Biggest motor in front of alpha 1

S

Scott215

Well-Known Member
Jun 4, 2022
2,199
Boat Info
2006 215 weekender 5.0 mpi
Engines
5.0 mpi alpha 1 gen 2
What is the biggest motor that mercruiser put in front of an alpha 1 with the water pump in the outdrive. Meaning did they have a impeller in the outdrive cooled big block at some point in time or how much horsepower did they have at some point in time being cooled from the outdrive just curious
 
Thank you I appreciate it
 
Was curious because of the amount of water needed to cool a V8, the impeller in the outdrive must pump a lot of water
 
I ran that combination. And yes, the 454 is too much for the Alpha. Merc did not offer that combination for long. As far as the Alpha pump cooling a big block... yes it can, but many of us found the temps in warm water could creep up. Putting a little aluminum plate behind the intake grate did help to force more water in.
 
@keokie. Thank you was curious how much water an alpha can pump. Thanks again
 
So is a drive shower really needed on a 5.0 MPI alpha gen 2
 
No it still has a blue color to it I was just wondering about the water pressure and output of that drive keeping a motor cool that's all just curious you guys are great as usual
 
An alpha is limited to 300hp
As boats got bigger and heavier and needed more HP that is when Mercruiser developed the Bravo series.
Drive showers are needed mostly for high torque engines, more torque means more heat develops in the gear boxes.
You see them most often when someone converts the water pickup to a thru hull. You still need cooling for the drive.
 
Scott215 said:
@keokie. Thank you was curious how much water an alpha can pump. Thanks again
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An Alpha Gen II water pump is much better, more efficient than the engine mounted Bravo pumps. The impeller is larger and runs at a lower RPM (same RPM as the propshaft). It is pushing water, not sucking it. They are more of a PIA to change being in the outdrive, but they also tend to last longer.

But like others have said, they are not built to take the torque of a big block, about 300hp is the limit. But for smaller motors, they are just rock solid.
 
I was just curious as to wanting to know if the volume is sufficient for an alpha 1 Gen 2 with a small block that it has adequate cooling without having to do any modifications such as a drive shower
 
The drive showers help immensely on the Bravo 3's, as they tend to run the hottest. Not a problem at slow speeds, but as the boat gets on plane, the drive above the anti-ventilation plate is fully out of the water and has minimal cooling through the water flow to the pump and typical splash..
 
Scott215 said:
I was just curious as to wanting to know if the volume is sufficient for an alpha 1 Gen 2 with a small block that it has adequate cooling without having to do any modifications such as a drive shower
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The shower is really only a concern on the Bravos as they don't run the water through the drive the way the Alphas do. The Alphas have a large water jacket running up the back of the gear housing that the water pump uses as passage to the engine, so all of the cooling water for the engine first travels through the gearbox. Too bad they didn't keep something similar on the Bravos, but I suppose you wouldn't want to add any more restriction to the pump's suction side than is already there. Can you say "Bravo-itis"?
 
Thank you for the insight
 
Nater Potater said:
The shower is really only a concern on the Bravos as they don't run the water through the drive. Too bad they didn't keep something similar on the Bravos, but I suppose you wouldn't want to add any more restriction to the pump's suction side than is already there. Can you say "Bravo-itis"?
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Stop fkn with me Potato man! 2021 was a bad summer! I know the term well!
 
Pirate Lady said:
Stop fkn with me Potato man! 2021 was a bad summer! I know the term well!
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Touchy, aren't we? Lose at the track today? :p @Scott215, don't let @Pirate Lady mess with your groove. He's still butt-hurt from losing a whole summer over a simple overheating problem. Maybe he'll send us the link. You might be able to find it in the Joke thread...
 
Scott215 said:
I was just curious as to wanting to know if the volume is sufficient for an alpha 1 Gen 2 with a small block that it has adequate cooling without having to do any modifications such as a drive shower
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A drive shower is only relevant to the drive - not the engine. With a small boat like the 215, a drive shower (while it can't hurt) would be waste of money.
 
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