Johnson 1979, 85 Hp. Need help for changing water pump.

[Dima2004]

My boat is overheating when its just idling more than 4 minutes. But when I am driving its seems to be working okay. This is my first boat and I am trying to change the water pump. I ordered the water pump kit at napa for 80$. I am trying to take the lower unit off. I have taken off all the bolts and crews on the bottom. But for some reason it wont come off? Thank you!

 

[wilde1j]

Re: Johnson 1979, 85 Hp. Need help for changing water pump.

Shift rod needs to be disconnected under bottom carb. There's also a bolt under the trim tab.

See here also:
http://forums.iboats.com/showthread.php?t=309188

 

[Dima2004]

Re: Johnson 1979, 85 Hp. Need help for changing water pump.

I think i have disconected the rods, I attached the picture. The back part of the lower unit seems to come off just a little, like few mm. but the front doesnt move at all, like there is another bolt but I cant find it?

 

[ezeke]

Re: Johnson 1979, 85 Hp. Need help for changing water pump.

Seven screws from the bottom - one is holding the trim tab and that's hiding one above the trim tab that has to come out.

You have disconnected the control cables. The shiift rod is in the center under the carbs.

You will need to remove the pin that holds the shift rod. It is unscrewed from the starboard side. See the diagram #66 by clicking the thumbnail twice.

 

[Dima2004]

Re: Johnson 1979, 85 Hp. Need help for changing water pump.

Thank you very much for help. I am having a little trouble finding the pin, to disconect the shift rod. Is this the pin?

 

[ezeke]

Re: Johnson 1979, 85 Hp. Need help for changing water pump.

It's a slotted screw with an elongated nose. It's almost in the middle of the pan, just before the shift rod, near the bottom. The head is facing you when you look from the starboard side.

 

[Dima2004]

Re: Johnson 1979, 85 Hp. Need help for changing water pump.

Okay i unscrewed that slotted screw lower unit came off. I replaced the water pump it wasnt that hard. Now i have trouble putting it back up. I cant really connect the shift rod back. Help please?

 

[Dima2004]

Re: Johnson 1979, 85 Hp. Need help for changing water pump.

Problem with alining the shift rod pin and the hole. any advise?

 

[ezeke]

Re: Johnson 1979, 85 Hp. Need help for changing water pump.

Pull the shift rod up so that it is in forward, that will make the best target.

Have the offset facing forward.

If you turned the shift rod, reset the height now or you will need to do it again. The height should be 21.834" from the mating surface of the gearcase to the center of the hole at the top of the shift rod with the gearcase in NEUTRAL.

If you have some long nosed vice grips, you may be able to hold the shift rod from under the cowling to keep it from turning while you line up the pin.

 

[kenmyfam]

Re: Johnson 1979, 85 Hp. Need help for changing water pump.

2 person job. Take the plugs out and have someone rotate the flywheel a little till the drive shaft splines line up. Make certain that the water tube goes in to the water pump. When you are close, put 1 bolt in a few threads and have someone move the control a little at a time. While they are doing this you need to align the shift rod while giving them direction as to which way to move and how much. It is possible to do it alone (I did 3 alone today as my son is working elsewhere) but much easier with a helper. Some folk find it easier with the carb's off to get better access. Use a long screwdriver or similar to align it.
Good Luck and let us all know how you make out.
Bottom line is, do not force anything or bad things will happen.

 

[ezeke]

Re: Johnson 1979, 85 Hp. Need help for changing water pump.

Are we having fun yet?

 

[Dima2004]

Re: Johnson 1979, 85 Hp. Need help for changing water pump.

Thank you for telling me to adjust the height to 21.834". Yes, i am still trying haha

 

[Dima2004]

Re: Johnson 1979, 85 Hp. Need help for changing water pump.

In what gear should i have the lower unit in? i try forward, and when i slide the lower unit into the upper unit, it snaps into nutreal. but the reverse gear is too low?

 

[Dima2004]

Re: Johnson 1979, 85 Hp. Need help for changing water pump.

Okay! I got it all together . All gears working! Took one day to change the water pump. Working together with my dad, our first boat and motor. Thank you very much Ezeke, Kenmyfam and Wilde1j.

One more question. I took all the gear oil out, what kind should I pour back in? Its 1979 Johnson, 85 hp. Model# 85ML79R.

 

[TD_Maker]

Re: Johnson 1979, 85 Hp. Need help for changing water pump.

Go to Walmart and pick up a quart of the Pennzoil or Lubrimatic Lower Unit 90 Wt. gear oil (I can't remember the exact capacity) Anyway, pick up one of those hand pumps that attach to the bottle opening. This will make the job MUCH easier. Remember, the lower unit must be filled from the BOTTOM screw hole to avoid air pockets. Fill the unit slowly until the new fluid starts to flow out the top hole. Replace the top hole screw, for this will prevent the fluid from flowing out of the bottom hole until you can get that screw in. Replace the nylon screw seals. Dont try to reuse them.

 

[kenmyfam]

Re: Johnson 1979, 85 Hp. Need help for changing water pump.

I always use the Mercury high performance gear lube. Don't know if it is any better or worse than other ones but I have seen it in a lower unit that had been leaking for a while and it had still maintained a lot of lubricity even while mixed with the water.
Just my 2 cents though.