Johnson 1985 4hp Deluxe oil leak and water pump

[peterjc1]

I have a 1985 4hp deluxe that I need to replace the water pump. It stopped pumping yestrday with only a spit coming out at the top. I also have a oil leak where the lower unti connects to the shaft. I am wondering a couple of things. How do I disasemble the unit to replace the water pump and the gasket or seal? Is it a gasket or seal at the top of the lower unit? The oil leak can be sean all around the seam where it connects tot he shaft. Is there any special trick to removing and reinstalling the lower unit and water pump i.e. getting everything lined up proper;y and anything that should be avoided before taking it apart? What kind of gear oil should I use for the lower unit and how often should it be replaced? How is it filled properly? Lastly where can I get the pump, seal or gasket for a decent price and does anyone know the specific part numbers. Thanks in advance.

 

[Rick.]

Re: Johnson 1985 4hp Deluxe oil leak and water pump

I am assuming your deluxe has forward and reverse gears. To replace the water pump impeller is a fairly easy task. The seal will be a bit trickier and you should have a manual for doing it. I would suggest an OMC factory service manual. It will also tell you the procedure for the impeller. Here is a link that will show you the part breakdown for you motor. You will see in it the bolts you need to remove to get the leg off and the way the pump goes together. If you get stuck anywhere along the line, don't be afraid to ask. Some members have expressed difficulty removing the shift rod on your engine but haven't come back to say how they accomplished it. I think Iboats will have the parts you need or any OMC service center. Best of luck. Rick.
http://shop2.evinrude.com/ext/index.aspx?s1=e9a4dfad50bcbe7303216e19c7dbc524

 

[Vic.S]

Re: Johnson 1985 4hp Deluxe oil leak and water pump

If that is the model with a reverse gear you will have to look at the diagram of the 1986 models to see what it is like . They do not seem to cover the reversing gear boxes in the parts list for 1985 (Is it a Belgium made one for the European market by any chance )

Assuming it is the reversing gear box it will be easy to drop it. Just three bolts to undo and the shift rod pulls from the mechanism at the top with no disconnecting to do.
The drive shaft may be stuck in the crankshaft splines though! (Lightly grease when rebuilding)
If its a long shaft model remove the extension with the gear case , clean the drive shaft then remove the extension.

It is quite straightforward to remove the gearcase cover and change the seals. There's a gasket to renew as well.
The drive shaft is not retained in the gear case and will lift out IIRC (Might as well do the O ring on the shift rod as well while you are there)

The grommet at the top of the water tube can be troublesome so connect a hose to the water tube to be sure you can get a good flow of water through the power head. If the grommet is blocking the flow you have to remove the power-head to get to it!

BUT oil leaking from the joint between gearcase and the exhaust housing is probably only unburnt oil from the fuel. (nevertheless not a bad idea to replace the seals while you have the unit off)
Check your gearcase oil for signs of water ingress! (Milky looking = water)

If it is just the non reversing gear box I think the shift rod has to be disconnected at the top and I think that may require removal of the power head! On second thoughts I dont think its retained at the bottom so may pull out of the gear case
The seals won't be so easy to change unless you can hook them out of their housing once the pump is removed

Rebuilding is just a bit of a fiddle. Getting the shift rod into position, the water tube into the pump and the drive shaft into the crank shaft. (Turn the flywheel slowly to aid engagement of the splines)

Oil is outboard gear oil (with a viscosity of around SAE 85 or 90).

Change it every year at the end of the season or every 100 hours if sooner. Renew the washers on the fill and level plugs. Using a pump or squeezy bottle the new oil goes in the bottom hole until it flows from the top one. Reversing box holds about 325ml

The prop-shaft oil seals are the most likely to cause water ingress as they are easily damaged by fishing line. Still not difficult to change as they are in the bearing housing which simply unbolts and pulls off.

Service manual? whats that?

 

[peterjc1]

Re: Johnson 1985 4hp Deluxe oil leak and water pump

So here's another thought. Maybe based on what I've read and where we were when the motor stopped pumping I don't have a problem at all.

First is the oil leaking at the seam is unburnt 2 cycle oil then the seal isn't leaking. I will check to see if the lower unit oil is milky as suggested.

Secondly we were in a place with a shallow soft muddy bottom when the engine stopped pumping water yesterday. Is it possible the intake brought up mud and blocked the water flow. If so how can I rectify that?

Thanks again Peter

 

[peterjc1]

Re: Johnson 1985 4hp Deluxe oil leak and water pump

By the way it is manufactured in belguim and does ahve reverse and forward gears.

Here is the info off the motor:

Model - BJ4RDHCOB
Serial Number - B003970
Outboard marine Belgium NV
Brugge Belgium

 

[Rick.]

Re: Johnson 1985 4hp Deluxe oil leak and water pump

So here's another thought. Maybe based on what I've read and where we were when the motor stopped pumping I don't have a problem at all.

First is the oil leaking at the seam is unburnt 2 cycle oil then the seal isn't leaking. I will check to see if the lower unit oil is milky as suggested.

Secondly we were in a place with a shallow soft muddy bottom when the engine stopped pumping water yesterday. Is it possible the intake brought up mud and blocked the water flow. If so how can I rectify that?

Thanks again Peter

Well that is a different problem than an impeller giving up. I would try to flush it with some muffs on the leg. Muffs don't fit all that well on a 4hp so you might need some assistance but try to purge the mud before it starts to get dry or your going to be sorry. Rick.