1973 Johnson Outboard 4hp water coming from exhaust holes

[mbeards]

I have a 1973 Johnson 4hp, Model 4R73, that has water coming from exhaust holes when running. Is that what it is supposed to do or does it have it's own hole somewhere that i pumps water out of? Thanks, Mike

 

[Chinewalker]

Perfectly normal. It's how you know it's pumping!

 

[Vic.S]

I have a 1973 Johnson 4hp, Model 4R73, that has water coming from exhaust holes when running. Is that what it is supposed to do or does it have it's own hole somewhere that i pumps water out of? Thanks, Mike

Most of the water a leaves with most of the exhaust gas under water from the two openings you can see above the prop along the joint between the top of gear case and the bottom of the exhaust housing.

The holes you mention are there to relieve back pressure on the exhaust which might make staring difficult esp if the motor is deeply immersed. A little water being blown out from there, as Chinewalker says, confirms that the pump is pumping.
Larger, later engines usually have a separate tell tale from which a strong jet of water is ejected to confirm that the pump is pumping, but not these 4hp models

 

[racerone]

If the motor is " new to you " you should install a new impeller.---Also grease the driveshaft spline and install a new o-ring on the driveshaft.---Failure to maintain that spline joint has sent many of these motors to be recycled into beer cans.

 

[mbeards]

Perfectly normal. It's how you know it's pumping!

Thanks

 

[mbeards]

Most of the water a leaves with most of the exhaust gas under water from the two openings you can see above the prop along the joint between the top of gear case and the bottom of the exhaust housing.

The holes you mention are there to relieve back pressure on the exhaust which might make staring difficult esp if the motor is deeply immersed. A little water being blown out from there, as Chinewalker says, confirms that the pump is pumping.
Larger, later engines usually have a separate tell tale from which a strong jet of water is ejected to confirm that the pump is pumping, but not these 4hp models

Thanks, Is the impellar supposed to be made of rubber and you have to fold down the ends somewhat to make it fit in the housing? Mike

 

[mbeards]

If the motor is " new to you " you should install a new impeller.---Also grease the driveshaft spline and install a new o-ring on the driveshaft.---Failure to maintain that spline joint has sent many of these motors to be recycled into beer cans.

Where exactly does the o-ring go? Mine was way down the shaft just sitting on top of the impeller housing. Mike

 

[racerone]

There is a groove just below the spline.----Make sure you get the correct o-ring !

 

[steelespike]

When greasing the spline; just enough grease to protect the spline.
Too much grease and the shaft won't slide in.

 

[hardwater fisherman]

Thanks, Is the impellar supposed to be made of rubber and you have to fold down the ends somewhat to make it fit in the housing? Mike

I have not done that many but the the way I found to be best. Is put the impeller on the wear plate with the key in place and while turning the driveshaft clockwise push down on the housing. Should fall into place.

 

[Vic.S]

When greasing the spline; just enough grease to protect the spline.
Too much grease and the shaft won't slide in.

No blob of grease on the end of the shaft is the crucial thing.Just grease the splines

 

[mbeards]

Thanks for all the answers. I bought a boat motor and trailer. Have had to replace hubs and bearings on trailer and rebuild carb and replace fuel pump on motor. Then found out water pump was not working. Somehow Keyway was misaligned when installed and never splined up properly with impeller. All is good... for now.