71 Johnson 50 50ESL71S clicking when going into reverse

[dh419]

I have a 71 Johnson 50 hp model 50ESL71S that goes into forward just fine, but when I go into reverse I get a clicking sound before it goes into reverse, clicking is not a good description, but I don't know of a better way to describe it, after the sound, it will back up as normal. I had changed the oil in the lower unit, and used the wrong type, when it started clicking, I did some checking and changed the oil to the type C, so it has the correct oil in it now and has had for a long time, but still clicks when putting in reverse. I may have damaged something with the wrong oil. What do I need to check to figure out what I need to replace?

 

[racerone]

No damage done with the wrong oil.-----The oil pressure does the shifting.----Reverse requires the highest oil pressure to compress the spring on the clutch dog.-----So this machine has a strainer screen in front of the oil pump.----This screen has been known to disintegrate.---Possible damage to the oil pump rotor / parts.------Pieces go through the oil pump and end up in the shift piston bore.-----The shift piston then becomes sticky.----Hence it is not going into reverse in an instant as designed.------So I would do a complete teardown / inspection of this lower unit.----Easy for me , no manual needed.

 

[dh419]

Thanks for your reply, I have a service manual, and will have to open it up and see what is going on. I have been reading a lot about it, doesn't sound very difficult to me. Might wait a little later, get thru this season, then tear it down. Nice to know that I might not have caused the issue, I was afraid I had. I have been avoiding hitting reverse as much as I can, but sometimes I have to.