Water pump rebuild kit question

[Ron Klimes]

My 1996 Johnson Seahorse 4 hp is essentially new. It has been in a barn for the last 17 years. One of my uncles owned it and sold it to my other uncle and he gave it to me. So I know for a fact it has not been ran. I have been told that I should replace the impeller in the water pump. I ordered a pump kit # 431785 to replace the old one.
I started to look at the contents and there is a O ring in a small envelope with the impeller key. I can not this O ring find in my repair book, or on line in the parts diagram. The outside diameter is is about .438 and the inside is about .309
Like I said I can't find this O ring in the book or diagrams. Does anyone know where it goes? Thanks

 

[racerone]

All you would really need is a new impeller and not a complete waterpump kit.--------If there is a groove at the top of the driveshaft the o-ring may fit there.----------Keeps grease on the spline and water out of the joint.

 

[haffiman37]

Unless it is the O-ring on top of the drive shaft. Some kits have it included.

 

[Ron Klimes]

All you would really need is a new impeller and not a complete waterpump kit.--------If there is a groove at the top of the driveshaft the o-ring may fit there.----------Keeps grease on the spline and water out of the joint.

The shop manual I have says to remove the propeller and hub. Why do I need to remove them?

 

[Ron Klimes]

Thanks.

 

[haffiman37]

Prop (and hub) should be removed from time to time to lubricate the shaft and check the drive pin.

 

[Ron Klimes]

This motor only has about 6 hours on it. With that in mind do I need to take off the prop and hub to replace the impeller? Thanks, Ron

 

[haffiman37]

Technically - no. However dip it in salt water for 5 minutes, leave it in a barn for 17 years - things might get stuck!

 

[Ron Klimes]

This motor was my Uncles and he had never used it. It still had the hang tags on it. Ron

 

[guyjg]

If the impeller is dry rotted from sitting for years it will fall apart when you run it. Better to change it.

 

[Ron Klimes]

That is the plan. I have a pump kit now and I was waiting for some OMC gasket sealing compound. After reading the comments above I am thinking I will only replace the impeller and water tube seal. Ron

 

[guyjg]

Before you crank it be sure to spray some engine fogging oil into the carbs while cranking it. The become has become dry and needs the lube before lighting it.

 

[Ron Klimes]

I have had it running. I have been using 25-1 mix as the manual says and I have ran it about 6 hours maybe a little more. It appears to have a good stream of water but like a lot of guys have told me replace the impeller. So I am going to replace it I hope next weekend. I don't plan to use it again until I get the impeller changed. It runs super good.

 

[jb3b]

I have had it running. I have been using 25-1 mix as the manual says and I have ran it about 6 hours maybe a little more. It appears to have a good stream of water but like a lot of guys have told me replace the impeller. So I am going to replace it I hope next weekend. I don't plan to use it again until I get the impeller changed. It runs super good.

I have just installed a water pump kit on my 40 hp johnson. It came with a shaft size o ring that fit in a recess in the impeller on the side that faces down. Slide it down over the shaft until it rest on top of the plate, install the cam then slide the propeller down over the cam allowing the o ring to slip in the recess of the impeller. lightly grease or oil the plate before starting to reduce the friction of the o ring and the impeller on the plate.