Sportmaster oil fill level practices?

**Sleek Jr** · 01-01-2021, 02:53 PM

1. Many here say they level the lower unit, and fill from bottom just until it comes out of top vent hole. A 32 oz. bottle will NOT be enough.
a. -Some say they have done this for years with no problems
b. -Others say it "blew"out the top driveshaft or shifter seals.
c. -Yet others say that if you DON'T fill to the vent hole, the top driveshaft bearing and seals will "run dry" and not be lubricated.

2. Dealer, and some others here say measure and fill only 28 oz. It will NOT come out the top vent at 28 oz.

3. Still some others here, say their manual says to fill with 24 oz., even less than above.

Which is correct? Or does it even matter?

Mine is 2007 sporty on 300xs if that matters.

**Capt.Insane-o** · 01-01-2021, 03:37 PM

Put an expansion kit on it.

**Captin Hazlewood** · 01-01-2021, 05:20 PM

On a 3 liter sportmaster, fill from the bottom until it comes out of the top then drain off about an ounce. It will take more than a quart. Maybe 34-36 ounces. I have done it this way for years and have never pushed out a seal much less burned up any bearings.

**TraceF3** · 01-01-2021, 06:24 PM

Originally Posted by Sleek Jr

1. Many here say they level the lower unit, and fill from bottom just until it comes out of top vent hole. A 32 oz. bottle will NOT be enough.
a. -Some say they have done this for years with no problems
b. -Others say it "blew"out the top driveshaft or shifter seals.
c. -Yet others say that if you DON'T fill to the vent hole, the top driveshaft bearing and seals will "run dry" and not be lubricated.

2. Dealer, and some others here say measure and fill only 28 oz. It will NOT come out the top vent at 28 oz.

3. Still some others here, say their manual says to fill with 24 oz., even less than above.

Which is correct? Or does it even matter?

Mine is 2007 sporty on 300xs if that matters.

I had the same motor/lower. I filled it like all other lowers. Blew the top seal. Bought the expansion kit. Problem solved.

**Markus** · 01-02-2021, 03:57 AM

Originally Posted by Sleek Jr

sporty on 300xs if that matters.

matters a whole lot.

2.5 liter sportmaster does not have the problems of the 3 liter

**Captin Hazlewood** · 01-03-2021, 10:59 AM

When you follow the proper fill procedure it’s not a problem. That’s why you drain about an ounce of oil off after filling. It provides the space needed for the thermal expansion. And it cost you nothing, no need to purchase an expansion kit.

**TraceF3** · 01-03-2021, 11:07 AM

Originally Posted by Captin Hazlewood

When you follow the proper fill procedure it’s not a problem. That’s why you drain about an ounce of oil off after filling. It provides the space needed for the thermal expansion. And it cost you nothing, no need to purchase an expansion kit.

I did try this. I had 3 trips in 7 hours to the l/u guy. Kept saying it was holding pressure. Kept changing the lube and getting more water.

I think when you are running the sporty at full surface for long periods of time it gets hotter than we realize. The kit stopped my problem. So it worked for my situation.

**big tom** · 01-03-2021, 02:01 PM

When you guys are talking about a expansion kit are you talking like the ones found on Bravo I/O's ?. If so is it mounted also mounted on the transom?.. Stupid question of the day..

**TraceF3** · 01-03-2021, 05:38 PM

It's not a bad question. I'd never heard of it either.

Shop | MadEFI.com

First item on the GEARCASE tab

**kellytheaker** · 01-03-2021, 06:03 PM

So I have followed the thread - am I to understand that the 2.5 Sportmaster does not take the same fluid capacity ? .
Manual states - capacity at 22.5 fl. oz. And to fill to vent and not to lose more than 33 CC. Please correct if differant . Thanks

**Captin Hazlewood** · 01-03-2021, 07:29 PM

On a 2.5 you can fill it until it just starts to come out of the vent.
Lakeland Marine makes a vent kit for the 3 liter cases for the folks who like to overfill them.

http://www.optimaxfuelrailrepair.com/services.html

**dgscroggs** · 01-03-2021, 08:53 PM

28oz for the 3L sporty , I’ve never had a problem

**powerabout** · 01-04-2021, 05:42 AM

what happens all depends on the conditions under which the box operates.
very high and hot water or very little coming down its going to get very hot blow the oil out then pull the water in when it cools

**Captin Hazlewood** · 01-04-2021, 09:41 AM

Doesn't everyone run their Sportmaster "very high"? Otherwise whats the point of having a Sportmaster? I run mine where the pointed leading edge is above just above the waterline, if I ran it any higher there would be no water pressure. It's about 1 3/8" to 1 1/2" above the bottom of the hull. For over 10 years now I have filled from the bottom to the vent hole, then lazily put the plug in allowing about an ounce to an ounce and a half of oil to drain off. Maybe I'm lucky but I have never had a problem with this case pushing out seals or ingesting water. I change my gearcase oil about monthly during the season and this boat gets alot of use. To each his own...

**4Speed** · 01-04-2021, 11:13 AM

Any photos of the Lakeland Marine system installed other than what's on their web site? It would be nice to see how the vent hose is routed and the placement of the expansion chamber under the cowl?