Small outboard surgery

[s2sailorlis]

In my quest to squeeze the maximum value from my 1995ish Tohatsu M5B….

After seeing the prop shaft seal leaking…original plan was replacing the shaft bearing and seal. Simple, right… well first one needs to remove the shaft housing…not easy…;) was a Herculean effort removing the housing whilst leaving prop shaft unscathed… I did it but destroyed housing in process…

$75 later…new housing, but that included the shaft and seal already pressed in place! Big time saver…

The motor runs strong..not perfect but strong…expected as it’s Flintstone tech….

[bgephart]

Congratulations on your successful repair. One question - how did you know that your shaft seal was leaking? Was the gear oil milky? Or loosing gear oil? Thanks.

[sgbernd]

I read a source which stated that when old small outboards lower units start to leak, you can drain all the gear oil, pump the year box completely full of water proof grease and leave it at that. It is not ideal, but according to this mechanic, you can get several more years out of them and usually they are approaching their end of life anyway and replacing a lower seal is difficult and expensive relative to the value of an old engine. He did not advise the procedure on more powerful outboards but for the pint sized ones, there is not enough power running thru the the unit to get hot and the grease provides sufficient lubrication and repels incoming water. I have not tried it as my outboards have all failed at the upper end but it might be something to consider.

Steve

[s2sailorlis]

Sorry for delay…I didn’t see the question. Yes milky oil, and then performed a pressure/leak down test.

Congratulations on your successful repair. One question - how did you know that your shaft seal was leaking? Was the gear oil milky? Or loosing gear oil? Thanks.

[s2sailorlis]

Interesting idea..but any water in the LU will wreak havoc on the gears and all.

My perspective is $75 isn’t a fortune relative to motor value. The replacement took 10 minutes to install. It runs very well, idles fine and has strong compression. Is it Smokey and noisy? Sure, but for my use of getting in/out of marina it’s fine. it’s flint stone technology and these older 2 strokes, when cared for, can last a long time.

I could easily spend the $1.8k for a new Tohatsu SailPro, but they've been back ordered for nearly a year. I’d buy the Mercury version for $1.5K but it has a lesser warranty, no alternator, and uses a standard prop. I’ll wait for the supply chain issues to work themselves out..I can imagine they’re slipping these engines together and getting them out the door so I suspect quality will suffer… I’ll wait until 2024 when things approach near normalcy…

I read a source which stated that when old small outboards lower units start to leak, you can drain all the gear oil, pump the year box completely full of water proof grease and leave it at that. It is not ideal, but according to this mechanic, you can get several more years out of them and usually they are approaching their end of life anyway and replacing a lower seal is difficult and expensive relative to the value of an old engine. He did not advise the procedure on more powerful outboards but for the pint sized ones, there is not enough power running thru the the unit to get hot and the grease provides sufficient lubrication and repels incoming water. I have not tried it as my outboards have all failed at the upper end but it might be something to consider.

Steve