Friday, June 3, 2011

How do you change the water pump impeller on a Mariner 8 hp outboard motor?

I have separated the Mariner 8 hp lower unit from the upper unit , taken apart the water pump, replaced the impeller and pusher the lower unit up on to the upper unit. It guides on fine until the last inch. It feels like the drive shaft is not alligning with the engine drive acceptor socket. The shift linkage appears and feels to be in place. The exhaust down tube feels like it is lined up. I tried turning the prop to rotate the drive shaft but it wont go together that last inch. Can some one help ????How do you change the water pump impeller on a Mariner 8 hp outboard motor?you may have to put the lower unit in fwd gear so as you are pushing up you can move the prop and the drive shaft at the same time to aid in aligning the splines.How do you change the water pump impeller on a Mariner 8 hp outboard motor?Ensure the %26quot;male%26quot; notch is inline with the %26quot;female%26quot; notch?How do you change the water pump impeller on a Mariner 8 hp outboard motor?okay..listen up, first you need to make sure you have removed the internal rotation drive modulator from the outer expulsion shaft. once you have done that you can safely align the exterior drive acceptor socket. if you put too much torque on the alternating drive train adaptor, you will snap the linkage and possibly damage your fuel cell resistors.



thanks for letting me waste 30 seconds of your times cause I really have no clue. good luck, though...I would take it to a boat shop and have them do it.



might be your best betHow do you change the water pump impeller on a Mariner 8 hp outboard motor?G'Day Sailinguy,

I have done water pumps on a few different brands of outboard motors, not a Mariner though, but they are all basically the same. The first and most important thing to observe is the water tube is correctly mated to the power head or you will damage the motor through overheating. Make sure the gear shift is in a position that makes the linkage at it's lowest point in the leg, so that it can be connected and tightened later. Ensure the gear box is in the matching position, this is usually in the forward position. If the motor is still on the boat, tilt it up to the maximum position as it makes replacing the gear box assembly a bit easier. Slide the assembly into the leg and keep checking all is going where it is supposed to be going.

Once the drive shaft is starting to engage the crank spline do not twist the gear box, instead rotate the propeller clockwise and anti-clock wise through about a 1/4 turn, as you continue to GENTLEY push the gear box, until it engages and slides home. Insert a bolt hand tight and relax, put the rest of the bolts in and tighten in sequence so as not to stress the casing and possibly fracture it, tighten to the required torque and your done.

IMPORTANT NOTE:- DO NOT USE THE BOLTS TO %26quot;PULL%26quot; THE GEAR BOX HOME. This may damage the spline if it not lined up correctly or strip the thread in the casing. Also if you have cleaned off all of the grease it would be wise to re-grease the spline with the recommended marine grease. I hope this is of some help.