johnson 15 hp lower end noise

[wlfman71]

I have a 1979 Johnson 15 hp short shaft. I hear and bang,bang,bang,bang,bang, noise from the lower end when I am coming to a stop.just wondering what the noise is and some advise on were to start.im very mechanicaly inclined so tell me were to go from here.
Wlfman

 

[wlfman71]

Re: johnson 15 hp lower end noise

oh I did pull the lower end off and the oil in the gear box looks normal and creamy no metal shavings.

 

[the machinist]

Re: johnson 15 hp lower end noise

Creamy? That would be an indication that there has been/is water inside. Any noise there is not common. Drain the oil all out, inspect the settlings.

The easiest & most likely cure is to replace the nylon seals UNDER both the drain & oil level plugs. Replace the oil. Run it a while & check for new creamy contaminated oil. If you get contaminated oil, you have other seals leaking, could be prop shaft, driveshaft seal under water pump or a leaky lower shifting rod seal.

If water has been in there AND allowed to set for some time, you could have rusty bearings & gears (not good).

On those motors it is not a easy job to tear apart the gearbox without special tools & then you will need a service manual on how to reassemble it.