Maxed out Alpha

[Rajobigguy]

I just want to get a feel for how far you've taken your alpha drive and how long of a life you got out of it. I know Mercury rates them for 300 but I've heard that with the additon of a shower, a remote resevoir, and a 4 blade prop that you can run them @ 400+. In the real world is anyone doing this and what kind of boat and operateing conditions do you have?

 

[OCMerrill]

I just want to get a feel for how far you've taken your alpha drive and how long of a life you got out of it. I know Mercury rates them for 300 but I've heard that with the additon of a shower, a remote resevoir, and a 4 blade prop that you can run them @ 400+. In the real world is anyone doing this and what kind of boat and operateing conditions do you have?

The lowers seem fine. I have broke two uppers.

Boat in sig. I think where I fail is turning excessive rpm or hammering them out of the hole on a heavier boat.

Big plus - you can find stuff for them all over ebay. I have done that twice. No drive shower and whats available for an Alpha really doesn't help much.

I was running Torco but this drive is just getting Mercruiser lube and eventually Lucas M8.

 

[ka0tyk]

i just have my mild bbc in front of my alpha. ive hit close to 5k rpms and i have a mirage 23p 3 blade on it with my bahner 21. remote resivoir and drive shower as well... well "halo". running quicksilver/merc normal blue fluid in it. so far no issues. kinda worried how its gonna hold up with my warlock 21 thats muuuch heavier.

 

[Rajobigguy]

Wow, stuff slips off the front page fast around here.
Anyone else pushing the limits on an Alpha?

 

[Bigbore500r]

I have never had one...but friends that I know have gone 8 seasons and more on the damn impeller inside the drive! It may be a PITA to change but I guess it works good huh?

 

[460]

Anyone with an alpha drive and a small block needs their head checked.

 

[crzy2bealive]

Haven't had a problem with my alpha

 

[77charger]

I have never had one...but friends that I know have gone 8 seasons and more on the damn impeller inside the drive! It may be a PITA to change but I guess it works good huh?

I went atleast 10 years on mine.It never ran warm at idle or speed.I had to drop the lower to get a propshaft seal replaced due to fishing line cutting it so i fugured i would have it changed then.The good thing is they never run dry since its already in the water when they start vs the bravo where the pump is in the engine compartment.

 

[77charger]

Anyone with an alpha drive and a small block needs their head checked.

Hey runs all day on fuel and still faster than the average jetboat.

 

[Rajobigguy]

Haven't had a problem with my alpha

Well actually I've had several alphas and never had a problem but they were in lighter ski boats and not pushing over 300 hp.
Now with a 24' deck boat and this arrangement I'm pretty sure I'm going to be pushing the limits.

 

[RiverDave]

I ha e heard of guys running 400+ HO through them and not breaking them. For smaller 21' and less boats I think they are better then bravos.. The smaller gear case is more efficient.

 

[Jimmy]

Would gear ratio and pitch of prop change the stress on the drive?

I'm only asking this because I'm in the process of repowering my ski boat with a bravo 3.
The drive is second hand with a 1:2.2 gear ratio which I think is too high and I'm yet to buy a prop for it.

 

[RiverDave]

Would gear ratio and pitch of prop change the stress on the drive?

I'm only asking this because I'm in the process of repowering my ski boat with a bravo 3.
The drive is second hand with a 1:2.2 gear ratio which I think is too high and I'm yet to buy a prop for it.

That's a question for the experts.. Read this though as it's pretty informative.

http://www.go-fast.com/sterndrive_gear_ratios.htm

At the bottom of it they do mention that the lower gear ratios do put some more stress on the drive, but I'm not sure that it's going to matter for a low HP ski boat application.. (You sure about that ratio BTW?)

 

[Jimmy]

That's a question for the experts.. Read this though as it's pretty informative.

http://www.go-fast.com/sterndrive_gear_ratios.htm

At the bottom of it they do mention that the lower gear ratios do put some more stress on the drive, but I'm not sure that it's going to matter for a low HP ski boat application.. (You sure about that ratio)

What sorta setup everyone else running?

I picked it up cheap. It come off 30ft fishing cruiser, got hit by a car.
When I come to stripping it down I'll check how many teeth it's got.
The mercury dealer in town sorta bluff there way though some of the stuff I ask them.

 

[OCMerrill]

What sorta setup everyone else running?

I picked it up cheap. It come off 30ft fishing cruiser, got hit by a car.
When I come to stripping it down I'll check how many teeth it's got.
The mercury dealer in town sorta bluff there way though some of the stuff I ask them.

The gear ratio is stamped on the side of the upper housing for an Alpha.

I use a 1.47 most common with V-8's. also 1.62, 1.8 and so on.

 

[96motorhead]

I went atleast 10 years on mine.It never ran warm at idle or speed.I had to drop the lower to get a propshaft seal replaced due to fishing line cutting it so i fugured i would have it changed then.The good thing is they never run dry since its already in the water when they start vs the bravo where the pump is in the engine compartment.

The raw water pump for a bravo doesn't run dry. The pump sits below the water line so it has water in it the moment the boat goes in the water.

 

[Flying_Lavey]

I'm really not too sure why everyone says the Alpha raw water pump is a PITA to change. They are the same lower units as the 2.4 and most 2.5 outboard lower units. I change mine in 20 mins on my outboard. Unless there is something that I'm unaware of that's different on the Alpha drive.

 

[twocents]

If you're going to put some horsepower to an Alpha (and expect 65+ mph speed) I'd seriously recommend upgrading the stock Alpha steering to external hydraulic -- IMCO Nevada has just come out with a new external hydraulic steering kit for the Alpha -- it looks pretty cool (single or dual rams).

 

[boatnam2]

I have the merc/alpha combo putting a blistering 260 hp to the prop, spinning a crazy 4100 rpm with a massive 17p labbed prop, well it not labbed but i bought it from a meth dealer who owned a lab and seeing speeds in excess of 40 mph with zero issues! Im thinking about even changing the oil in it next year, maybe!

 

[Runs2rch]

I have the merc/alpha combo putting a blistering 260 hp to the prop, spinning a crazy 4100 rpm with a massive 17p labbed prop, well it not labbed but i bought it from a meth dealer who owned a lab and seeing speeds in excess of 40 mph with zero issues! Im thinking about even changing the oil in it next year, maybe!

Your tach right? You need to spin that small block at least 4400-4600 to make hp. Our alpha's have been bullet proof on or 27ft Hallett. I think in twin apps they can easily run the 350-400hp reliably.

 

[ka0tyk]

1.62 and like i said. mirage 19 23p 3 blade.

 

[boatnam2]

One thing i can say about my set up no one else can is its the slowest motor brummet has ever built

 

[Jimmy]

1.62 and like i said. mirage 19 23p 3 blade.

That sounds about right, but I haven't looked too far into it.
So anything around 19-23p.
What about a bravo 3 twin prop?
The old drive I had a 1.5 on it.

 

[Jimmy]

I have the merc/alpha combo putting a blistering 260 hp to the prop, spinning a crazy 4100 rpm with a massive 17p labbed prop, well it not labbed but i bought it from a meth dealer who owned a lab and seeing speeds in excess of 40 mph with zero issues! Im thinking about even changing the oil in it next year, maybe!

Sounds like my ute [emoji1] just keep driving till it starts knocking. I got to a stage where I could push start it in a supermarket car park by myself [emoji41]

 

[boatnam2]

Sounds like my ute [emoji1] just keep driving till it starts knocking. I got to a stage where I could push start it in a supermarket car park by myself [emoji41]

Yea the amount i have invested in it, she just keeps running and running almost feel guilty not looking at her vitals! Nah! i had enough years of spending the weekend cleaning and waxing and oil changes and big payments now i just run her and put it away wet literally lol.

 

[UUG]

I just want to get a feel for how far you've taken your alpha drive and how long of a life you got out of it. I know Mercury rates them for 300 but I've heard that with the additon of a shower, a remote resevoir, and a 4 blade prop that you can run them @ 400+. In the real world is anyone doing this and what kind of boat and operateing conditions do you have?

In 1986, i ordered/purchased a new Welcraft Nova with a 454 mag/alpha package sporting a 1.32 ratio running a 21 quicksilver Lazer. Loved that boat, had for 10 years, never a problem. I watched re-entry engine/torque speed when flying wave tops, and kept it at wot. With slight head mods 2 years after warranty ran out including, manifold, carb and CMI uni's, spun at 4900-5k day in and day out. used for family tubing, water skiing and just having family fun- SF Bay, Delta and Tahoe. Changed outdrive oil yearly ran halo outdrive cooler. Never a problem for 10+ years til i sold. New owner decided to upgrade to bravo just for piece of mind.
with light boat and modest power and sensible driving, if clearances are correct, i see no problem- worked for me and i pushed the limit many times. Btw, only changed my cooling impeller twice in 10+ years on the Alpha which is better performance than my sea-pumps impellers hanging off my 502's.
enjoy!

 

[77charger]

That sounds about right, but I haven't looked too far into it.
So anything around 19-23p.
What about a bravo 3 twin prop?
The old drive I had a 1.5 on it.

I use a 21p 3 blade mirage on my 207 eliminator been the right size for me.I do have a19p for powell or heavy loaded.I tried a 4blade rev4 in 21p it was a lil too much and my 21p 3 blade has worked best all around mines a 1.50 ratio.

For my use i have found a 4 blade does not work for me.

 

[OCMerrill]

In 1986, i ordered/purchased a new Welcraft Nova with a 454 mag/alpha package sporting a 1.32 ratio running a 21 quicksilver Lazer. Loved that boat, had for 10 years, never a problem. I watched re-entry engine/torque speed when flying wave tops, and kept it at wot. With slight head mods 2 years after warranty ran out including, manifold, carb and CMI uni's, spun at 4900-5k day in and day out. used for family tubing, water skiing and just having family fun- SF Bay, Delta and Tahoe. Changed outdrive oil yearly ran halo outdrive cooler. Never a problem for 10+ years til i sold. New owner decided to upgrade to bravo just for piece of mind.
with light boat and modest power and sensible driving, if clearances are correct, i see no problem- worked for me and i pushed the limit many times. Btw, only changed my cooling impeller twice in 10+ years on the Alpha which is better performance than my sea-pumps impellers hanging off my 502's.
enjoy!

A 1.32 Alpha came behind those? Something I have yet to know and I know Alphas pretty well.

Changing an Impeller in 20 min is complete bullshit LOL but this thread is really shaping up.:thumbup:

 

[Bigbore500r]

The raw water pump for a bravo doesn't run dry. The pump sits below the water line so it has water in it the moment the boat goes in the water.

It is an engine mounted raw water pump, are you sure it is below the water line? My raw water pump is driven off the crankshaft snout (pulley) and i believe even that is barely above the water line

 

[UUG]

A 1.32 Alpha came behind those? Something I have yet to know and I know Alphas pretty well.

Changing an Impeller in 20 min is complete bullshit LOL but this thread is really shaping up.:thumbup:

yes, i hear it was only available 1 year when i ordered my Nova in 86. but my memory is a bit cloudy. not sure if it was a reliability benefit or the available props at that time to fit that combo.

looks like BAM still has the dealio avail.

http://www.mercruiserparts.com/Show...r=70&bdesc=DRIVESHAFT+HOUSING+AND+DRIVE+GEARS
part number 43-8M0080756 GEAR SET (1.32 RATIO) (16-20 GEAR RATIO)

btw, on a different note,
if i remember correctly, be careful on the 4 blade props, had too much 'hook-up' at the time and was frowned against if reliability was an issue unless the right 3 blade is used.
For me and for my application the laser 21 spinning at 5k was sweet. tried several others included the trick cleavers at the time and never worked well pushing that heavy deep v with a 20* deadrise

 

[OCMerrill]

yes, i hear it was only available 1 year when i ordered my Nova in 86. but my memory is a bit cloudy. not sure if it was a reliability benefit or the available props at that time to fit that combo.

looks like BAM still has the dealio avail.

http://www.mercruiserparts.com/Show...r=70&bdesc=DRIVESHAFT+HOUSING+AND+DRIVE+GEARS
part number 43-8M0080756 GEAR SET (1.32 RATIO) (16-20 GEAR RATIO)

btw, on a different note,
if i remember correctly, be careful on the 4 blade props, had too much 'hook-up' at the time and was frowned against if reliability was an issue unless the right 3 blade is used.
For me and for my application the laser 21 spinning at 5k was sweet. tried several others included the trick cleavers at the time and never worked well pushing that heavy deep v with a 20* deadrise

I completely agree on the 4 blade prop. I was running a 4 blade both times I blew the upper unit. I have a 23" pitch Solas I am running that has been tweak by cutting edge with more cup for bow lift.

 

[rrrr]

What about a bravo 3 twin prop?
The old drive I had a 1.5 on it.

Jimmy, I have a couple of B3 prop sets. When you figure out what you need, shoot me a PM. If I have what you need I'll give you a good deal.

 

[Rajobigguy]

OK, so the general soncensus is that that the Alpha will handle the kind of HP that I'm going to put into it as long as I dont try pull a hole shot on a flatbottom and dont go jumping wakes with it. I dont think those will be issues for me.
On another note about props. I've been running Pirahna 4 blade composite props for years on several different boats and love them (laugh if want). Things hook up well and deliver good top speed but the biggest hing is that they take a hit without suffering much damage and if you do bang one up significantly you can change one blade at a time.
Thats pretty important to me since I'm about about as lucky with prop hits as Tim is with wire transfers.

 

[Jimmy]

Jimmy, I have a couple of B3 prop sets. When you figure out what you need, shoot me a PM. If I have what you need I'll give you a good deal.

What the freight like to Australia ya reckon [emoji1]. I'll need something before Christmas we're coming into warm weather now.
Give us 6 weeks.

 

[Flying_Lavey]

Changing an Impeller in 20 min is complete bullshit LOL but this thread is really shaping up.[emoji106]

Like I said, if there is something different about the Alpha vs a 2.4 outboard lower unit, I'm not aware of it. I can change my water pump in my boat in 20 mins. Done it many of times. I change it every year.

 

[Jimmy]

Just got home, it's definitely a 2.20.
I was looking into it a bit, the higher the ratio the more pitch ya need on the prop to get the same speed out of the same amount of revs.
Say ya wanna do 50mph @ 4000 rpm
1.5 - 20p
1.6 - 21p (which most guys are saying)
1.67 - 22p
1.74 - 23p
1.82 - 24p
And I spose it'll all depends on what speed u want to peak with what revs with out losing torque.
There'd have to be a graph somewhere.
Then what's the difference between 2, 3 and 4 blade props?

 

[OCMerrill]

Like I said, if there is something different about the Alpha vs a 2.4 outboard lower unit, I'm not aware of it. I can change my water pump in my boat in 20 mins. Done it many of times. I change it every year.

It takes me 20 min just to find the lube pump and a pan to put the oil in.

i believe these lowers are very similar.

I just want to add to watch out for the small compression seal on the alpha or your upper unit drive oil will slowly leak out.

 

[Faceaz]

I completely agree on the 4 blade prop. I was running a 4 blade both times I blew the upper unit. I have a 23" pitch Solas I am running that has been tweak by cutting edge with more cup for bow lift.

Takes me about 20-30min on our sportmaster, but don't know about the alpha... I've been wondering about the 4 blade too. At idle I feel our 4 blade is hooked up allot more & is harder on the lower cause the roughness of the idle jerks it back and forth a bit. Our 3 blade was vented though, probably has something to do with it.

 

[Runs2rch]

I completely agree on the 4 blade prop. I was running a 4 blade both times I blew the upper unit. I have a 23" pitch Solas I am running that has been tweak by cutting edge with more cup for bow lift.

We run 21 Rev 4's. Switched from 23 Mirage 3 blades. What a difference! Bow lift, holeshot, and midrange are greatly improved. Lost a couple mph up top. Fuel burn is night and day better now.

 

[Flying_Lavey]

Takes me about 20-30min on our sportmaster, but don't know about the alpha... I've been wondering about the 4 blade too. At idle I feel our 4 blade is hooked up allot more & is harder on the lower cause the roughness of the idle jerks it back and forth a bit. Our 3 blade was vented though, probably has something to do with it.

I did my buddy's sportmaster a couple weeks ago and it only took about 30 mins also and that was with having to clean the old gasket off with a wire wheel.

 

[77charger]

We run 21 Rev 4's. Switched from 23 Mirage 3 blades. What a difference! Bow lift, holeshot, and midrange are greatly improved. Lost a couple mph up top. Fuel burn is night and day better now.

My 3 blade mirage was reworked and outdid my 21 rev 4 I could trim it higher and it stayed hooked up I also got more lift with the mirage it out did the rev 4 at every part. But the rev 4 was pretty decent out of the box it was just a crack to much plus I love the way my mirage works I should have had that prop copied it got killed when boss hit bottom had York repair it was t the same recently hill redo it and it's very close to what it was and happy with it again. Had a lil cup added.