removing lower unit 1975 Johnson 50hp

[Hrokor]

Going to attempt to replace the impeller on a 1975 Johnson 50hp (50esl75b) and was told about four bolts which I see and a fifth one near the carburetor which I cannot locate. Can anyone help direct me to the exact location and maybe the size of the bolt that I need to remove?

 

[Joe Reeves]

Re: removing lower unit 1975 Johnson 50hp

Look closely under the hood pan to locate the (approx) 1/4" dia shift rod. Okay, now on top of the pan, under the carburetor area, you'll see the shift linkage.... look closely on the port (left) side and you'll see a horizontal bolt going thru the side of that linkage... a long shoulder type bolt with a 7/16" hex head. Remove that bolt to disconnect the shift rod.

Now, remove the "Trim Tab" to see if there's a bolt under there.

 

[Hrokor]

Re: removing lower unit 1975 Johnson 50hp

Thanks, Joe! I found it and replaced the impeller and housing. Now when I tried to turn it over the starter doesnt' engage the flywheel..grrrr

 

[Joe Reeves]

Re: removing lower unit 1975 Johnson 50hp

Causes.... Bad battery, loose cable, tight cable but dirty connection. Remove, clean, all cable terminals and components they connect to. Any of this results in a voltage drop.

Check starter with jumper cables directly to starter.

 

[DJ]

Re: removing lower unit 1975 Johnson 50hp

Thanks, Joe! I found it and replaced the impeller and housing. Now when I tried to turn it over the starter doesnt' engage the flywheel..grrrr

Two things.

1. Remove and clean the negative battery terminal from the engine block.

2. BATTERY DISCONNECTED. With your fingers, walk the starter pinion gear up the shaft. You can do this by rotating it the reverse direction of rotation. While the pinion gear is in the up position, lubricate the shaft with a very light coat of lithium grease.

 

[Hrokor]

Re: removing lower unit 1975 Johnson 50hp

Thank you DJ, I will do that right now. Was wondering if I could have done something wrong during the installation of new impeller/housing? Will repost after I do what you suggested.

 

[Hrokor]

Re: Starter Trouble 1975 Johnson 50hp

Re: Starter Trouble 1975 Johnson 50hp

DJ, tried that and get same results. Gear shoot up to flywheel the shaft just spins.

 

[DJ]

Re: Starer Trouble 1975 Johnson 50hp

Re: Starer Trouble 1975 Johnson 50hp

If the gear engages the flywheel and the starter shaft just spins, then you have a starter drive problem. There is a one way clutch in that starter drive.

 

[Hrokor]

Re: Starer Trouble 1975 Johnson 50hp

Re: Starer Trouble 1975 Johnson 50hp

So does that mean the starter is shot? It was working fine before the impeller replacement. hmmm

 

[Joe Reeves]

Re: Starer Trouble 1975 Johnson 50hp

Re: Starer Trouble 1975 Johnson 50hp

If the starter armature shaft is spinning within the bendix gear, that means that the bendix gear requires replacing.

If a Prestolite starter, bendix gear is part number 384785. Unfortunately this gear is no longer available since 1990 ($60.00 at that time).

If a Bosch starter, the bendix gear is part number 384781 ($31.63 in 2010), still available.