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buffalo716

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trying to prepare before the summer boating season, i decided to buy a couple of used props off the internet for my 89 baja 190, mercruiser v6 260hp i/o, alpha 1 gen 1 (not sure of the gear ratio)....i bought and paid for: a quicksilver mirage ss #48 13704 a41 23p and a quicksilver ss 48 16318 21 21p, are these going to work on my alpha one? or did i buy props that wont work on my outdrive? i have no clue what the #s mean, and im hoping i didnt buy heavy, expensive sinkers! i appreciate any help, thanks! :)
 
I inserted your data into a prop finder spread sheet. I used 3000 lb. loaded weight w/1.81 OD gear ratio. A V-6 260 HP at 4800 RPM calls for a 25 pitch prop. This program is just used for getting in the ballpark. You'll have to give them a trial to see if they will be w/in the engine's RPM range. If you have different data let me know and I'll rerun the data.
 
buffalo716 said:
trying to prepare before the summer boating season, i decided to buy a couple of used props off the internet for my 89 baja 190, mercruiser v6 260hp i/o, alpha 1 gen 1 (not sure of the gear ratio)....i bought and paid for: a quicksilver mirage ss #48 13704 a41 23p and a quicksilver ss 48 16318 21 21p, are these going to work on my alpha one? or did i buy props that wont work on my outdrive? i have no clue what the #s mean, and im hoping i didnt buy heavy, expensive sinkers! i appreciate any help, thanks! :)
Click to expand...

Ayuh,.... Welcome Aboard,... What's yer rpms at Wot with the prop that's on the boat now,..??
What's the Pitch of that prop..??

If the rpms are in Spec,...
'n If the props pitch is a 21" or a 23", you mighta bought the right pitch props....
 
guyjg said:
I inserted your data into a prop finder spread sheet. I used 3000 lb. loaded weight w/1.81 OD gear ratio. A V-6 260 HP at 4800 RPM calls for a 25 pitch prop. This program is just used for getting in the ballpark. You'll have to give them a trial to see if they will be w/in the engine's RPM range. If you have different data let me know and I'll rerun the data.
Click to expand...

Ayuh,.... I'm doubtin' the stated horsepower,.... MPI is only 220hp...
 
I ran it again using a 1.47 gear ratio that matches the 260 HP and it shows a 19 pitch is required. As Bondo stated the WOT range is needed along w/the loaded weight to get an accurate pitch. Also include the OD gear ratio.
 
buffalo716 said:
trying to prepare before the summer boating season, i decided to buy a couple of used props off the internet for my 89 baja 190, mercruiser v6 260hp i/o, alpha 1 gen 1 (not sure of the gear ratio)....i bought and paid for: a quicksilver mirage ss #48 13704 a41 23p and a quicksilver ss 48 16318 21 21p, are these going to work on my alpha one? or did i buy props that wont work on my outdrive? i have no clue what the #s mean, and im hoping i didnt buy heavy, expensive sinkers! i appreciate any help, thanks! :)
Click to expand...

I('m positive it's 260hp it says so on the mercruiser plate on the block) I currently have a 21p aluminum prop, at wot it goes to 4800 rpm the max rpm is rated at 4600..my real question is are these props intended for an alpha one or a bravo drive? The people I bought them from weren't sure .I assumed they were for an alpha one because I also have another ss prop that began with the #48. Probably a dumb assumption.
 
buffalo716 said:
I('m positive it's 260hp it says so on the mercruiser plate on the block) I currently have a 21p aluminum prop, at wot it goes to 4800 rpm the max rpm is rated at 4600..my real question is are these props intended for an alpha one or a bravo drive? The people I bought them from weren't sure .I assumed they were for an alpha one because I also have another ss prop that began with the #48. Probably a dumb assumption.
Click to expand...

Ayuh,.... Then either you've got a V8, or it Ain't a 260hp...

'n,... I've Never Ever seen a 260hp motor that redlines at 4600 rpms,... 4800 rpms is Expected...

The Alpha drives, 'n the Bravo Is can run the same props...
 
What is important is that the splines are the same and the thrust washer is the correct one for the prop bieng used.

almost all Alpha and bravo and large displacement mercury outboards use the same splined props. Some are designed for specifica applications but any can be used for testing. Some boat configuration I have seen work best with outboard props.

Exception is Bravo II and Bravo III use different props all together.

The way to determine what prop to use is,

at ~ 1/2 tank of gas, you alone, run the boat to wide open throttle and trim the drive out/up until max rpms are reached and no cavitation is occurring.

As long as you are within 4400 to 4800 rpms you are typically running the correct prop pitch.

I forget right now but what ever pitch aluminium you are running you either go up or down (maybe someone can remind me which way to go) one pitch when going to a stainless steel......

so if alum is 19 go to a 21 stainless steel or if I am wrong, then if you are running a 19 alum you would go to a 17 stainless steel

That is about all you need to know.
 
Here's your bottom line.

No matter which propeller you bought, you will not know if it is correct until you perform a WOT RPM test.

In order for a WOT RPM test to be effective:

  • the engine must be in full tune.... this means everything... fuel delivery, ignition timing, etc.
  • the drive ratio must be correct for the engine and altitude.
  • the hull must be clean.
  • the propeller must in near pristine condition.
  • the boat should be loaded as you intend to use it. No cheating here!


Now is when you perform the WOT RPM test using the OEM wot rpm specs.
If you can reach the OEM suggested RPM range, and neither exceed or be below it, then you are likely propped correctly.

If you're going to error, error on the side of being under propped, and you will not risk over-burdening your engine.

Remember that WOT RPM is a test RPM...... not an RPM to be sustained for any duration.


.
 
buffalo716 said:
I('m positive it's 260hp it says so on the mercruiser plate on the block) I currently have a 21p aluminum prop, at wot it goes to 4800 rpm the max rpm is rated at 4600..my real question is are these props intended for an alpha one or a bravo drive? The people I bought them from weren't sure .I assumed they were for an alpha one because I also have another ss prop that began with the #48. Probably a dumb assumption.[/QUOTE
Click to expand...
 
NO the 48 does not specify what the prop is for, it is a mercury part number prefix........

Your motor is a Alpha 1 Gen I engine is a 350 cu inch 260 hp and your outdrive is a 1.50:1 ratio for a 1989 (if the motor is a V8) count the damn spark plug wires.........


The answer is

It appears to be a bravo I prop typically used on big block boats (454's and 502's) but that does not mean it wont work on a alpha I

The 48- number is the prefix number that Mercury has assigned all their propellers since the beginning of time, no matter the type, style, or size. The 137 denotes the older, original Mirage stainless propeller series. The 04 & 05 denotes either a left or right hand rotation propeller in this Mirage series. Even numbers denote right hand rotation usually, odd numbers denote left hand. The A41 denotes the hub type in this propeller style/series. The 23P denotes the inches of pitch of the blades. Theoretical pitch is, the distance that the propeller travels through the water, in one revolution. To determine the propellers overall diameter, measure from the center of the hub, out to one of the blade tips, and multiple by two.

A50 is solid metal.
A41 is rubber
A46 is flo Torque II hub
A56 is flo torque SS hub
A65 is 1 1/4" SS hub
 
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