'89 Mercury 50HP Impeller problems

[Proffs]

Hi all,

I've been on AFO for a long time but rarely post. Anyhoo, I've got a 14ft glassy with what I'm pretty sure is an'89 50HP Merc on the back (3 cylinder 2 stroke). It's been a while since I've had her out, as my wife just had our first child 8 weeks ago. So, I cleaned her up recently and realised that when I ran the motor, water would only come out of the "pee pipe" when it was in gear; either forward or reverse. When I ran it in neutral for more than a couple of minutes an alarm would go off.

So, I'm guessing this is a problem with the impeller, seeing as though there's no blockage, and was just looking for advice on anything related really; where to buy an impeller kit, how to pull the LU down, if I'm even on the right track thinking it's the impeller etc.

The boat lives at Moorooka and I think the serial of the donk is 9553352.

Thanks in advance!

Edit: I've seen vids on how to replace the impeller on newer mercs and it seems fairly straight forward but I thought I'd get a heads up first.

[aussie123]

The alarm will be the overheating alarm.

Not being started for a fair while could be a buggered impeller or sticky thermostat but more than likely the impeller.

There may also be an ants nest or wasp nest in there causing a blockage.

You would need to drop the leg off the motor and inspect the impeller setup to see if you can get away with just a new impeller or whether you are better off fitting a whole new water pump kit.

Its an easy job to do and will take an hour all up at the most.

Change your gearbox oil while you are at it so you know the seals are good and no water has entered the box.

[Proffs]

Yea, I thought as much. Pretty sure it's not a blockage as it's been housed in a shed all the time and it still does produce water whilst in gear. Sounds like I've got my Saturday sorted. Figure out how to get the lower unit off. Cheers Aussie123.

[aussie123]

Disconnect the gear linkage then remove the 4 lower bolts and the leg will drop off.

You will see the water pump housing in the leg that you removed,undo the 3 or 4 bolts to remove the top housing.

Make sure the look and remember which way the blades are bent so you can slip in the new impeller the same way.

change the impeller and put it all back together.

Make sure you get the top of the water pipe fitted back into the main pipe up inside the motor as you slip the leg back on.

Do up the 4 leg bolts and connect the gear lever and your done.

What you need to check is the stainless plate under the impeller as well as the actual plastic housing.

If that plate has wear marks and grooves in it you will need a full water pump kit.

Also check the housing for cracks.

A full kit also contains a new housing top.

[Proffs]

thanks for the heads up but I think that's for '90 up cos mine doesn't have the four bolts you initially have to undo to lower the leg, it also doesn't have the gear linkage showing. Maybe I've incorrectly ID'd my outboard.

I've watched this video which I think shows what you're describing http://youtu.be/7FKtsJzTXgM

Does that make sense to you?

[Proffs]

I'll get some pics tomorrow if that helps.

[aussie123]

thanks for the heads up but I think that's for '90 up cos mine doesn't have the four bolts you initially have to undo to lower the leg, it also doesn't have the gear linkage showing. Maybe I've incorrectly ID'd my outboard.

I've watched this video which I think shows what you're describing http://youtu.be/7FKtsJzTXgM

Does that make sense to you?

You will have 4 bolts in the lower leg and some do have the 5th bolt like in that video.

Also there is various connection methods for the shift lever shaft.

Some are threaded like that,some have a pin to remove.

Also some disconnect in that spot in the vid and some disconnect inside the cowling from the end of the gear lever itself.

You just need to look at the various options to see what your motor has but what I described above is the basics of removing a lower leg unit and replacing an impeller.

[Bi_polar]

If your at all unsure, i can give you a copy of an electronic workshop manual.

PM me if you need one

[Proffs]

Ok guys, I've got some pics.

That's the donk.

Serial Number

Where I found it.

This is what I'm talking about how the gear linkage isn't shown. I'm presuming I'll have to disconnect it up the top, in the cowling.

Cheers for your help guys!

[aussie123]

Look in this entire area

[Proffs]

Think I've worked it out now. I won't need to disconnect the gear linkage as it doesn't actually move up and down when changing gears; it rotates with a spindle. So once I get the bolts off it should actually all just come out. Then just jiggle the prop to line the spindle up again when putting it back in. :cheer: