1971 Johnson 4hp shaft question

[rcspencer1]

I replaced the water pump with no problems, but when I try to put the shaft back in to the head, it engages but as I get to the very end it seems to disengage, so not sure why. I seem to be missing the o-ring (# 32 in the attached diagram), so going to try that. I don't understand why an o-ring would cause it to disengage and the gears seem to be slightly worn but not to the point where I would have to replace it, but just curious if anyone has run into this same problem? A new shaft is about $45 on ebay, so not the end of the world, but we'll see.

Thanks in advance for any advice/counsel you can provide.

Bob S

 

[racerone]

The O-ring is there to prevent water from getting into the splines.---It should not cause anything to disengage.------What did the splines look like on the shaft ( picture ) needed.------Remember that splines in the crankshaft are carbon steel and might show more damage.-----Note ----This spline damage is very common.----Seen it many times.

 

[F_R]

Agreeing with racerone. The o-ring is often ignored and left out, then water gets into the splines. The drive shaft is stainless steel so water doesn't rust it, but the crankshaft is steel and does rust. So much so that the female splines totally rust away leaving a more or less round hole. Yep, for lack of a ten cent o-ring, the motor is lost. I too have seen it way too many times.

 

[rcspencer1]

Thanks for the feedback, guys - much appreciated. On a closer look, the splines are in pretty rough shape (see attached pic), so I hate having to toss an oldie and will try getting a new shaft and o-ring and keep my fingers crossed.

Thanks again.

 

[F_R]

Yep, that shaft is toast, but not the whole problem. The crankshaft is destroyed by rust as previously mentioned. The rusted-away splines in the crank are what damaged the drive shaft. You are wasting your time and money by replacing only the drive shaft.

 

[rcspencer1]

I hear you, and appreciate the honest opinion. On to another engine...