sportmaster lower unit

**fordboys4x4** · 09-02-2025, 12:20 PM

Anyone out there that can help would be appreciated!! We just had a sportmaster lower unit gone over on a mercury 2.5 and looking for a way to protect the driveshaft as it is not stainless and is being used in salt water? Any coating to protect or paint to keep this in top condition? Other than flushing or grease. Grease will not hold up!

**pkstv** · 09-02-2025, 05:41 PM

Buy a stainless drive shaft for a regular lower unit . They made the titanium shafts for sportmasters so when they came off a big wave they would not break on re entry . Stainless steel shafts are fine if you’re not offshore racing . And won’t rust at the oil seal . Leak.

**fordboys4x4** · 09-03-2025, 10:05 AM

Stainless is not available for this. The only way we found was to re-work a 3.0 litre shaft to fit from what we here.
Thanks for getting back to us.Do you know of anyone that would have a stainless shaft for a 2.5 20 inch Sport Master??
We were lead to believe that there is no such animal out there,

**billybob** · 09-03-2025, 10:50 AM

Really you need to worry more, about the Driveshaft, where it meets the water pump base. Salt water will attack it more than you can imagine. You can pull prop. & clean propshaft, but no one hardly ever checks driveshaft at W/pump base. Every time you pull L/U off, pull W/pump base & check. Always fill space between seals, with a good water repellent grease.

**pkstv** · 09-03-2025, 04:26 PM

Buy a 3ltr 25” stainless drive shaft and take it to a machine shop to have it cut down and splined like what you have . It’s still not too bad of cost IMO . Good luck

**pkstv** · 09-12-2025, 04:12 PM

Or buy this one

**25two.stroke** · 09-12-2025, 05:41 PM

Still won't fix his corrosion problem. They aren't made for extended saltwater use. Hes better off having a stainless one made. The propshaft hes still stuck with...change em out when they rot. Unless someone can make an aftermarket one; but I don't know that I would trust stainless in a surfacing application. And I can't image how much a custom propshaft would be.