1975 70 hp impeller change out

Hello,

I bought a 1975 70 hp Johnson outboard last year. I changed out most of the ignition parts and she starts just fine....now.
It ran fine with no temp issues. Getting the old 'toon to go back in the water and I thought I'd better change out the water pump impeller. The guy I bought it from said he did just before he sold it to me, but I just don't trust him. So I plan to change the impeller.

The model No. is 70ESL75E. Now some questions;

1) How can I tell if I have a Hydraulic assist shift?? Yes the shift link drops down under the rear of the bottom carb. I have a SELOC repair manual it's showing the date and hp as it would be.
2) The shift link needs to be disconnected to drop the lower unit. But man it's way under there. Hard to see what exactly you do to disconnect the link. I see some sort of clevis on a shaft that extends from the shift cable.
3) Can I get a kit that has all the gaskets and seals?

any help would be appreciated.

Patrick T

Re: 1975 70 hp impeller change out

Paddy60 said:

Hello,

I bought a 1975 70 hp Johnson outboard last year. I changed out most of the ignition parts and she starts just fine....now.
It ran fine with no temp issues. Getting the old 'toon to go back in the water and I thought I'd better change out the water pump impeller. The guy I bought it from said he did just before he sold it to me, but I just don't trust him. So I plan to change the impeller.

The model No. is 70ESL75E. Now some questions;

1) How can I tell if I have a Hydraulic assist shift?? Yes the shift link drops down under the rear of the bottom carb. I have a SELOC repair manual it's showing the date and hp as it would be.
2) The shift link needs to be disconnected to drop the lower unit. But man it's way under there. Hard to see what exactly you do to disconnect the link. I see some sort of clevis on a shaft that extends from the shift cable.
3) Can I get a kit that has all the gaskets and seals?

any help would be appreciated.

Patrick T

Click to expand...

I just bought the same motor ('Rude); leg wasn't dropped in 20 years. The "E" means that you have the mechanical shift version ("B" which is what I have is the hydraulic-assist).

Yes, that shift connecter is really tucked in there but you have to disconnect it to drop the leg; you're aiming for the connection right above the rubber grommet.

You can get a water pump kit that has everything you need for the water pump change.

However if you intend on resealing the LU (which i'm currently doing), get a factory service manual. I couldn't find a seal kit so I had to purchase the components separately (4 bearing carrier bolt o-rings, bearing carrier o-ring, shift housing o-ring, shift housing gasket, driveshaft bearing carrier o-ring, back-to-back driveshaft seals and back-to-back prop-shaft seals).

Re: 1975 70 hp impeller change out

You're removing bolt #55 to disconnect the shift linkage.

Also, you can see part #5 is a bearing carrier in your model. If you look at the "B" version, it's an oil pump.

Hope that helps. good luck!!

Re: 1975 70 hp impeller change out

Blue fin,

Thanks. Your link of part #55 did not open. But to understand better, you remove the small bolt completely or just loosen? Is the rod just have a flat that is pinched? Looks like removing the battery cable, fuel line will open things up a bit for a better view!

The lower end seals appear to be fine. We have a slip and the motor sat in the water all season. When I drained the lower end gear oil it looked new. No water and still clean.

Patrick T

Re: 1975 70 hp impeller change out

It's going to have to come out:


Also, it would be prudent to make a shift-rod height gauge once you drop it; the height of this rod is critical for the function of your motor.

Re: 1975 70 hp impeller change out

Bluefin16,

Thank you for your guidance. It all came apart without any issues. Once I pulled back the fuel pump and the ground cable, the shift connection became clear. Other than one hidden bolt under the round cover, she slid apart without much of a tug. What is the concern about the shift rod height gage? Does it change height is it rotates?

The impeller looks fine but I'm replacing it to be sure. The o-ring at the top of the drive shaft fell apart as it was coming off. I'll be getting a water pump kit ordered on Monday.

Have you replaced your rectifier? They can take out a power pack and are real cheep. As I said above, I replaced most of the parts.

I saw this non running motor on Craigs list. With the ignition, Replaced fuel system as well, all new hoses, carb rebuild and fuel pump rebuild. Started first crank. That's got to make you feel good

Patrick T

Re: 1975 70 hp impeller change out

Np Patrick! glad that i could help!! Awesome deal on bringing this bad boy back to life!! She'll live to fight another 40 years!!

Exactly, if you inadvertently rotate the shift rod, it will be at the incorrect height putting the gearcase & shift lever out-of-sync.

What prompted you to change the rectifier?

Re: 1975 70 hp impeller change out

Bluefin,

Glad to hear if rod rotates I just have to adjust the shift cable. It should be OK. Regarding the rectifier; As stated above, I bought the motor as non running. Here on this site there is a good ignition diagnostic plan. One thing I recall was reading a shorted rectifier can kill other much more expensive components. My wires on the rectifier were iffy at best so I replaced it. Then decided to just replace the cracked coils and power pack.

Maybe best for another thread but I had good luck buying a Craigs list boat and motor. I'm guessing an old non running fiberglass boat of the '70s are not to appealing. I think many are intimidated by two issue; "what do I do with the old boat? and it does not start." I checked the compression and it was good. Rebuilding the fuel system and ignition system was about $300 as I recall. Our local dump takes old boats for $25. With such good luck on the first one, I'm going to start looking for another

Patrick T