Help with changing impellor in Johnson 5hp 2T outboard

[Reptile Smile]

Hi all,

Had a bit of a bad one with an engine that's new to me. Was leaving Bristol Entrance Lock with this outboard pushing a Hurley 24/70. I was aware that the cooling stream wasn't much - sometimes a minor dribble, and sometimes just a few drops. The engine cut out just as I left, and I assumed it had overheated. The harbourmaster threw me a line, and there was a resulting scramble which resulted in success. Later, though, I found the fuel line wasn't connected. What I don't know was whether it had overheated (it started again shortly afterwards, and I used it to get back to my berth) or whether it just didn't have fuel, and I'd accidentally knocked the fuel line off and it was running off fuel in the carb bowl.

In any event, I've sold the boat and am selling the engine. I have a spare impellor but have never done this in an outboard. I presume it's in the lower section of the leg. Is this right? As opposed to being on the head section of the engine?

If so, could anyone look at the following pics and suggest what I should be doing? I've highlighted some likely looking bolts...

Note that B is the same as C, and E is where the cooling water exits the head.

Cheers all

 

[duncan99210]

Looking at this exploded parts diagram http://www.boats.net/parts/search/BRP/JOHNSON/1998/BJ5FRBLECC/GEARCASE/parts.html I'd reckon that bolts A, B and C will release the gear casing and extension. That'll let you remove the gearcase then undo bolt D to remove the extension and give access to the water pump.

 

[MoodySabre]

I changed the impeller in my Johnson 3.5 last year. The SS bolts were seized in the ali casing and broke off. I then had to drill one out without damaging the thread. A right PITA.
If you are not going to use it then sell as it is and add a spare impeller as a bonus!

 

[VicS]

Hi all,

Had a bit of a bad one with an engine that's new to me. Was leaving Bristol Entrance Lock with this outboard pushing a Hurley 24/70. I was aware that the cooling stream wasn't much - sometimes a minor dribble, and sometimes just a few drops. The engine cut out just as I left, and I assumed it had overheated. The harbourmaster threw me a line, and there was a resulting scramble which resulted in success. Later, though, I found the fuel line wasn't connected. What I don't know was whether it had overheated (it started again shortly afterwards, and I used it to get back to my berth) or whether it just didn't have fuel, and I'd accidentally knocked the fuel line off and it was running off fuel in the carb bowl.

In any event, I've sold the boat and am selling the engine. I have a spare impellor but have never done this in an outboard. I presume it's in the lower section of the leg. Is this right? As opposed to being on the head section of the engine?

If so, could anyone look at the following pics and suggest what I should be doing? I've highlighted some likely looking bolts...





Cheers all

You dont tell us the year, they vary a bit, or preferably the Model number from the plate on the transom clamp bracket. That will identify the exact model and the year.


First thing to do is to check that the tell tale is not blocked. Take care with the elbow marked "E", it is plastic.

If you do want to continue to replace the impeller the bolts you have marked are the ones to undo.

But check the gear oil first as during this work is the time to fit all new seals to the gearcase if there is any sign of water ingress ...... these gearboxes do not appreciate seawater in them!

It is a long shaft model in which the drive shaft passes through a bush in the 5" extension. I find it best to remove the long bolt "A" and the two bolts "C", remove the lower unit complete with extension and clean the vertical drive shaft before removing the two bolts next to the anode "D" and removing the extension( when rebuilding fit the extension to the exhaust housing first, then the gear case assembly)

Take care when removing these bolts as you do not want to break any of them!

The gearcase should come off complete with drive shaft and gear shift shaft leaving the water tube insitu. Watch out for an O ring which may be fitted in the groove below the drive shaft splines. Depending on year model they may or may not be one but refit one if there is one as it will form a seal at the top to keep water out of the splines.

Once the gear case assembly is separated and extension removed you will see the water pump which can be unbolted and slid off up the drive shaft ( take care not to pull the drive shaft out of the gear case .. It is not retained but doing so could damage the seals below the pump.) Watch out for the impeller drive key/ pin as you remove the impeller.

With a hose check that you can get a good flow up the water tube and through the engine and telltale as there could be a problem with the grommet at the top of the water tube blocking the flow. A stut wire poked up the water tube should hit something solid at the top. If it hits something that feels rubbery the grommet needs replacing. that means also separating the power head from the exhaust housing! No rocket science but it's all work!

Ideally be prepared to renew the gaskets either side of the water pump bottom plate but with care you may not damage the existing ones ( I have always been able to reuse them), Also inspect/ replace the water tube grommet in the pump housing.

The parts diagrams on the BRP parts website http://epc.brp.com/Index.aspx?lang=E&s1=1261c7cc-f9f5-44e5-a1ab-ce1fc33aa4ff or on the Boats.net website, http://www.boats.net/parts/search/BRP/JOHNSON/parts.html may be helpful but look at the diagrams for the corresponding year model for 6 HP if no 5 HP model is listed.

You should also find the motor is covered by the manual at http://boatinfo.no/lib/library.html

BTW I buy parts from Oakley Marine in Brighton, http://www.outboards-direct.co.uk/ but forumites in the past have had good service from Wills Marine in Kingsbridge, http://www.willsmarine.co.uk/

 

[William_H]

I write as if it is like the 6HP in general terms. Vic's description is really good. Just to add once you get the bolts out you can get about 2cms of movement before the gear shift rod has to be disconnected. As you pull the handle will move to push rod down and gear box rod will pull up into gear. There is a clamp bolt 3/8 AF I think which when removed allows the rods to disconnect. The next problem that sometimes arises is that the drive shaft spline will not disconnect. Rotation of the engine can sometimes release the shaft. Once removed as Vic says pump housing is clear.
Do be careful with the ss bolts into ali as they will seize up and snap off so easily. Heat and lubricant are your best bets.
Do check with a garden hose up the water pump pipe that feeds to the engine. I have had more trouble with blockage here than of pump failure. Strangely my 6HP oz engine is radically different to Vic's European engine but still prone to blockage.
Getting it all back together is a real trick. You must guide the water pipe into the pump outlet the gear shift rods together and the drive shaft into the spline almost all at once. The refit the bolts with duralac or lots of grease. good luck olewill

 

[VicS]

I write as if it is like the 6HP in general terms. Vic's description is really good. Just to add once you get the bolts out you can get about 2cms of movement before the gear shift rod has to be disconnected. As you pull the handle will move to push rod down and gear box rod will pull up into gear. There is a clamp bolt 3/8 AF I think which when removed allows the rods to disconnect. The next problem that sometimes arises is that the drive shaft spline will not disconnect. Rotation of the engine can sometimes release the shaft. Once removed as Vic says pump housing is clear.
Do be careful with the ss bolts into ali as they will seize up and snap off so easily. Heat and lubricant are your best bets.
Do check with a garden hose up the water pump pipe that feeds to the engine. I have had more trouble with blockage here than of pump failure. Strangely my 6HP oz engine is radically different to Vic's European engine but still prone to blockage.
Getting it all back together is a real trick. You must guide the water pipe into the pump outlet the gear shift rods together and the drive shaft into the spline almost all at once. The refit the bolts with duralac or lots of grease. good luck olewill

Your description of the gearshift is of an earlier model than that shown.

I am sure from what can be seen in the photos that this one dates from between 1980 and 1999 and most likely made in Belgium.

The shift mechanism changed in 1980 from a push/pull system with the two part shift rod you describe to single piece shift rod which rotates to change the gear.

If I am right the shift rod is retained in the gearbox and simply pulls from the mechanism at the top. There is no clamp between two parts to worry about although reassembly is made a bit more of a fiddle because water tube, shift rod and drive shaft all have to be more or less simultaneously correctly aligned.

If we were told the model number, or even just the year of manufacture we could be 100% sure about things.

 

[crispyone]

first port of call for me is always Google - there are several YouTube videos showing how to do it on my 1986 4HP 2T Evinrude. Very straightforward.