Johnson 5.5 Prop won’t fit

[JohnRude]

I’m hoping that somebody can solve a mystery. I have a 1958 Johnson 5.5 and a 1957 Johnson 7.5. The 57 came with a three blade beat up bronze prop which I removed. I took the prop off the 58 Johnson 5.5 and put it on the 7.5 to run some tests in the test tank. Some of you guys have been helping me with it in another thread. Here’s the mystery. I removed the 7.5 from the test tank, removed the prop and put it back on the 5.5. IT DOES NOT FIT.

It goes over the shaft fine but I can’t push it down far enough to to get the shear pin and cotter pin in their respective holes on the 5.5 anymore. I used this motor all last fall and only touched it to change the lower end oil. The seal is flush with the bearing housing. Could it have slipped out somehow? It doesn’t move when I push on it.

I will attach three photos. One of the prop, one of the 57 that everything fits and one of the 58 with the problem.

[Mumbles]

The seal isn’t pressed all the way in on the one motor.  That might have something to do with it.

Just a reminder but stock 5.5 and 7.5 props are of different pitch. You don’t want to switch them around as a 5.5 prop on a 7.5 will allow the motor to over rev while a 7.5 prop on a 5.5 will make the motor lug.

[crosbyman]

strange I had similar  problems refitting the prop on a recent 5.5 rebuild… same prop smae  prop shaft…go figuee..

eventually got it  back in with  grease  and  persuasion ???!!

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[frankr]

File off the burrs around the shear pin hole.

[JohnRude]

Thanks. Good to know about the pitch differences. The 7.5 came with a three blade bronze and I just used the one from the 5.5 to do the tank test. However, the 5.5 prop won’t go back on the motor. I agree that the seal isn’t far enough in but I ran the motor all last fall this way. Could the seal have moved on the shaft? It doesn’t leak oil and hasn’t allowed water in. And if somehow it moved, I should be able to push it back. Never had this happen with any motor before.

[JohnRude]

There are no burrs. The prop slides freely. It just doesn’t go on far enough because of the seal sitting flush with the housing.

[fleetwin]

Mumbles wrote:

The seal isn’t pressed all the way in on the one motor.  That might have something to do with it.

Just a reminder but stock 5.5 and 7.5 props are of different pitch. You don’t want to switch them around as a 5.5 prop on a 7.5 will allow the motor to over rev while a 7.5 prop on a 5.5 will make the motor lug.

Yes, most likely this is the issue.  I ran into a similar problem when I failed to press the seal all the way in on a 58 gearcase.  You can just use a deep socket and tap it in the rest of the way.

[JohnRude]

I believe that “tapping” the prop on may have caused the shock absorber to crack and break apart. Not sure what caused it but it was definitely in pieces when I pulled the lower unit.

[crosbyman]

I just repaired one on my 5.5 Johnson… just put back together and spot weld  at the joint  use a brass drive pin on the prop .

 

 

grind away  weld bumps    kep the shaft round so it does not rub in the GC

 

#273481Edit Reply Quote

been reading lots of old posts  on shock absorber  size…. 6″11/16  seems the magic number … mine meaures  6″ 13/16 .

while initially  working the housing  I recall it falling out  on the  ciment floor  and wonder if it got  messed up then ???   anyhow… pursuing the adventure

GC gears turn fine on their own  but driveshaft turns about 3/4 turn and binds… on its own   . I’ll reinspect the  shock absorber  and  if  6″11/16 is the magic  number I’ll have my neighbour  tack weld it  at 6″11/16.

 

 

 

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