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Mercury impeller R&R

wipermaker's Avatar

Join Date: Nov 2008
Posts: 1

11-05-08, 08:24 AM   #1  
Mercury impeller R&R

Hi have a 50hp Mercury ob that needs a water pump impeller and I have no manual. Could someone tell me how the lower unit should be taken off and any tips that you know?

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samuari's Avatar

Join Date: Jul 2008
Posts: 541

11-05-08, 05:45 PM   #2  
The gearcase removal is different depending on what year and 2 or 4 stroke but I can give you the basics. First pull the teather cord or do something so you are sure it CAN'T START as you will be working arround the prop. Shift the controll box into forword gear it makes it easier to reinstall and trim the motor up. Next remove the tourque tab at the back of the gearcase there are 2 bolts under it. Then remove the rest of the visible bolts holding the gearcase on. At this point the gearcase should be loose and will slide out the driveshaft will come out with it. The impeller is under the black housing arround the driveshaft. Make note of the direction of the fins on the impeller this is important. You will need to turn the driveshaft when installing the black housing to get the fins to turn in the correct direction. You will need to turn the prop to get the driveshaft to line up with the crankshaft.

That's the long and short of it Good luck.

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