Johnson 4.0 4 hp Seahorse 2 Stroke Outboard - How To Change - Water Pump Impeller & Remove Gearbox

In this video, we have a look at how to change the impeller inside the water pump of this Johnson 4.0 4hp outboard engine.
We also look at the way the lower unit is removed.
We also found a problem that can occur when doing the impeller - being that the drive shaft can come away inside the gearbox and result in the pinion gear becoming detached.
Not only that, but we cover the repair of the gearbox in a separate video link here -
• Johnson 4.0 4 hp Seaho...

[@robertharrigan6210]

What does the gear leaver line up with when putting back together

[@MarineEngineServicing]

It slots into a hole in the gearbox. Not retained by a bolt etc.
As it’s only a fwd / neutral drive it doesn’t need retaining to “pull” a gear up.

[@Bobbybbops]

My 1984 4hp seahorse is alot different

[@MarineEngineServicing]

I believe they made the 4hp from about 1987 to 2001, in that production run there may well have been a few changes made over those years.