1955 Johnson RD-17

[luckys pinstriping]

Good morning, I just purchased a 1955 Johnson RD-17 and have a couple questions.
It is a Rd-17 no letters after the 17.
Motor starts and runs but I still replaced the coils and wires to be safe. I did notice some free play in the crank up and down. IS this normal or something I should be worried about? Not sure if this could be a worn bearing or seal. I also hear a slight click when I rotate the crank clockwise with out the plugs installed. When I adjusted the point gap I noticed the sound. Seems to be 180 degrees apart when i hear it. Any ideas?
Thank you

 

[F_R]

Up and down play is normal within limits. It's called "end play". Slight click while rotating is also normal, depending on your definition of "click". If it is excessive, it likely is worn wrist pin bushings, a known problem with those engines. Again, depends on amount of wear. They can get pretty darn sloppy before causing problems.

 

[luckys pinstriping]

Up and down play is normal within limits. It's called "end play". Slight click while rotating is also normal, depending on your definition of "click". If it is excessive, it likely is worn wrist pin bushings, a known problem with those engines. Again, depends on amount of wear. They can get pretty darn sloppy before causing problems.

F_R: thank you for the response. Is there a tolerance for end play on the crank?

 

[racerone]

A 1955 model 25 HP is / was a well built motor.-----It is 65 years old.-----I would not leave the dock without a complete tear down and inspection !

 

[F_R]

I can't find a tolerance for the end play. However, the wrist pin to bushing clearance is 0.0007 min to 0.0014 max. That is for new parts. Safe to say all those used ones out there are way, way over "max".

 

[oldboat1]

If the up and down play is a wobble, the retaining ring under the armature plate support might be installed upside down -- flat surface should go up.

 

[cc67]

I redid an RD-17E a few years back. Good running motor, but heavy. Would make my 14' Richline scoot right along!

 

[racerone]

Armature / magneto plate has nothing to do with crankshaft endplay !!-----This motor is heavy compared to what ?----Likely lighter than many newer motors !!

 

[luckys pinstriping]

Thank you the info will be digging into this one deeper. when i open up the case halves anything i should pay particular attention. Clearly looking for excessive wear and bad seals but is there anything else i should look into?

 

[racerone]

If water got INSIDE the engine then bearings may be pitted from corrosion.

 

[F_R]

If water got INSIDE the engine then bearings may be pitted from corrosion.

Yes, another common problem, but I didn't want to scare you.

 

[luckys pinstriping]

Thank you guys for all the help. Motor seems clean and from the piston inspection port all looks good. Going to keep working on it as I'm sure I will have many more questions. I am looking for the front lower cowling for this motor also where would I find something like that?

 

[F_R]

antique outboard motor club. aomci.org
Post an ad there on the classified ads page. The ad is free

 

[racerone]

Any pictures with cowling off ?

 

[cc67]

Any pictures with cowling off ?

Looks like the head might have been replaced?