replacing impeller on 4hp johnson

[willf]

I have a 1969 4hp Johnson that needs the impeller replaced, or so I am told. My question is, since I have never replaced one, is this fairly straight forward or is it a "can of worms." I don't have access to a manual at the moment so I have no idea how complicated these small outboards are.

regards,

willf

 

[HighTrim]

Re: replacing impeller on 4hp johnson

Fairly easy job if youre somewhat mechanically inclined and have a few tools. A manual helps, but we can talk you through it no problem. Youll need some adhesive or gasket sealing compound for impeller housing, plate and screws, oil for the impeller blades. GL

 

[F_R]

Re: replacing impeller on 4hp johnson

Easy job. One hint though: If it is a weedless drive, don't pull the drive shaft out of the lower unit. The pinion gear falls off the end if you do, and you will have a heck of a time getting it back in. Actually, that is simple too. You just have to hold the gearcase in a certain position.

 

[willf]

Re: replacing impeller on 4hp johnson

First of all, thanks for responding to my question. Right now I am just looking at the engine. I cannot tell if it is weedless although it doesn't appear to be so. I have lots of tools so that should not be a problem. I see four screws that appear to hold the lower unit onto the upper unit. If I remove the screws, will the lower unit slid downward or will parts start to drop out, i.e., like bearings, etc.

Like I said, I have never worked on an outboard, however, I did build my own bi-plane from plans and flew it for several years.

 

[F_R]

Re: replacing impeller on 4hp johnson

Remove the four bolts and the lower unit will slide down and out. You may have to twist it gently back and forth a bit as you pull to loosen it's grip between the water tube and rubber grommet. nothing will jump out and get you. Actually, it's very simple.

The weedless LU and propeller angles downward. The Right Angle drive points straight back.

 

[willf]

Re: replacing impeller on 4hp johnson

OK, so far so good. I removed the four lower bolts and pulled the lower unit down and out. There was no gasket or gasket material on the unit but a few drops of water from testing inside. It was also lots of surface rust but no pitting, nor any kind of lubricant on the shaft.
I now see two screws on the lower unit. Shall I remove them?

Regards,

will

 

[F_R]

Re: replacing impeller on 4hp johnson

Yep, that's the water pump.

 

[Scaaty]

Re: replacing impeller on 4hp johnson

Here ya go...(even if Weedless (angled down prop and shaft), probably the same)
Simple operation..

 

[willf]

Re: replacing impeller on 4hp johnson

Wow, that was a terrific ego booster!! It was a lot more simple than I expected, thanks to all your help. After the dis-assembly and inspection, I reassembled everything which was pretty easy with the exploded diagram that you sent. The impeller was ok, in one piece and quite flexible. Again thanks for making my task easy.

Regards,

Will

 

[Scaaty]

Re: replacing impeller on 4hp johnson

Glad things went well...!