No info...no ideas...HELP

[poppasmurff]

Hoping some one can help me...I just bought a used boat and have been finding some alarming stuff...First...it's a1986 30' Imperial Travel All with a 4.3 v6 that says 205 Hp Mercuiser, and a three bladed 17 pitch prop...it leaves me with WOT of 5100 RPM and about 26 miles and hour...but outta the hole is almost instant...any one know roughly the correct pitch prop that is supposed to be on this poor beast?

 

[Bondo]

Re: No info...no ideas...HELP

Ayuh,.... You should shoot for 4800rpms,... A 19" or a 21" pitch will do it for you...

 

[steelespike]

Re: No info...no ideas...HELP

Did you mean 20 footer? It seems to me a 30 footer with 205 hp would be pretty happy with a 17. And hole shot would be fair to good not instant.
If its a 20 footer I think a 19 would put you at about 4,700.And still leave you with a good hole sahot.

 

[poppasmurff]

Re: No info...no ideas...HELP

It is a 30 footer of that I am sure and it has a 17pitch on it that lets the engine rev at 5200rpm. Thanks for the info, I will look into a 19pitch and maybe a 21pitch just to try them out.

 

[steelespike]

Re: No info...no ideas...HELP

I think I would check the tach first before buying more props.
I have to wonder if the prop is not a diff. pitch less than 17 perhaps reworked, I'm just thinking if its reworked you may end up jumping several inches going to a 19.Of course if you can do a try and buy thats different.
There are plenty of 19 or 20 footers with 4.3 that don't have instant hole shot.

 

[hwsiii]

Re: No info...no ideas...HELP

Smurff, at the very minimum you have a prop slip of 30% using those numbers. So either your tach is wrong or you have the wrong prop, but if you have the wrong prop then your hole shot shouldn't be so quick. So I would say we need more information.


H

 

[poppasmurff]

Re: No info...no ideas...HELP

ok have been asking around and have been told that a 19 pitch 4 bladed is what these came with. the 3 bladed prop would work in a pinch.

 

[hwsiii]

Re: No info...no ideas...HELP

Smurf, if you will answer these questions I will see what help I an give 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 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 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

 

[poppasmurff]

Re: No info...no ideas...HELP

. Year, make and model of boat=1986 ASI Imperial
2. Length, width and base weight of boat, look for boat decal on back of boat=30'long, 8'wide,
2a.What is the recommended HP for your boat=190 to 205 (has a merc V6 4.3)
3. Number of people and gallons of gas normally on boat=50gallons,5 people
4. What do you use the boat for=cruising
5. Is it a Deep Vee and if so how many degrees of deadrise=UNK
6. Year, make. manufacturer and model of motor=1986 4.3 V6 Mercuiser
7. HP and gear ratio of motor IMPORTANT=205
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=informed by marina that gear ratio is 1.72-1
8. Manufacturer?s recommended Wide Open Throttle (WOT) range=unknown, was told ,about 3900-4200RPM
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= huh?
11. Does it have a hydrafoil, dolefin or trim tabs=yes hydrafoil
12. Make, model, diameter, pitch and whether SS or aluminum prop=unsure,unsure,14inch,17
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=WOT RPM is 5500, speed is 27 MPH (by the dash guage)
14. Are you at sea level or a higher elevation, give us the elevation in feet=about 100-320ft
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=tune up recenty
16. How long has this prop been on the boat and why, at this time, do you think it is the wrong prop=been on boat for 2 weeks because last one stolen
17. Does the prop show any damage that you can see=no
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=excesivly high RPMS, low top end,fast out of the hole
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.

 

[hwsiii]

Re: No info...no ideas...HELP

Smurff, I show you have a prop slip of 47% at this time and that is horrible. I also show you should be able to do at least 35 MPH with that setup with the right prop. Just be sure that you know these RPM are RIGHT. hek them with a mehanis tah while you are running WOT and make sure of the RPM.
With that being said, if the RPM are orret then you need to purhase a Solas Amita 4 blade prop with a 19" pith. It will help keep your hole shot good beause of the 4th blade and derease your prop slip tremendously to give you more speed at all RPM.

Prop Slip

H

 

[poppasmurff]

Re: No info...no ideas...HELP

Thank you for the info...sorry so long in replying... ok bought a 4 bladed 19pitch.....works like a champ!!! 32 on the dash board at 4650 RPM!!!