Impeller Quality

JimS123

Fleet Admiral
Joined
Jul 27, 2007
Messages
7,952
I usually change impellers based on running time, not age. My target is 100 hours. We have several boats, thus the 3.0 liter Mercruiser gets little use. I usually change the impeller after about 6 years, and every time I do an inspection shows that I really didn't need to change it yet.

Had an overheating problem and had the impeller changed. The entire pump (not just the impeller) was changed 2 years ago. When the dealer was questioned he said they don't make the impellers like they used to.

The 2 year old kit was Sierra, not Mercury.

Is it true that the parts are crap today?
 

Rick Stephens

Admiral
Joined
Aug 13, 2013
Messages
6,118
No opinion. I used a Sierra kit in an Alpha 1 that I sold later that year, but not enough experience to judge. Seemed like a quality kit.
 

alldodge

Moderator
Staff member
Joined
Mar 8, 2009
Messages
40,581
I don't put a lot of stock in sierra but then again about everything seems to getting cheaper. The Alpha drive can get what was called run dry impellers and have said to be a good investment. I have Bravo's and no such thing for them

Use to change every other year, but have now installed a water pressure gauge. this way I can see how the impeller is doing. Going to try 3 seasons and pull apart to have a look. In most cases the impeller gets flattened over the winter and does not spring back as well in the spring. Alpha Gen 2's have been lasting much longer
 

thumpar

Admiral
Joined
Jun 21, 2007
Messages
6,138
I use Sierra but also change mine every 2 years.

AllDodge Globe makes a run-dry for the Bravo. I have thought about using one with the Hardin stainless housing.
 

Scott Danforth

Grumpy Vintage Moderator still playing with boats
Staff member
Joined
Jul 23, 2011
Messages
47,297
Rubber only knows calendar age...... Heat and friction artificially age the rubber. Fillers, binders and coloring agents shorten the life.

If the rubber is coming from an off shore source, it could be of lower quality
 

Grub54891

Vice Admiral
Joined
Jun 17, 2012
Messages
5,908
Run dry impellers work fine, IF they are below the waterline. If they are inside the boat, and have to lift the water up, they don't always prime easily. Seen them not work in a few boats already this season, they are made of a softer material, and flex to much to pull water uphill.
 
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