Fan, welcome to Iboats prop forum and I will try to help you as much as I can but without more information no one can help you, and I will tell you I need more information than anyone else. But if you would like my help fill this form out and I will help you as much as I can.
I ran some preliminary numbers, and if your gear ratio is 1.83:1 I found you prop slip is 24%, and that is way too much.
You might try reading this for a better understanding of motor height, changing props for better performance, and for the major differences between aluminum props and stainless steel.
http://forums.iboats.com/showthread.php?t=369057
If you would prefer to not go to this much trouble there are many other people who will come along and gladly help you.
1. Year, make and model of boat
2010 ALumacraft Classic 165 CS
2. Length, width and base weight of boat, look for boat decal on back of boat
16'5", 83" beam, 890lbs dry weight
2a.What is the maximum recommended HP for your boat
75
3. Number of people and gallons of gas normally on boat and what do you use the boat for
3 people, at least 15 gallons, used strictly for fishing.
4. Year, make. manufacturer and model of motor and recommended Wide Open Throttle (WOT) range
2010 Merc 60hp EFI fourstroke (non big foot). 5500 to 6000 RPM recommended operation range
5.
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 then do the same thing on the flywheel and turn the motor until the tape lines up with each other on the prop, it is easier if two people do this, so one can watch the prop while the other counts the revolutions of the motor
60 hp 1.83:1 gear ratio
6. Anti-ventilation Plate height above keel of boat if it is an outboard in inches, use a straight edge under the keel and sticking out to the anti ventilation plate for a reference
Motor Transom Height This I am not sure
When the boat is running in the top 20% of your speed you should be able to see the anti ventilation plate very clearly at the top of the water and have water just splashing over the top of it.
I have checked this in the past and it seems to be ok
Correct Anti Ventilation Height
7. 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. Make sure you trim the prop up until it starts ventilating and then just trim in until it quits ventilating.
RPM ___
5800____ Speed __
30mph via GPS___ GPS ______ No. of people __
3____ Gal. Gas ___
18_____
8. Make, model, diameter, pitch, number of blades and whether SS or aluminum prop and does it have a hydrafoil, dolefin or trim tabs
Standard merc 3 bladed aluminum prop - 10 7/8 x 13 (it is either 10.5 or 10 7/8 I am not at home to check. No hydrofoil or trim tabs, etc.
9. Has your motor been tuned up lately and have you checked that the carburetor butterfly is opening all the way by just pushing the throttle at the helm and not at the carburetor, checked compression, and looked at the plugs and checked spark as well as timing and advance, all of the foregoing could be the reason your prop is not attaining full RPM
Brand new
10. 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 and does the prop show any damage that you can see
Thought I would see more top end but 30 mph is ok....it struggles at times to get on plane
REMEMBER, The numbers I give you will be NO better than the information you give me. I use a computer program I designed to find the correct pitch and then knowledge to pick a Better prop design for your boat.
The only thing I ask of you is to come back and give me a report of WOT RPM and speed for my database. will do!
H
