Lower unit oil question

Hey guys,

Decided the other day to call open water quits but I found out later that we might take a weekend trip here before MEA. Anyway I put the boat away and changed the lower unit oil, it didn’t look terrible. My question is for that one trip do you think it would be alright over the winter or should I change it again? The reason I ask is finding the yammalube oils in my area this year is tough as a lot of dealers are sold out.

Thanks

If it did’nt have water in before i would’nt worry about it.I would go and have a good time.

After you use the boat, let it sit a couple days. Then remove the lower plug. If a few drips of clean oil comes out your good for the winter. It doesn’t sound like you should have any problem but if water or milky oil drips out then you have issues.

What?? It’s mid September, some of best fishing

Thanks guys I will still do some calling around this week to see if I can track a quart down to have in case I wanna change it.

Craig Sery wrote:

What?? It’s mid September, some of best fishing

I know! I love this time of year but with working full time, yard work (we have a huge yard), and Cutting and splitting wood it doesn’t leave a lot of “fun time”.

Some stop fishing in July

I think the whole thing about winterizing your boat and changing out fresh gear casing lube is overblown. Do you know how much water it would take do anything? I think it’d take darn near the entire lower unit being filled with water and a hard freeze at -10 out before it’d maybe do something.

When I was a kid we never changed the lower unit oil once on any of our motors. Never once did we need a single repair to our lower units and we beat the crap out of our motors. We fish the river a lot and are constantly hitting rocks, logs, you name it. We burned through countless props. All the motors still ran great without issue. I bought my first new motor a few years ago and read the manual and change all the oil in it at or more frequent than what’s recommended. On the new four strokes I think it’s really important to change the gear casing while breaking it in but after that I think you’d be fine going years without doing it. For one, it’s a 90 weight oil and two it’s not doing anything related to a piston firing where the heat and get scorched is going to break it down and reduce the viscosity. Every year I do mine I feel like it’s pointless. Like I’m dumping out good oil to replace with good oil.

One of these years I’m going to get an old cheap lower unit and mix oil and water 50/50 and fill it it up and then sit it outside for the duration of a MN winter just to see what happens.

Oil is getting expensive I drained both motors last year and oil looked great. Now I’ll just inspect, I just remove top screw and add oil from the bottom till it comes out the top. Good to go.

I think if your seal is bad or going bad, you would notice a small amount of water in the oil between changes. Certainly not enough to cause any damage. I’ve never seen water in the lower unit oil on any motor I’ve owned?

joneser wrote:

I think the whole thing about winterizing your boat and changing out fresh gear casing lube is overblown. Do you know how much water it would take do anything? I think it’d take darn near the entire lower unit being filled with water and a hard freeze at -10 out before it’d maybe do something.

I tend to agree. I don’t think it’s a bad idea to inspect every year (see if there is an line wrapped around the shaft) and change every few years, but it’d take a lot of water to crack anything. One trip? I wouldn’t even consider changing it again.

Plenty of people use their boats all winter and I promise we don’t change lower unit oil after each trip. Consider the fall oil change just an inspection to make sure you don’t have a bad seal. If you didn’t have water before, I wouldn’t worry…