Replacing impellar on Mercruiser 350MPI Horizon

[1Moredrift]

I have the 350 MPI horizon, bravo 1 with the water pump on the lower right (if your looking toward the stern)of the engine block. This will be my fourth year with the motor and I have'nt replaced the impellar yet. How difficult a job is this and should I replace more than the impellar? Any advice is appreciated.

 

[TilliamWe]

Re: Replacing impellar on Mercruiser 350MPI Horizon

Not too difficult. Should only have to loosen serpentine belt (one bolt on an idler pulley), then undo the two hoses on the backside of the pump (they can be awkward to reach), then 2 bolts in the bracket that hold it to the engine block. At that point you can lift it out & work on it on a bench. The hoses are slightly difficult, and putting the pump back together can be hard, to get the new impeller in there, and all the pieces lined up.<br />As far as anything else needed to replace, there is a wear plate in there, if it's not worn too bad, it's reusable.<br />I changed my impeller while being towed through a lock, and it took me about 1.5 hours total. And that was working around really hot exhaust manifolds. And had to take great care to have the intake hose higher than the water, or water would have run in the boat!

 

[Don S]

Re: Replacing impellar on Mercruiser 350MPI Horizon

A lot depends on how much room you have around your engine. Are you sure about the location <br />

with the water pump on the lower right (if your looking toward the stern)of the engine block

I've always seen them on the Starboard side on Mercruisers.<br />You really need to get a Mercruiser manual if you are going to do your own work.<br /><br />

 

[1Moredrift]

Re: Replacing impellar on Mercruiser 350MPI Horizon

Thanks guys,<br /><br />Don S. - I think are right, I am not sure why I thought it was on the right. How oftern does the whole pump need to be replaced vs just the impellar?

 

[Don S]

Re: Replacing impellar on Mercruiser 350MPI Horizon

How oftern does the whole pump need to be replaced vs just the impellar?

The impeller should be replaced at least every other year. No certain time for the pump, do you have the brass pump or composite pump? They make replacement housings for the composite pump.