That Doggone Shock Absorber

[drifter]

Just finished a rebuild on a new (to me) 54 Johnson 5.5hp. Did all the usual refresh stuff – mag, carb, l/u seals, impeller, starter, etc.
I always measure the shock to 23/32″ to make sure it has not expanded.
First start up today. Started right up and came nicely into tune.
Shifted into forward and heard a “click” and motor abruptly stopped. You know right away what has happened.
So 30 minutes later I’m holding the two pieces of the shock. A clean spring break.
Now I’ve welded my share of shocks, when discovering a broken shock on a motor new to me. But, this is the first time I’ve had one break on a motor after I’ve assembled it.
So, to my question. what are your thoughts on 4 tack welds on a “good” shock before assembly?
I always use a brass prop drive pin on my motors.
Drifter

[labrador-guy]

Four tacks sounds good to me!   I too learned the hard way.   Took a motor apart three times before I found that broken shock.  You need to check the pump housing for a crack.  When that stupid shock breaks it gets longer quick and sometimes it breaks the lower part of the impeller housing.  Gear housing won’t seal for love or money!  They are getting hard to find!

dale

[reivertom]

I’ve never had a problem with one. How often does it happen?

[richardg]

Frequent if shifted at high RPMs

[Steve A W]

The oily gas is “Good to the last drop”

Member of the MOB chapter.
I live in Northwest Indiana

[Mumbles]

reivertom wrote:

I’ve never had a problem with one. How often does it happen?

Usually happens when hitting a log or digging for clams with the prop.  The spring in the  clutch slips and expands on impact, just like it’s supposed to do, then it needs to be removed and compressed back to length. The spring itself seldom breaks but I guess it does happen.

Just a heads up but if you are going to weld or braze it together and don’t have a lathe to help keep the pieces aligned properly, try doing it with the drive shaft installed all the way.  There is a small pocket inside which the drive shaft fits in and if the two pieces aren’t aligned properly, there may be a problem getting the drive shaft bottomed all the way.

• This reply was modified 1 year, 11 months ago by Mumbles.

[retiredoz]

I’ve got a couple I can get along without.

 

[reivertom]

Thanks, I guess I’m lucky. I have extra parts motors just in case, so that’s one part I’ll keep for sure.

[labrador-guy]

Mumbles wrote:

reivertom wrote:

I’ve never had a problem with one. How often does it happen?

Usually happens when hitting a log or digging for clams with the prop.  The spring in the  clutch slips and expands on impact, just like it’s supposed to do, then it needs to be removed and compressed back to length. The spring itself seldom breaks but I guess it does happen.

Just a heads up but if you are going to weld or braze it together and don’t have a lathe to help keep the pieces aligned properly, try doing it with the drive shaft installed all the way.  There is a small pocket inside which the drive shaft fits in and if the two pieces aren’t aligned properly, there may be a problem getting the drive shaft bottomed all the way.

• This reply was modified 1 year, 11 months ago by Mumbles.

I feel like I am disagreeing with the Pope here.  Mumbles is first and foremost when it comes to OMC.   Consider this, the coil spring is pressed into the shock absorber on both ends.  If it slips the shock should not change it’s length.   If the spring is broken and one end or the other slips the coils will climb up on themselves and the whole thing will get longer.  I have only had a few of these motors.  Maybe five and three have had broken shock absorbers.  One had a broken pump housing.  They are not my favorite outboard but they do run sweet when you get them right.  I will weld everyone I take apart from now on!

dale

get’em wet…don’t let’em set!!

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[Mumbles]

Yeah, but when they slip they can wind up to. Maybe the spring acts like a big screw thread. I guess I’ve been lucky as I’ve had to coax lots of these shocks back to length but have never had one where the spring was broken. Knock on wood!

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