How hard is it to change the prop shaft seal?
Other than fishing line, what could keep causing this?
How hard is it to change the prop shaft seal?
Other than fishing line, what could keep causing this?
You will need some special tools to properly change the seals. I don't recommend that the average "user" attempt gearcase repairs. There are more special tools required to repair your gearcase, than for any other part of your engine.
Another common cause of seal failures is "over filling the gearcase" and then operating at high-mounting heights.
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 48 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
Thanks for the advice.
I am concerned about this seal being torn, this is the second time in two years. The first time I chalked it up to fishing line even though I did not find any wrapped around the prop shaft. This time it is torn almost the same way it was last time.
What do you mean when you say "high mounted" could cause this?
Higher engine mounting heights (surface running) results in higher gearcase temperatures (and higher internal pressures).
Inner propshaft seal is most likely "culprit". It is "easily torn" during assembly... and will result in "exactly your complaint".
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 48 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
Ed, generally only those crazy speed freaks with the Bullets, Strokers, and oh yeah...Allisons, run their motors jacked up as high as possible. Thats why we also crack our propeller blades more often too...
Don, thanks for the info. Gonna take it to the shop this week and have a new seal installed.
OR.....boats that run excessive {max} trim angles. Anytime the prop is run other than parallel to the water surface, puts tremendous strain on the prop, shaft, and carrier bearing...at the very least. Obviously, the more you surface the case, the more the prop acts as a paddle wheel, pulling the case towards the direction of rotation. It's ONE of the reasons for a sharp and true skeg. You want to keep the g'case crab at a minimum. Sorry for the ramble, but we see a lot of water intrusion and ruined seals that have a lot to do with driver habits {due to boat set-up} that may be otherwise self-correcting.
Okay just heard from the shop, they said it looks as if the carrier is worn or wallered a bit and replacing the seals would probably be a temporary fix. He said I need to replace the carrier as well, does this sound right?
Yes. It is not uncommon for the carrier to develop an "out-of-round" seal surface area. As previous posts have stated the side forces are huge, accelerating wear. Make sure the new seals are installed with locktite and any burrs on the prop shaft removed to avoid seal tear. :)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by redline »</TD></TR><TR><TD CLASS="quote">Yes. It is not uncommon for the carrier to develop an "out-of-round" seal surface area. As previous posts have stated the side forces are huge, accelerating wear. Make sure the new seals are installed with locktite and any burrs on the prop shaft removed to avoid seal tear. :)</TD></TR></TABLE>
+1
Additionally, a "single round" of 3" wide masking tape (over the propshaft splines), then some 2-4-C on the tape greatly eases installation (and greatly decreases the probability of seal damage).
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 48 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
Got my boat out of the shop all fixed up, after replacing the prop shaft seals and doing a pressure test he found that I had a vacuum leak that he thought might be causing water to be pushed into the lower unit. Changed water pump and rear mount seal carrier Hope that was the issue causing these seals to go out prematurely. Thanks for all the advice on this lower unit issue.
BTW... we don't "vaccum test" Mercury gearcases- the shift shaft seal will leak on a vaccum test- even if it's brand new!
Dual Mercury Master Technician- for Mercury Outboards, Mercruiser and Mercury Racing at European Marine in Greenville, SC.
Still consider myself a "Marine Apprentice" after 48 years (learn something new every day).
Mercury Parts, Mercury Outboards, Smartcraft & Accessories, Injector Service, TDR Reeds- BBC Sponsor
Reply With Quote