig performance. of course with alum.

 

[66 joe]

Re: broken 4 blade comp prop

need more coffee this am,,, 4 = blades, 12.8 is diameter right? and 17 is pitch like suggested.

 

[hwsiii]

Re: broken 4 blade comp prop

Yes you are right. Please fill out this form.

Iboats Boat and Motor Info
1. Year, make and model of boat
2. Length, width and base weight of boat, look for boat decal on back of boat
2a.What is the recommended HP for your boat
3. Number of people and gallons of gas normally on boat
4. What do you use the boat for
5. Is it a Deep Vee and if so how many degrees of deadrise
6. Year, make and model of motor
7. HP and gear ratio of motor IMPORTANT
If you don?t know the ratio, you need to pull the plugs out and put a piece of tape across the prop and the lower unit and then cut it between the prop and the housing and turn the motor until the tape lines up with each other, it is easier if two people do this, so one can watch the prop while the other counts the revolutions of the motor
8. Manufacturer?s recommended Wide Open Throttle (WOT) range
9. Anti-ventilation Plate height above keel of boat if it is an outboard in inches
10. Is it a bass boat or does it have a pad bottom
11. Does it have a hydrafoil, dolefin or trim tabs
12. Make, model, diameter, pitch and whether SS or aluminum prop
13. WOT RPM and speed from your current prop and how much gas and how many people were in the boat for the test data and is the speed by GPS. If you do not have a tach you can buy a Tiny Tach for $ 50
14. Are you at sea level or a higher elevation, give us the elevation in feet
15. Has your motor been tuned up lately and have you checked that the carburetor butterfly is opening all the way, checked compression, and looked at the plugs and checked spark, all of the foregoing could be the reason your prop is not attaining full RPM
16. How long has this prop been on the boat and why, at this time, do you think it is the wrong prop
17. Does the prop show any damage that you can see
18. What problems are you trying to cure or what are you looking for the boat to do that it is not doing the way you think it should or to your expectations
19. If you are trying to attain a better cruising speed and fuel savings or trying to attain a faster speed I will want you to take your boat and run it with 1 or 2 people and give me the RPM and speed readings starting at 3,000 RPM in 500 RPM increments all the way to WOT.

REMEMBER, The numbers I give you will be NO better than the information you give me

The only thing I ask of you is to come back and give me a report of WOT RPM and speed for my database.


H

 

[66 joe]

Re: broken 4 blade comp prop

I'll get answers hopefully by this weekend
thank you,,, joe