1980 70 HP Johnson - Remove Lower Unit - Replace Water Pump

[jhendery]

I have the mounting bolts removed 4 + 1 above the prop.

I understand the shift linkage needs to be disconnected. The screw can be found below the carb? After that I should be able to separate the lower unit from the shaft?

 

[racerone]

Re: 1980 70 HP Johnson - Remove Lower Unit - Replace Water Pump

There is one hidden screw under the trim tab.

 

[jhendery]

Re: 1980 70 HP Johnson - Remove Lower Unit - Replace Water Pump

There is one hidden screw under the trim tab.

Thanks Racer.

is the trim tab screw on the exterior? does the shift linkage need to be disconnected? how?

 

[racerone]

Re: 1980 70 HP Johnson - Remove Lower Unit - Replace Water Pump

There is a screw that you can see to remove the trim tab.-----------Then you will find one more screw hidden now as stated before. The shift rod needs to be disconnected near the lower carburetor / under the starter,----7/16 " socket required for that.

 

[Bosunsmate]

Re: 1980 70 HP Johnson - Remove Lower Unit - Replace Water Pump

Be careful to not turn shift shaft after you drop LU. Look at the way its pointing at the top for ease of reinstallment

 

[jhendery]

Re: 1980 70 HP Johnson - Remove Lower Unit - Replace Water Pump

There is a screw that you can see to remove the trim tab.-----------Then you will find one more screw hidden now as stated before. The shift rod needs to be disconnected near the lower carburetor / under the starter,----7/16 " socket required for that.

Thanks Racer.

Both trim tab bolts are removed.

Now I just need to disconnect the shift linkage. But not completely sure where to disconnect. I looked on the starboard side near the bottom of the third carb but couldn't find the 7/16".

In the pic below I circled what I think is the shift linkage. Close?

 

[racerone]

Re: 1980 70 HP Johnson - Remove Lower Unit - Replace Water Pump

You are looking on the wrong side of the motor !!!!!----As posted you need to look under the electric starter !!!---One wee bolt to take out 7/16" wrench I think.

 

[Daviet]

Re: 1980 70 HP Johnson - Remove Lower Unit - Replace Water Pump

Take a look at #69 below, maybe it will help.
:: iShopMarine.com ::

 

[jhendery]

Re: 1980 70 HP Johnson - Remove Lower Unit - Replace Water Pump

Here's a pic of what I think is the shift linkage.

On the port side below the starter at the bottom near the 3rd carb.

There are two bolts - one is 7/16 and the other not sure.

Is the bolt that needs to be removed on the bottom or viewed on the left side in the picture?

 

[Daviet]

Re: 1980 70 HP Johnson - Remove Lower Unit - Replace Water Pump

Did you look at the site in post #8?

 

[jhendery]

Re: 1980 70 HP Johnson - Remove Lower Unit - Replace Water Pump

Did you look at the site in post #8?

Will need to try again using notebook. Hard to see using bb.

It appears there is a cable attached to the clamp. Is that what connects to lower end to change gears?

 

[racerone]

Re: 1980 70 HP Johnson - Remove Lower Unit - Replace Water Pump

The bolt on the right is the one that needs to be removed.--Easiest one to get at !!!

 

[jhendery]

Got the impeller removed. Going to buy a new one. Really don't think I need the kit - just the impeller.

Putting everything back together ... Is there anything specific I need to address before re-assembly? Do the shafts need grease - should anything else be cleaned.

Or just re-assemble and good to go?

 

[BonairII]

Make sure the impeller key is there. I grease the inside of the impeller housing....makes getting the impeller in there easier. Make sure the fins are bent the correct direction when putting the impeller in the housing.

Check the water pump housing gasket(assuming that your motor calls for a gasket)...if it's bad you can grab some generic gasket material locally and make your own. Make sure the O-ring is present on the drive shaft. Its in a groove near the top of the shaft.

 

[jhendery]

Make sure the impeller key is there. I grease the inside of the impeller housing....makes getting the impeller in there easier. Make sure the fins are bent the correct direction when putting the impeller in the housing.

Check the water pump housing gasket(assuming that your motor calls for a gasket)...if it's bad you can grab some generic gasket material locally and make your own. Make sure the O-ring is present on the drive shaft. Its in a groove near the top of the shaft.

Thanks Bonair.

Removed all the parts and cleaned them up.

Need the gasket that goes below the plate and the o-ring that fits on the drive shaft.

Also need to pickup grease and OMC gasket sealing compound.

Here are the parts cleaned up.

 

[racerone]

The plate is installed.----The key is put on the driveshaft and then the impeller.--Now confirm that key is driving the impeller.---Now lower the housing down and turn driveshaft the way the motor turns it.---Push down on the housing and the impeller will be in the right way.

 

[jhendery]

Thanks Racer.

In the YouTube video they use OMC gasket sealant to re-install the rubber seals. I think the sealant helps hold the seal in place. I haven't been able to find a retail product instead of the OMC product.

I did find a gasket maker/sealant product but I don't this is intended for the same application? Maybe I am over thinking this one?

The seal I am referring to is the rubber seal used at the base of the impeller housing.

Suggestions?

 

[Bosunsmate]

you dont need to put sealant there, i use a bit of thin grease just to hold the seal in while i put the housing back on

 

[jhendery]

Thanks Bosunsmate.

Is it ok to use grease for the o-ring and other rubber seal/tubes? They are displayed on the container lid in the picture below. So sealant isn't required?

 

[jhendery]

Just realized I am missing the water pump gasket. The gasket is installed on the perimeter surface area of the water pump. Then the plate goes over the gasket.

Didn't think I needed the gasket since it was not there when the parts were unassembled.

The youtube video shows the gasket and mentions to use gasket sealant on both sides for installation.

- do I need gasket?
- do I need sealant?

And here are the pieces that need to be installed.



Have a good one eh!