Ouch and ouch

[oshkoshboating]

Enjoying a nice day of boating and of course I have to hit something with the propeller. It's REALLY messed up (attached a picture for your grim pleasure), but the boat suffered no damage at all, so I got lucky in that aspect. I was able to drive it back without any vibration or listing issues - just a big drop in speed.

The numbers on the propeller are as follows: 23n1 48 78120 A40 19P

Besides 19p (which I assume is 19pitch), what do the other numbers indicate?

Next, the fin(?) on the lower unit also hit the same object (attachment #2 & #3). Is it bad enough that I need to replace it? And if yes, anyone care to throw out an average labor cost? (Mercuriser Alpha one outdrive, Mercruiser 180HP MCM 180 3.7L motor).

Thanks.

 

[Silvertip]

Re: Ouch and ouch

The other numbers are the specific part number for that prop. They mean nothing other than identifying the prop to the parts department. As for the fin on the lower unit, smooth it out with a file or grinder and go boating. You won't notice any difference.

 

[hwsiii]

Re: Ouch and ouch

The numbers indiate you have a 14" diameter with a 19" pith Blak Max prop by Merury and the first 4 numbers are the vesion number if I remember orretly.


H

 

[oshkoshboating]

Re: Ouch and ouch

How did you get a 14" diameter from that?

hwsiii, when you have time, can you run my numbers to see if I have the right prop? Danke!

1. Year, make and model of boat
1987 Larson I19 Citation Bowrider

2. Length, width and base weight of boat, look for boat decal on back of boat
Gunnel Length = 20' 2"
Length = 18' 8"
Beam = 90"
Approx weight = 2250 lbs
Max weight capacity - 1865 lbs
Maximum people = 12

2a.What is the recommended HP for your boat
Where would I find that out

3. Number of people and gallons of gas normally on boat
3 people & gear (720lbs) + full tank (27gal)

4. What do you use the boat for
Cruising

5. Is it a Deep Vee and if so how many degrees of deadrise
Yes, and I don't know.

6. Year, make and model of motor
1987 Mercruiser
Model = MCM 180
Displacement = 224 cid - 3.7L

7. HP and gear ratio of motor IMPORTANT
180 HP & I can't find it on the link. Here are the serial #'s:
Outboard = Mercuriser Alpha One
Serial # = 08620744

Drive Unit
Mercruiser
Serial # 0b611415

8. Manufacturer?s recommended Wide Open Throttle (WOT) range
Max WOT RPM = 4400 - 4800

9. Anti-ventilation Plate height above keel of boat if it is an outboard in inches
not an outboard

10. Is it a bass boat or does it have a pad bottom
not a bass boat.

11. Does it have a hydrafoil, dolefin or trim tabs
No

12. Make, model, diameter, pitch and whether SS or aluminum prop
Quoting you "...14" diameter with a 19" pith Blak Max prop by Merury and the first 4 numbers are the vesion number..."

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.

I leave it at 4000 RPM - anything about it and the motor begins to sound like it is being overworked (4000 is the end of the blue band on the TACH). Gunning it to 4000 RPM gets me planed up in about 4-6 seconds.

I can reach 35-37MPG with the above mentioned people, gear, and gas. That is per GPS.

14. Are you at sea level or a higher elevation, give us the elevation in feet
746 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 forgoing could be the reason your prop is not attaining full RPM
Tuned up in the spring. Motor runs fine until I go above 4000RPM (which starts into the yellow zone on the tach)

16. How long has this prop been on the boat and why, at this time, do you think it is the wrong prop
Not sure - bought the boat with the prop a month or so ago. It could be the right prop - but its busted up so I wanted to verify I had the correct prop.

17. Does the prop show any damage that you can see
Oh yeah! All info above is pre-damage.

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.
See #16.

Thanks.

 

[hwsiii]

Re: Ouch and ouch

Osh, these numbers tell me it is a 14 x19 prop, 48 78120.

And I will be more than happy to run your numbers.


H

 

[Kymasabe]

Re: Ouch and ouch

Regarding the fin on the bottom, the skeg. You can buy a SkegGuard in stainless steel to go right over the existing skeg or another company called BlackFin Skegs will also install over your existing skeg...if it really bothers you. With less and less skeg, you may see a steering difference at low speeds but for now you have plenty of skeg left. I'd file/grind it a little to make it pretty and leave it alone.

 

[oshkoshboating]

Re: Ouch and ouch

Hwsiii - just curious on how you found 14" diameter in that ramble of numbers.

Kymasabe - thanks for the info! I will check into that.

 

[hwsiii]

Re: Ouch and ouch

I have a merury database for props and I just lookup the numbers. I don't have them all by any means, but I have a lot of them. LOL


H

 

[rs1lollie]

Re: Ouch and ouch

You can also turn it into your insurance company if you have insurance and a low deductible.

 

[oshkoshboating]

Re: Ouch and ouch

I have a merury database for props and I just lookup the numbers. I don't have them all by any means, but I have a lot of them. LOL


H

Gotcha!

 

[hwsiii]

Re: Ouch and ouch

Osh, the only question I have is about your RPM, I don't understand why it won't run over 4,000 RPM without sounding like it is over revving. I find it should be turning 4,600 RPM at WOT and has a gear ratio of 1.7:1, please verify this by alling your nearest dealer.
I show you ould possibly turn a higher pith than you have right now, but your prop slip is rather high at 15% for having 1 HP for every 17 pounds of weight.
Please explain why you think it is over revving above 4,000 RPM, and if it is then you need to run a mehanis tah while you are out and see what WOT RPM and speed really are.
If there is a swith on the bak of the tah try turning it a few times to lean the ontats and see if it shows you any different numbers.

H

 

[oshkoshboating]

Re: Ouch and ouch

You can also turn it into your insurance company if you have insurance and a low deductible.

Why yes, yes I do!

My wife brought that up also. Checking into it tomorrow.

 

[oshkoshboating]

Re: Ouch and ouch

Osh, the only question I have is about your RPM, I don't understand why it won't run over 4,000 RPM without sounding like it is over revving. I find it should be turning 4,600 RPM at WOT and has a gear ratio of 1.7:1, please verify this by calling your nearest dealer.
I show you ould possibly turn a higher pith than you have right now, but your prop slip is rather high at 15% for having 1 HP for every 17 pounds of weight.
Please explain why you think it is over revving above 4,000 RPM, and if it is then you need to run a mehanis tah while you are out and see what WOT RPM and speed really are.


H

When I throttle it down past 4kRPM, the engine just starts to run like crap. It doesn't over rev - it starts to run hard and rough sounding.

"run a mehanis tah" - not sure what you mean by mehanis tah.

 

[hwsiii]

Re: Ouch and ouch

My doesnt work, tahometer.
That means that something is wrong with the motor and it needs to be fixed, to be able to get the right prop.

H

 

[oshkoshboating]

Re: Ouch and ouch

I also figured it (motor) wasn't 100%, but I was going to get it looked at later at the end of the season. We were okay with running at 4k @ 35-37mph, and the motor purrs up to 4k (and starts on first crank).

Do you know how fast it should be going with proper RPM & prop pitch? 40-42?

 

[oshkoshboating]

Re: Ouch and ouch

Or maybe my tach is off?

 

[hwsiii]

Re: Ouch and ouch

In my opinion you should be getting in the low 40's, and if you want to go ahead and get a prop now I would reommend a Solas Amita 4 blade aluminum prop in a 19" pith. Quite frankly I reommend this prop on a regular basis, beause it is very easy to turn for a 4 blade prop and with the 4th blade it always brings the prop slip down, whether the boat is heavy or light beause it piks more than just the stern of a boat up very well and thus gives good speed inreases. It is not always the best prop for a boat but when you want a prop that will almost always improve performane and have better handling and ride harateristis it is superb for the prie.


H

 

[hwsiii]

Re: Ouch and ouch

That is why I said use a shop tahometer. LOL mehani

My "c" key is not working, I have ordered a new keyboard.

H

 

[oshkoshboating]

Re: Ouch and ouch

So a 20 or 21P blade won't do me any good (you mentioned above a higher pitched prop might be better)?

 

[oshkoshboating]

Re: Ouch and ouch

LOL! no problem - I am "slow on the uptake" tonight also.