View Full Version : Mercruiser IO How do I change the Impellor

04-10-2006, 10:48 AM
"Hi all I'm new to this and was wondering if anyone could help... I have a 1988 17' Stingray with a 3.0 Mercruiser and an Alpha 1 outdrive. I took the boat out and it was overheating pretty bad, I did run the boat out of the water with a garden hose going to the water pump. From what I've seen here it sounds like i tore up the impellor pretty bad. I hear it's a pretty easy/cheap fix, but I have no idea where to start or how to go about it. could someone help me with changing the impellor on this?"

04-10-2006, 11:03 AM
"You need to remove the lower gear case and you'll see a tube coming up from the pump. The drive shaft drives the water pump. Get a manual, because you'll need it to see what/where all of the parts are and how to dis/reassemble it. If you tore up the impeller, you'll need a water pump repair kit, not just the impeller. Impellers should be replaced annually if the boat sees more than about 75 hours/yr, expecially if you are in brackish or salt water."

04-10-2006, 01:26 PM
"You need a manual. The SELOC manual advertised here is a good one.
You also need to find all the little chunks of the old impeller. They will block cooling flow.
And... in case no one has nmentioned it, you need to buy a manual."

04-10-2006, 02:48 PM
Do you guys know what the part number would be for this water pump repair kit?

04-10-2006, 02:48 PM
"the one that includes the housing, gaskets, and the impellor"

04-10-2006, 03:42 PM
"All Mercruiser parts are referenced by the serial number of the motor or drive, so I would call a Mercruiser dealer and give them the serial #, then get the Merc part #. Whether you use Sierra parts or Mercruiser, it's your decision but in my experience, the Sierra parts work fine. They have a couple of different kits for that drive, so you'll need to make a couple of calls. If you toasted the old one bad enough, I would replace the upper and lower housings because if it's warped, it'll leak and take out the whole drive if you let it."

Harves Marine
04-10-2006, 04:18 PM
"If you are new to this and do not have history on the boat, pull the whole outdrive off and see inside the bellows. The ujoints can get greased and you can see if there has been water in the bellows. Get a good manual there are some things that will save your butt."

04-10-2006, 06:35 PM
"You could see some of the Sierra kits here ("").

As stated above, you should detirmine your serial number first."

04-10-2006, 06:57 PM
"So I took the prop off, and was having a hell of a time messing with it, i decided that maybe I should just pay someone to do it, so I went to put the prop back on, and my o my, that thing just will not go on!! ;0 arrr,,,, hehehe, needless to say, it was a bit upsetting.... am i retarded? how do you get this prop back on?"

04-10-2006, 07:00 PM
"I heard someone say use a floor jack w/a piece of wood, which I did, and it still wont go in,... I cant remember the last time a piece of machinery pissed me off so bad... I saw in another posting that the first time this is done it takes 3 hours, the second time 30min. i can see that... any ideas or help that could save some one else the pain of this would be great! thanks"