How many water pumps?

[Tahoe 55]

Re: How many water pumps?

Thanks all. Sorry, but this has been sort of a wild goose chase...
I looked at the engine this weekend and I don't have a engine mounted raw pump. I could have swore I had seen one one there, but I must have been thinking of the pictures I've seen of the 5.0 MPI....

Thanks again and sorry for the confusion.

 

[QC]

Re: How many water pumps?

'sawright . . . Thanks for the update Either way the impeller still needs to be changed every couple of years.

 

[Tahoe 55]

Re: How many water pumps?

Thanks, I'll be sure to change it.

 

[HT32BSX115]

Re: How many water pumps?

Maybe I don't have a belt driven RAW water pump...
When I said left, I meant Starboard side.
I'll check for this pump and report back later.
Thanks for the help so far.

I was just reading on how to change the water pump in a Alpha drive and it sounds very complicated... Is this true?

Well, no. not really.... after you drain the oil you just "drop" the lower unit and remove the 4 6mm bolts to remove the housing, impeller and plate.

Get yourself two 3 inch or longer 6mm x 1.00 bolts and cut the heads off.
After you file the burrs you can use them as guides (as shown in the service manual) when you put the (pump) housing back on.
(there's special Mercruiser "tools" that do the same thing....but the bolts are probably a little cheaper)

As an aside, I just changed one last week on a 94' GEN II that the owner swears had NEVER been changed....(looking at the rest of the boat I believe him!) It was in remarkably good condition! It was clearly worn but the vanes were still pliable and doing the job. I wouldn't intentionally run one that long but it's nice to know that one could go that long....

 

[Tahoe 55]

Re: How many water pumps?

Thanks for that info. I read a how-to article and they made it sound very complicated.... A lot more so than I thought it would be..

From your last comment, it sounds like Merc's. maintenance schedule should be right on with recommending replacement at 200 hours or 2 years?...

 

[HT32BSX115]

Re: How many water pumps?

Well,

I had to have a look at #14 again and it actually says to

( page 1b-3 )
[ANNUALLY]

Disassemble and inspect seawater pump and replace worn components.

I think experience has shown that in fresh water you can probably do this about every 2 years or so... (my friend let his go since 94!!)

 

[Tahoe 55]

Re: How many water pumps?

Hmmm... I'll have to look at my owners manual again tonight. I thought it said 200h. My dealer had said to do it as part of the winterization each year. He wants $300 to winterize....

 

[QC]

Re: How many water pumps?

You are supposed to check the drive alignment every year too, so that has you taking the whole thing off and then splitting the lower from the upper . . . I have to admit that I stretch both, but I'll post a picture of why you shouldn't stretch pump impellers although I got lucky this time . . .

 

[Don S]

Re: How many water pumps?

With the Gen II drive impellers, I always recommend to my customers every 3rd year. They are usually in usable condition, and just starting to show their age.

 

[HT32BSX115]

Re: How many water pumps?

I know I implied that my friend never changed his since the boat was new (it's a 1994 model) but in fact he bought the boat in 1998. He never had the raw pump changed (he said) and for that matter never had the drive oil changed either. The oil didn't look all that bad (it was Merc HP oil and it was somewhat green)

I am amazed that the raw pump hadn't failed in the last 10 years but I don't think he's used the boat much in that time.

I know the one in my old 66 150 Mercruiser that Dad had did not get changed until I changed it. That was almost 15 years. It was in pretty bad shape!!

I always find it amazing that some think that you can maintain a boat like a car (zero maintenance)

 

[QC]

Re: How many water pumps?

Here's a three year old Bravo impeller. I got really lucky as it failed on me about 12 miles from the Marina, I was idling out of a cove after hanging on a hook for a bit, getting things situfied and the alarm went off . . . Wasn't pumping a drop out my thru transom exhaust at idle, but it would just start to dribble at 1000 RPM +. Nursed her home on plane without overheating, pulled it apart that night and I could not believe this pumped anything:

Almost 100% freshwater although I do beach her some . . . Around 250 hours and I changed the housing when I did it.

 

[Don S]

Re: How many water pumps?

How a Bravo or an Alpha I Gen I impeller acts and reacts to use and age is completely different from an Alpha I Gen II impeller.
You're comparing apples to oranges, it doesn't work very well in this case.

 

[HT32BSX115]

Re: How many water pumps?

Yeah they are different. On that Gen II I changed last week, even though it was 10 years old, was still flexible and soft. It looks like the rubber they use is quite a bit different from the Bravo or older Alpha Impellers.

When I changed the bravo impeller in mine before I put the engine in I almost didn't because the previous owner told me that he changed it at the end of the summer before and didn't use the boat much before the tree fell on it that winter...

The impeller wasn't all that bad I guess but I changed it anyway and then I found all the vanes from a previous failure still crammed in the oil cooler.....I was going to believe him and wouldn't have checked the oil cooler......but a little birdie was whispering to me...

 

[QC]

Re: How many water pumps?

How a Bravo or an Alpha I Gen I impeller acts and reacts to use and age is completely different from an Alpha I Gen II impeller.
You're comparing apples to oranges, it doesn't work very well in this case.

I agree, but some people like to take a bite of an orange and then an apple . . . Just thought it might be interesting . . .