Boat oil change?

I’m getting close to my 100hrs on my boat motor this year. I plan on changing oil this week after work one night. My question is I usually change the oil when I go to put the boat away for the winter, but I have had a good year and got a lot of fishing in this summer. Should I change it again before I park it for the winter or just wait for the next 100hrs interval? I will change the lower unit oil when I go to put it way for winter. Every oil change cost me about 55$ so I want leaning on changing it again since it is cheap maintenance and hoping to make the engine last as long as possible. It’s on a 2016 Mercury 200hp verado. Any on-site would be great.

No reason to change it again before winter. Wasteof money and resources for no gain.

And don’t believe anyone spouting bs about acid build-up in the oil, blah blah. Total myth.

Grouse

I wouldn’t change it again before winter unless you are somehow close to your next interval again.

Also, don’t fill your new oil all the way up to the top of the dipstick. Fill it up to about the middle of your hashmarks. This leaves some room if you “make oil” in the cold water coming up.

Thanks for the info. It says right in the owners manual to only fill to have of the dip stick marks. I’m still confused on how it makes oil but I know that some how they do

TheFamousGrouse wrote:

No reason to change it again before winter. Waste of money and resources for no gain.

And don’t believe anyone spouting bs about acid build-up in the oil, blah blah. Total myth.

Grouse

Can you provide a link about this myth?

All have found is that sulfur (small amounts in the oil) combined with nitrogen (from the air) oxidizes during combustion to become mildly acidic. The amount of oxidation is directly related to engine temperature. Every 18F increase in temperature doubles the rate of oxidation.

So your F’d either way. Run it for short trips where it doesn’t heat up and you build up moisture. Run long trips and you increase the amount of oxidation, increasing acidity.

Until someone can supply proof of the myth, I’d still believe in the build up of acidity in the oil and would still change it in the fall before it sits there for six months.

Kyhl wrote:

<div class=”d4p-bbt-quote-title”>TheFamousGrouse wrote:</div>
No reason to change it again before winter. Waste of money and resources for no gain.

And don’t believe anyone spouting bs about acid build-up in the oil, blah blah. Total myth.

Grouse

Can you provide a link about this myth?

All have found is that sulfur (small amounts in the oil) combined with nitrogen (from the air) oxidizes during combustion to become mildly acidic. The amount of oxidation is directly related to engine temperature. Every 18F increase in temperature doubles the rate of oxidation.

So your F’d either way. Run it for short trips where it doesn’t heat up and you build up moisture. Run long trips and you increase the amount of oxidation, increasing acidity.

Until someone can supply proof of the myth, I’d still believe in the build up of acidity in the oil and would still change it in the fall before it sits there for six months.

Is the myth is DOES or DOESN’T cause acid build up?

Google Briggs and Stratton No oil change ever lawn mowers. I’m sure you’ll be fine having it sit for 4-6 months.

Making oil is just gas in your oil, I would wait till the fall and just change it. What is another 20 hours on the oil you have in there now. Nothing is going to blow up LOL.

The myth is that somehow the tiny amount of acid generated by combustion processes will somehow eat your engine during storage and cause any number of dire problems.

What the mythmongers never address is why wouldn’t these dire problems occur during the other 9-10 months of the season? The same combustion processes are at work, doing the same things, so why does this dreadful “acid buildup” take the spring/summer/fall off and only eat an engine during the winter? If this myth were actually true, this dreaded “acid buildup” would be eating our engines 24/7/365, not just in the winter during storage.

Change oil at recommended intervals and enjoy life.

Grouse

bigcrappie wrote:

Making oil is just gas in your oil, I would wait till the fall and just change it. What is another 20 hours on the oil you have in there now. Nothing is going to blow up LOL.

This makes more sense to me, instead of a set number. As long as it still is viscous I’d wait and change it at the end of the season.
If worried, just change the filter and top it off as long as it still is viscous.

I used to change it in July and the end of the season, twice a year. On my old motor (2004) it would lose viscosity by mid-July. You could feel it in your fingers. The newer (2014) motor, seems to last all season. However it holds nearly two gallons, like 7 quarts. That might have something to do with why it holds up longer.

The lower unit? When was the last time you changed the differential fluid in your truck? I gave up on changing that. I check it each fall to make sure it is clean, no water, by giving it a few pumps of new stuff from the bottom up. As long as it’s clean, I button it up. I don’t change that every year.

ClownColor wrote:

Google Briggs and Stratton No oil change ever lawn mowers. I’m sure you’ll be fine having it sit for 4-6 months.

Thanks. I did a quick look and see they tout a couple of changes that make this possible.

A.) Lowered engine temperature. If they lower the operating temp by 36F they can quadruple the time between oil changes, aka reduce oxidation of the oil by 75% (see above).

B.) And improved air intake to better filter the incoming air.

Responses:
a.) Outboards most likely have not lowered operating temperatures. If anything, the OP’s Verado might go the opposite direction because it uses a supercharger. I haven’t looked in a few years, but I’m assuming they are still supercharged.

b.) I’ve never seen a boat motor with an air filter. My current motor (2014) does have a course wire screen over an intake horn. Flies, spiders, cotton wood seeds, maybe even a ball point pen would fit through there. None of my previous motors even had a wire screen over the intake. Just a hole leading to the cylinders.

c.) I bet a typical lawn mower could normally go four years without an oil change before this B&S motor. If they can quadruple that it would last 16 years. Like everything else, they will eventually die. 16 years without changing oil would be a good run.

It is a fallacy of transference to assume that because one motor works one way, then they all should.

For what it is worth, I’m 14 years into a mower that receives regular oil changes. It still starts on the first pull, however that means nothing compared to a boat motor.

You need to be far more concerned about oil dilution than you need to worry about wearing your oil out, or acid, or anything else.

Every four-stroke outboard is susceptible to “making oil.” (unwanted fuel in the crankcase)

If you follow your break-in recommendations and treat your fuel religiously, you’re less apt to see that problem.

The short of it……your engine adds extra fuel at lower rpm’s to keep the operating temps where they need to be. The process is amplified in colder water.

If your rings are not seated properly from break-in, or you have carbon build-up (un-treated fuel), you will likely have some excess fuel slip by your rings and be deposited into your crankcase (making oil).

It can happen with any make of four-stroke.

Follow your break-in, treat your fuel, and don’t be afraid to open it up and burn some dinosaurs to heat your oil up (which burns off fuel in your crankcase).

Kyhl wrote:

<div class=”d4p-bbt-quote-title”>bob clowncolor wrote:</div>
Google Briggs and Stratton No oil change ever lawn mowers. I’m sure you’ll be fine having it sit for 4-6 months.

Thanks. I did a quick look and see they tout a couple of changes that make this possible.

A.) Lowered engine temperature. If they lower the operating temp by 36F they can quadruple the time between oil changes, aka reduce oxidation of the oil by 75% (see above).

B.) And improved air intake to better filter the incoming air.

Responses:
a.) Outboards most likely have not lowered operating temperatures. If anything, the OP’s Verado might go the opposite direction because it uses a supercharger. I haven’t looked in a few years, but I’m assuming they are still supercharged.

b.) I’ve never seen a boat motor with an air filter. My current motor (2014) does have a course wire screen over an intake horn. Flies, spiders, cotton wood seeds, maybe even a ball point pen would fit through there. None of my previous motors even had a wire screen over the intake. Just a hole leading to the cylinders.

c.) I bet a typical lawn mower could normally go four years without an oil change before this B&S motor. If they can quadruple that it would last 16 years. Like everything else, they will eventually die. 16 years without changing oil would be a good run.

It is a fallacy of transference to assume that because one motor works one way, then they all should.

For what it is worth, I’m 14 years into a mower that receives regular oil changes. It still starts on the first pull, however that means nothing compared to a boat motor.

Good info and I’m sure you are correct…but I was only referencing to the fact that oil can sit for extended periods of time…you know, to the whole acid build up blah blah blah being discussed. But that’s crazy thinking that a boat motor and lawn mower motor are different…what’s next, a car motor differs from my ice auger? You crazy, man!

Here’s one difference: Car motors cruise in the 2000-2500 rpm range. Outboards 5500-6000 rpm. Makes me nervous enough to be pretty careful with maintenance.

While your typical car engine will be in the 1700-2200 rpm on the highway, they could probably easily handle a steady diet of 4000 rpm if need be. Towed my boat in some very hilly terrain at times, and routinely was in the 3000 rpm plus range. No problem with todays engines and oils, and that’s with an operating temperature in the 210 deg range. People forget to take in account that outboards operate in the 160-170 deg range and are much easier on oil than a car engine. It seems that the main benefit to a W rated outboard oil, is in their corrosion protection. Having had a bay boat that sat unused on a lift for 7 months of the year, over salt water, you want that corrosion protection.