impeller change on '97 Mariner 125

[quantumleap]

this will be the 3rd season I've had this motor and I haven't changed the impeller yet. The guy I bought it from said it had been done recently before he sold it (how long 'recently' is I don't know). I realize that it is probably overdue for this service, but if you have a great stream coming out of the peehole even on muffs at idle, isn't the impeller still doing its job, or is the risk of it breaking up and lodging pieces of rubber in the cooling passages the main reason for regular replacement intervals?

 

[andrewkafp]

Re: impeller change on '97 Mariner 125

I have exactly the same situation. 1980 50hp Merc 6-7 PSI from pump at 5000.. Stream warm to touch stays cool and whole pump/casing done late 2000.<br />You need to crack off that L/U every couple of seasons to keep the shaft greased for easy removal along with getting used to doing your preventative maintainence. I have an auxiliary motor which will get me back if I see a pressure drop in the telltale, but that won't help if the impeller breaks up leaving plastic pieces floating around the cooling system.<br />Best that you bite the bullet and do it in the off season. That's the concensus here on iboats.<br />BTW The previous owner of my boat religiously got it serviced yearly (Have the receipts). It has brand new switchbox,trigger, rectifier, steering cables and he paid lots for them. When I went to remove the prop to grease the shaft, it virtually slipped off in my hand. Big relief when you read on here about cutting, heating, belting them off.

 

[jim dozier]

Re: impeller change on '97 Mariner 125

The thing is, they are made of rubber. Besides taking a set (loosing flexibility) and loosing some of their ability to pump at low speeds, they can crack and throw off pieces which will, by Murphy's law, lodge in the place where they will do the most harm and be the most difficult to remove. And like Unicorn said, if you replace it every other year the bolts won't get frozen in the lower unit.

 

[quantumleap]

Re: impeller change on '97 Mariner 125

thanx for the replies. I have been planning to replace it before I run it this spring. I am picking up the kit today and will do my first pump rebuild Friday night. Doesn't look to be too difficult.

 

[quantumleap]

Re: impeller change on '97 Mariner 125

Hey it looks like I'm a captain now.

 

[quantumleap]

Re: impeller change on '97 Mariner 125

Well, I couldn't stand the suspense, so I did the pump rebuild last night and thanks to the words of wisdom from this board, all went well. About and hour and a half from start to finish. I think it'll take aboout half the time next year. You guys are right, the manual makes it easy. The old impeller initially looked to be in good shape but a bit more flexible than the new one. At first I thought I could have gotten another year or two out of it but after thinking about it, if you took it apart and the impeller was shot, then you probably waited too long and could have caused powerhead damage. I guess that's why they call it 'preventative maintenance'. Just like on a car, you don't want to wait for the radiator hose to burst before you replace it. Anyhow, thanks for all the informative posts on this topic that helped me save the labor expense and gave me the peace of mind that the job got done right.