Alpha one gen 2 water pump replacement

Q: What is the difference between alpha 1 and Gen 2?

Alpha Ones have two studs under the ventilation plate just above the prop. Alpha Gen II drives do NOT have two studs with nuts above the prop.

Q: What size prop does an alpha one take?

UNK Propeller 14.25 x 21 Prop for Mercury Mercruiser Alpha One 3-Blade Aluminum with Complete hub kit 14 1/4 x 21.

Q: What year is a MerCruiser Alpha One?

MerCruiser Alpha Gen 1 Outdrive (1973-1991)

APO/FPO, Alaska/Hawaii, Algeria, Angola, Benin, Botswana, Burkina Faso, Burundi, Cameroon, Cape Verde Islands, Central African Republic, Chad, China, Comoros, Congo, Democratic Republic of the, Congo, Republic of the, Cook Islands, Côte d'Ivoire (Ivory Coast), Djibouti, Egypt, Equatorial Guinea, Eritrea, Ethiopia, Fiji, Gabon Republic, Gambia, Ghana, Guinea, Guinea-Bissau, Kenya, Kiribati, Lesotho, Liberia, Libya, Liechtenstein, Luxembourg, Madagascar, Malawi, Mali, Mauritania, Mauritius, Mayotte, Morocco, Mozambique, Namibia, New Caledonia, Niger, Nigeria, Niue, Palau, Papua New Guinea, Reunion, Russian Federation, Rwanda, Saint Helena, Saint Pierre and Miquelon, Senegal, Seychelles, Sierra Leone, Somalia, Swaziland, Tanzania, Togo, Tunisia, Tuvalu, US Protectorates, Uganda, Ukraine, Vanuatu, Vatican City State, Western Sahara, Zambia, Zimbabwe

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What is the difference between alpha 1 and Gen 2?
What size prop does an alpha one take?
What year is a MerCruiser Alpha One?

I was told by my local Mercruiser mechanic I should have the water pump replaced every 3 season. I just bought the boat and do not want to take anyone's word for it how old the pump actually is. With that said I will be changing out the water pump in the lower unit in the next couple weeks.

Here is the Kit I plan on purchasing, along with gear lube, and grease what else will I need?

Kit comes with.

Does the guide tube need to be replaced at this time?
Is there anything else I should be looking to replace while I have the lower unit down?

Thanks in advance,

Re: Changing water pump for Mercruiser Alpha 1 Gen 2

I have seen both video's.. Those video's are great and the reasons I'm going to tackle this job myself

My plan is to do it like the video you posted, rather than taking the whole lower unit off.

Thanks guys

Re: Changing water pump for Mercruiser Alpha 1 Gen 2

I just bought the boat and do not want to take anyone's word for it how old the pump actually is........My plan is to do it like the video you posted, rather than taking the whole lower unit off....

How do you know when the last time the ujoint bellows was checked for water or gear lube? Ujoints operate properly? Gimbal bearing is rusty, won't turn freely and needs to be replaced? Engine alignment correct? etc, etc.

Pull the entire drive and replace the water pump with the complete drive off the boat.

Mark

Re: Changing water pump for Mercruiser Alpha 1 Gen 2

How do you know when the last time the ujoint bellows was checked for water or gear lube? Ujoints operate properly? Gimbal bearing is rusty, won't turn freely and needs to be replaced? Engine alignment correct? etc, etc.
Pull the entire drive and replace the water pump with the complete drive off the boat.
Mark

Agree! +++

The guide tube is only there to assist in guiding the water tube during reassembly.
It serves no purpose once the drive is together.

It is a bear to try to align the lower onto the upper.
You have to lift and hold it while trying to get the bolts in and do it all at an angle.
You'll need 5 hands and three eyes.
It is much easier to just lower the upper onto the lower off the boat. Straight down, working with gravity.
Plus it gives you a chance to inspect the innards of the upper.
Mine had a water leak, new from the factory that would have damaged the shift assembly if I had not caught it.

While it is off you can do your annual engine alignment and check the bellows.
They only last two or three impellers.

Re: Changing water pump for Mercruiser Alpha 1 Gen 2

I have seen both video's.. Those video's are great and the reasons I'm going to tackle this job myself

My plan is to do it like the video you posted, rather than taking the whole lower unit off.
Thanks guys

As stated by others you should pull the whole drive and check it all so you can start with a fresh baseline so you know for sure when everything was checked and or replaced. Here is the Merc service info for replacing the impeller on your alpha 1 gen 2 drive:

View attachment A1G2 Impeller Replace.pdf

and here is the complete manual:

Boatinfo - Mercruiser Service Manual nr. 14 - 1991-Current - Sterndrives Alpha One Gen II</