1972 Johnson 20 shifting problem

[johnson72]

I have a 1972 johnson 20 hp model 20R72. Can anyone get me a diagram of the motor?

 

[bankerjohn]

Re: 1972 johnson diagram

Re: 1972 johnson diagram

Here's one site ...

http://www.ishopmarine.com/ishop/js...CatFilter=BRP&eCatSupFldr=supplier-100-005-EJ

 

[johnson72]

Re: 1972 johnson diagram

Re: 1972 johnson diagram

Thaks for the diagram. Something is wrong with my gears or linkage from the shifter because when i shift into forward, it stays in neutral. But reverse is fine. Does anyone have any ideas?

 

[johnson72]

1972 Johnson 20 shifting problem

I have a 1972 johnson 20 hp model 20R72. When i shift into forward, it stays in neutral but reverse works. I was leaving a bay and it popped out oof forward and into neutral, but the shifter was in forward. Can anyone help?

 

[tashasdaddy]

Re: 1972 Johnson 20 shifting problem

has the lower unit been off lately? the shift connect bolt has to go thru the indention on the shift rod.

 

[tashasdaddy]

Re: 1972 Johnson 20 shifting problem

double post only serves to confuse you and members. not appreciated on iboats.

 

[johnson72]

Re: 1972 Johnson 20 shifting problem

I dont know why it double posted here. The lower unit hasnt been off lately that i know. i bought it a few months ago but it has worked fine since i bought it until a few days ago.

 

[tashasdaddy]

Re: 1972 Johnson 20 shifting problem

take the 1x3 plate off the side of the motor leg, check the connection, the bolts must go thru the indents in the rods. if that is correct, the handle may have slipped but very doubtful. or the forward gear and clutch dogs are going out in the lower unit, not unusual, for the age of the motor.

 

[johnson72]

Re: 1972 Johnson 20 shifting problem

Reverse still works. I was leaving a bay and it just went into neautral, but there wasn't a clunk or any sound.

 

[johnson72]

Re: 1972 Johnson 20 shifting problem

What do you have to take off to get to the linkage under the carb?

 

[14ftgrumman]

Re: 1972 Johnson 20 shifting problem

Why would you want to get to the linkage under the carb? You have a shift-lower unit problem.
Follow Tashasdaddy's advice.
Remove the plate on the lower unit and make sure that the shift rod is connected properly. I've got 2 of these (1 20HP and 1 25HP) He's right on the clutch dog. I have spare everything for these.
They are very simple to work on, just get a factory manual. I've got a Sealoc, but I will find a factory manual one of these days.

 

[johnson72]

Re: 1972 Johnson 20 shifting problem

So it could be the clutch dog even though there wasn't a sound?

 

[14ftgrumman]

Re: 1972 Johnson 20 shifting problem

Yep. Clutch dog wears on the ears, it doesn't brake-usually

 

[kbait]

Re: 1972 Johnson 20 shifting problem

I had one act weird like that, and the shift fork (that actuates the lateral movement of the clutch dog) was bent and not mated to the dog correctly. I bent it back and it worked fine. Hope it's that easy for ya!

 

[johnson72]

Re: 1972 Johnson 20 shifting problem

Thanks for the advice. I will see if I can fix it this weekend.

 

[johnson72]

Re: 1972 Johnson 20 shifting problem

I fixed it. A pin behind the prop broke in half and got caught on the prop. It runs great now.

 

[johnson72]

Re: 1972 Johnson 20 shifting problem

It happened again! Does anyone know why a shear pin behind the prop would shear even though I didn't hit anything?

 

[Daviet]

Re: 1972 Johnson 20 shifting problem

Are you using a factory shear pin or making your own?

 

[johnson72]

Re: 1972 Johnson 20 shifting problem

factory. I bought the second one fropm the marina.

 

[johnson72]

Re: 1972 Johnson 20 shifting problem

I have two questions. Would the clutch dog slipping at plowing ( before you plane) mode break the shear pin? If the clutch dog is worn, would it slip and then work for a few days and slip again?