Mariner 4HP Impeller changing

[Mick Bull]

Hi guys, a new Limey here.
Can anyone tell me how to start to change the impeller on a 4HP Mariner (early 90's). Every post I find on the net says buy a book - I want somebody to actually answer the question.
I have split the lower gear box unit from the leg but it will not just pull out so I stopped there for the time being. There is a large hole in the leg and through this I can see a clamp bolt fixing 2 rods. Is this the culprit holding it all in place?
Hope somebody can answer this
Cheers
Mick

 

[MrGED05]

Re: Mariner 4HP Impeller changing

Mick,
This isn't an exact answer to your question but the two shafts you see extending into the lower gearbox are the main propeller dirive shaft and the "forward/reverse" gear selecter shaft. On a small Mercury outboard, these shafts have splined top ends that connect/slide into the leg. They're a tight fit on a Merc but they're not fastened together inside the leg or at the powerhead. I can tell you that bending either one will create a basket full of heartache for you. Don't ask me how I learned that. The answer is ugly.

 

[TOHATSU GURU]

Re: Mariner 4HP Impeller changing

Once you remove the two bolts holding the leg on you remove the rubber grommet and loosen up the bolt holding the upper and lower shift rods together. The reason you see the "buy a service manual" all over the net is because you need to buy a service manual if you are going to be working on your own engine. A visual guide is priceless and you are asking for trouble by not investing in one.