2 antiques

I am an auto technician with 54 yrs + exp.I was out fishing last weekend when my 1957 5.5 johnson quit.I imediatly noticed smoke from the motor.I pulled the cowling off and realized it was overheated.I waited 1 hr. and restarted it on the first pull (as ussual).I ran it for 2 minutes and shut it down with no problems.I repeated this several times until I made it back to the dock.I noticed it was no longer spitting water.My next step is to replace the water pump .Having no experience with lower units or water pumps,I am looking for help. any input is greatly appriciated

Re: 2 antiques

Because of your long experience as a wrench I am sure you understand why we always recommend a factory Service Manual, JD.

Try www.kencook.com or www.outboardbooks.com.

Good luck.

Re: 2 antiques

It's a pretty easy job, but on your particular motor, you have to take the powerhead off of the leg in order to disconnect the shift linkage. Other OMC's have a little access port on the side of the leg for this, but yours doesn't. There are 4 bolts at the water pump housing (the bulge up above the anti-ventilation plate), and after the shift linkage is disconnected up top, it will drop straight down. You'll be looking at the lower unit with the driveshaft and shift linkage sticking out. The pump housing is right on top, with three or four small screws. If you're on salt water, good luck! There's a very small dowel pin in the shaft that drives the impeller which disappears rather easily if you drop it. The trickiest part of putting it back together is making sure the water pipe goes into the grommet on the top of the water pump. It WILL go together with the pipe out of place, but it won't pump. At the minimum, you'll need the gasket for the powerhead/leg connection, and an impeller. Depending on how old it is, and your local conditions, you may need a new pump housing as well. It's often a good idea to replace the grommet for the water pipe in the pump housing as well. Most OMC's have an O-ring right below the upper spline on the drive shaft- on most old ones, it's dried up or missing. It helps keep stray water out of the spline in the end of the crankshaft.

Re: 2 antiques

MushCreek said:

It's a pretty easy job, but on your particular motor, you have to take the powerhead off of the leg in order to disconnect the shift linkage. Other OMC's have a little access port on the side of the leg for this, but yours doesn't. There are 4 bolts at the water pump housing (the bulge up above the anti-ventilation plate), and after the shift linkage is disconnected up top, it will drop straight down. You'll be looking at the lower unit with the driveshaft and shift linkage sticking out. The pump housing is right on top, with three or four small screws. If you're on salt water, good luck! There's a very small dowel pin in the shaft that drives the impeller which disappears rather easily if you drop it. The trickiest part of putting it back together is making sure the water pipe goes into the grommet on the top of the water pump. It WILL go together with the pipe out of place, but it won't pump. At the minimum, you'll need the gasket for the powerhead/leg connection, and an impeller. Depending on how old it is, and your local conditions, you may need a new pump housing as well. It's often a good idea to replace the grommet for the water pipe in the pump housing as well. Most OMC's have an O-ring right below the upper spline on the drive shaft- on most old ones, it's dried up or missing. It helps keep stray water out of the spline in the end of the crankshaft.

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The 5.5 has a carbon seal at the top end of the drive shaft. It is vital to the long term health of the powerhead. Always make sure it is "right" and install a new 303355 gasket and 303347 o-ring. If it leaks you will eventually find a connecting rod sticking through the crankcase.

EDIT: Replace the cylinder head gasket also. It will leak after having been overheated.