25hp '72 Johnson gear issues

[Huron Angler]

This motor has been running great for the last few weeks after having the carb cleaned... until last night when the motor started failing to engage into gear.

She revs up and sounds strong but when forward or reverse is engaged it will no longer "catch". It basically seems like it will need a new part in order to get it fixed, just wanted to see if anyone can confirm or deny this?

Maybe buying a non-running motor to part out for it or try to see if news gears are available somewhere for older Johnsons?

Any and all suggestions are welcome, thanks

 

[lindy46]

Re: 25hp '72 Johnson gear issues

Did you check the shift rod coupler, beneath the small metal plate on the leg of the motor? Make sure both the upper and lower shift rods are secure in the coupler and the bolts are in place. You didn't remove the Phillips head screw at the bottom of the lower unit for any reason? That screw holds the shift yoke in place.

 

[Huron Angler]

Re: 25hp '72 Johnson gear issues

Did you check the shift rod coupler, beneath the small metal plate on the leg of the motor? Make sure both the upper and lower shift rods are secure in the coupler and the bolts are in place. You didn't remove the Phillips head screw at the bottom of the lower unit for any reason? That screw holds the shift yoke in place.

Have not checked the shift rod coupler.

The screw on the lower unit should be in place but that will be checked as well. Would hitting a submerged log with some force possibly have caused the coupler or yoke to have become loosened?

The motor has been used on a river and has made contact with some logs a few times.

Thanks for the suggestions lindy

 

[R.Johnson]

Re: 25hp '72 Johnson gear issues

Let's take a look at the shear pin first.

 

[Huron Angler]

Re: 25hp '72 Johnson gear issues

Let's take a look at the shear pin first.

Well we took a look at the lower unit plate and removed to find that the coupler is in place and both screws are fine.

Then we took off the prop and looked at the three broken pieces of sheer pin when they fell out.

Now we know the motor can be fixed for $3

Thanks for the help and she should be running just fine in the morning.

 

[Huron Angler]

Re: 25hp '72 Johnson gear issues

Well the shear pin was replaced with one that had a brass type color and she broke after two runs across the lake. The motor ran fine and everything for around 20 minutes.

Is the shear pin broken from throwing her into gear at a high idle?

The motor doesn't like to run unless she is thrown in rather abruptly.

At $3/2 shear pins the biggest hassle is switching them out rather than the cost so it'd be nice to get one to last a little longer.

Are shear pins made from cheaper metals sometimes? The brass colored one was purchased at West Marine.

Thanks for helping out.

 

[jbjennings]

Re: 25hp '72 Johnson gear issues

I doubt the pin would break from putting it in gear at high idle, but it will probably start to bend it and such and over time might eventually break it. However, putting it in gear at high idle is terrible for the clutch dogs. You SHOULD snap the shifter in gear quickly, but do it on low idle. You need to address that problem of the motor having to be idled up to shift without dying. It could be a dirty or midadjusted carb, dirty points, etc. I would think any of the pins that are real drive pins should be fine. You should check your propshaft and see if the drive pin hole is wallowed out from someone using something other than a real drive pin, like a nail or something. I believe a pin that's not in a nice tight propshaft hole will do what you describe.
JMO,
JBJ

 

[R.Johnson]

Re: 25hp '72 Johnson gear issues

Those brass pin's are'nt vey touch. I cut them out off unhardened drill rod, this comes in 3 ft. length's, and will make alot of pin's. Check with welding shop's,or machine supply house's.