Impeller replacement in Alpha drives

[BarryB]

I have a 2005 280DA w/200 hours. It has T4.3's & Alpha drives. I cannot find in the owners manual where it says I should replace the impellers, but my dealer says they should be replaced as part of the 200 hour service. I boat in brackish water and the temp guage is always within the normal range. Can anyone here tell me if the additional cost of replacing the impellers is worth it at this time? It seems that this would be an expensive procedure as the estimate is 2.5 hours labor on each drive.

Thanks in advance for your help.

 

[osd9]

maintenance is cheaper than repair..... plus the peace of mind...... :thumbsup:

Replacing an impeller on an alpha drive is not that difficult if you are even moderately inclined....basic tools, some knowledge which you can easily get from this board if you ask, and a little muscle to lift the drive......

 

[BarryB]

I've done the oil, filter & fuel filter changes, as well as, cleaning the flame arrestors. Unfortunately, I do not have a trailer or the means to get at the drives. I keep it in a slip and the dealer will have to take it out of the water. Thanks for the advice.

Barry

 

[osd9]

BarrY;

Does the estimate from your yard include the Haul out? You need to confirm the TOTAL estimate: Parts, Labor, Haul. In my first post, I assumed you were already out of the water.

Generally, when you haul to repaint and install new zincs is a good time to do the outdrive maintenance. When I had alphas, I used to change the gear oil every year and the impellers every other year...typically less than 100 hours per year.

good luck,

 

[BarryB]

The 2.5 hours of labor are just for changing each one of the impellers. All parts are extra. They also will be pressure washing the bottom, installing new anodes, changing the gear lube oil, and painting the outdrives. I don't know if they will be aligning the engines or any other service items I am unable to do. I just know it will be quite a few $$$$, but that's all part of this hobby! The reason I asked about the need for the impellers to be changed at 200 hours is because I know it will add quite a bit to an already large bill.

 

[jhild]

I was contemplating changing my impeller (3.0L / Alpha) last spring and had some of the same concerns. Ultimately, I was convinced to wait until the end of the season instead. Here's what I got for a general consensus after polling a few local boaters, dealers, and mechanics (including my own.) Do with this as you please!

1. The water pumps in the 4.3 (and my 3.0, for that matter) are the same as those used on the 5.0L Mercs. Essentially, the volume of water flow (i.e. cooling ability) of your pump is more than your engine really needs. You should have sufficient cooling power even if your impeller is not functioning at 100% efficiency.

2. It's not really fresh v. brackish v. salt water that makes the biggest difference. Impeller life is determined more by the amount of sediment in the water where you boat. For example, if you travel in shallow water a lot, you’re more likely to kick up debris which will get sucked into your cooling system causing impeller wear.

3. There were issues with the pumps & impellers in older alpha drives which has created a sort of urban legend with regard to impeller lifespan. The newer units are (apparently) engineered to last longer.

4. Generally speaking, the time to address the impeller is while the drive is already apart for other routine (or emergency, I suppose) maintenance. Try not to make a special project out of changing the impeller. ($$$)

I waited 3 seasons before making the change, and my impeller was still in good shape. (And I spend a fair amount of time in shallow brackish water.) I’m sure some people have blown through them in 50 hours. I bet others have gone 10 years without a problem. Ultimately, only you can decide whether it’s worth waiting or not. Just keep an eye on the temp gauge and you'll probably be fine, but who knows? One last thing to think about: If you cook your motor because you didn’t follow Merc’s recommended maintenance schedule, you’ll be looking at a much bigger bill.