cracked shift boot on lower unit

[misterpancho]

I was changing the impeller on my 40 hp 2002 3 cyl mercury and I noticed some small cracks in the rubber shift boot.

Clearly it should be replaced, but I'm wondering if that is supposed to provide a water tight seal or if its more to keep crud out. In other words, if it's had holes in it and been run in the water should additional things be checked?

I haven't drained the gear oil yet but when I do I imagine I'll get a better indication of what's been able to leak through.

 

[Mercurylips]

That boot is not a watertight seal. As you say "helps keep the crud out".

 

[misterpancho]

ok thanks, one less thing to worry about!

 

[tommarvin]

I think the shift shaft boot needs to be water tight.
Be careful not to pull the shift shaft out when changing the boot/seal
You should drain the gear lube, You can do a pressure/vacuum test to see if there's a leak in the lower unit, if not , you could refill with gear lube, and get new washers/seals

 

[misterpancho]

I replaced it today. The bottom of the boot is just held on with a wire tie. I'm not very impressed with that design if it's supposed to be a water tight seal. I changed the gear oil and it was a little greenish looking. I'm not sure if that had to do with water or just the oil being really old.

 

[tommarvin]

Can you use a hose clamp in place of the wire tie?
There's no missing water in the gear lube.
Did you get a new rubber shift boot, if so I think your good to go boating.

 

[misterpancho]

Yes, I replaced the boot. Thanks for the help.