Newbie w/ a Prob

greeaatoutdoors

greeaatoutdoors

Cadet
Joined
Aug 21, 2009
Messages
14
I'm new to boating, so take it easy on me fellas.

I bought my first boat a couple weeks ago, an '87 Glasstream 172 Cutlass. It's got a 3.0 Mercruiser with the Alpha outdrive. I'm not sure what brand the prop is, or even what size, but I know it has a 17 pitch and is a 3 blade aluminum.

I launched it for the first time Saturday, started fine, engine ran smooth, everything was good until I hit what I'm assuming was some rock, I hadnt even made it out of the no wake zone yet, I was pretty upset. The engine would get up to about 4K RPM and then its like the prop just wouldnt push the boat any faster (I was barely crawling). I took the boat out of the water and the prop is pretty chewed up.

Could this be the reason why my boat wont get up any speed or plane out?

And since I'm pretty sure I need a new prop now, could someone tell me what size I need?
 
Silvertip

Silvertip

Supreme Mariner
Joined
Sep 22, 2003
Messages
28,771
Re: Newbie w/ a Prob

Why call a marine shop? Yes -- a chewed up prop can cause performance issues. But so can a prop that has a spun hub (where the center of the prop spins inside the blade area). You don't want to run with a chewed up prop anyway so why not have it repaired or buy a new one right here on iBoats. They sponsor this forum so why not support them.
 
slasmith1

slasmith1

Lieutenant Junior Grade
Joined
Dec 2, 2008
Messages
1,028
Re: Newbie w/ a Prob

call your local prop shop and have the one you already have rebuilt. you will need a prop to get starting rpm numbers any way to find out what the right prop for your boat is.
 
hwsiii

hwsiii

Commander
Joined
Jan 25, 2009
Messages
2,639
Re: Newbie w/ a Prob

Great, the questions in that thread are as basi as they an be to help you find a better prop for your boat than the one you have. If you aren't willing to spend the time to give people the information they need to help you then just replae what you had on there with the same prop.


H
 
skargo

skargo

Banned
Joined
Sep 14, 2008
Messages
4,640
Re: Newbie w/ a Prob

Someone here has a great list of info needed to answer your question.

I had no luck in my search, if I find it I will certainly point you to it.
 
greeaatoutdoors

greeaatoutdoors

Cadet
Joined
Aug 21, 2009
Messages
14
Re: Newbie w/ a Prob

Thanks guys for all of your help.

1) Performance issue you are trying to correct.
2) Current prop manufacturer, model, aluminum or stainless and as a minimum.
3) Current prop diameter and pitch (required).
4) Wide open throttle RPM and speed with an average load (very helpful)
5) Engine/drive make, model, year, and HP
6) Boat make model, year, length and weight

My main problem is the boat wont get any speed or even try to plane out, but the engine still revs (to about 4000 RPM). I know no one is going to be able to tell me exactly what my problem is, I just want to know if me "boogering" up the prop could lead to this kind of problem, or should I look for problems elsewhere?

I dont know the prop dia (how can I tell?), the pitch is 17" (what the previous owner told me). It's aluminum, 3 blade. Where can I find a part # on the prop?

I dont know the wide open RPM & speed with an average load because I just bought the boat and I cant get it up to any speed with the problem I'm having.

The engine is a I/O 3.0 Mercruiser with an Alpha One outdrive, I think it is 140 HP, but I'm unsure of that as well.

My boat is a 1987 Glasstream 172 Cutlass, 17 ft, I'll have to look into the weight of the boat, the sticker that has that info is no longer on the boat.

If no one can lead me in the right direction with this info, I'll just have to take it to a shop. I'm not experienced when it comes to boats, I'm just trying to learn. Thanks again fellas.
 
hwsiii

hwsiii

Commander
Joined
Jan 25, 2009
Messages
2,639
Re: Newbie w/ a Prob

If you will fill out this form I will be glad to try and help you find a muh better prop than what you have.

Welcome to Iboats prop forum and we will try to help you as much as we 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, if you would prefer to not go to this much trouble there are other people who will gladly help you.

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 maximum 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. manufacturer 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 a c ross 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, use a board under the keel and stiking out to the anti ventilation plate for a referene
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. Make sure you trim the prop up until it starts ventilating and then just trim in until it quits ventilating. 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
 
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