Alpha One Gen 2 impeller delete question

[subcrx]

I have a 87 Bayliner with a Chevy 350 with a Alpha 1 Gen 2. Closed cooled for the ocean. The impeller broke out at the middle of nowhere and had to get a 5 hour tow back in from the island. I have worked on some Volvos that have the impeller on the crank. Is it possible I can just remove the impeller on the drive and install a crank driven impeller. That way I can keep a spare impeller and change it out on the water if it goes out again? I’m sure this has been asked before, and wondering if anyone has done it. I think whoever designed an out drive with the impeller inside so it has to be split to change should be hanged.

 

[dubs283]

Alpha 1 Gen 2. Closed cooled

Mercury factory closed cooling alpha set up came with an engine mounted, belt driven sea water pump. Same as a bravo/mie setup.

Reason was the pump in the drive could not supply enough sea water flow to the heat exchanger to adequately cool the coolant. They left the drive pump intact but severed the hose between the bellhousing and the gimbal housing to just dump the water back into the lake/river/wherever and blocked the thru fitting. Thus still allowed for cooling of the drive during operation

It's possible your setup is aftermarket and does not utilize the above setup. If so, it's your boat, do with it what you like

 

[subcrx]

My closed system is aftermarket. So you think the crank style impeller could pull enough water up through the drive to keep everything cool?

 

[dubs283]

So you think the crank style impeller could pull enough water up through the drive to keep everything cool?

I have no idea, I only mentioned what I did because it's what I'm familiar with. If I were curious I'd contact whoever designed the system you have and ask them about their opinion/recommendations

 

[kenny nunez]

Mercruiser also recommends using the drive pump along with the crankshaft driven pump when pulling water from the bottom and connecting them with a “Y” pipe setup. Since there is a sea valve you can shut it if you want to run the boat on a flush out.

 

[Scott06]

Mercruiser also recommends using the drive pump along with the crankshaft driven pump when pulling water from the bottom and connecting them with a “Y” pipe setup. Since there is a sea valve you can shut it if you want to run the boat on a flush out.

This is the correct way to install a fresh water system on an alpha.

to the OP before you hang anyone, look and see if there is room, and if that will be any easier to change. Some of the comments folks have made about the contortions they need to do to change a belt or crank pump makes me think theres no free lunch.

ive found the oem merc gen 2 impellers to be very durable. How old was the impeller and was it oem?

 

[achris]

... How old was the impeller and was it oem?

This is my first question too....

 

[subcrx]

This is the correct way to install a fresh water system on an alpha.

to the OP before you hang anyone, look and see if there is room, and if that will be any easier to change. Some of the comments folks have made about the contortions they need to do to change a belt or crank pump makes me think theres no free lunch.

ive found the oem merc gen 2 impellers to be very durable. How old was the impeller and was it oem?

Impeller was about two years old. Not oem. I pulled it out it completely ripped itself apart. I have lots of room to install a crankshaft pump.

 

[Scott06]

Impeller was about two years old. Not oem. I pulled it out it completely ripped itself apart. I have lots of room to install a crankshaft pump.

You can do as you like but if you spend $55 for an OEM merc impeller and change it every 3 years you wont have this issue.

Do you recall if that is an SEI impeller? one of the professional mechanics who is on the marine engine forum mentioned that happening with their impellers

I just changed my gen 2 impeller last fall after 6 years, did my neighbors that was over ten years old; both looked perfect. I found on my gen 1 the Sierra impellers last half as long as OEM.

@achris - you go off shore right? How many gen 2 impeller failures have you had ?

 

[achris]

@achris - you go off shore right? How many gen 2 impeller failures have you had ?

Easy answer. None... But then I only use genuine. And that goes for all my friend's boats (that I service) too.

Chris ..