Outboard oil changes

[harvey lee]

How many here change their motor oil in the fall instead of the spring.

If I remember correctly, Mercury said I should change it in the fall before I put the boat in storage. I use to always change it in the spring.

[goose89]

Depends on how many hours I've got. I had 100 hours on my main motor oil earlier this fall. Changed it then. I've got 35ish on this oil. My Yamaha service guy told me wait til next 100. Most times 100hours or close to it coincides with putting boat away (winterizing), so it just goes hand in hand with winterizing....but, it does't have to. I don't see any benefit from waiting til spring, unless your gonna run it til it's recommended oil change time period. good luck........

[reinhard1]

i have a Merc 115 four stroke yr 2001. i change mine every spring. good luck.

[Sonicrunch]

Fresh oil would be better for the long winter. But like goose said, if the oil is relatively new, I'd leave it till spring, and change it in spring.

Think about corrosion factors. That is your main concern.

[ib_jigged]

If you are going to not use between the now and the spring oil change, I would change now and have fresh new good oil in motor all winter.

[Kyhl]

I check it in the fall. If clean, no moisture, and good viscosity then I leave it until spring.

[goose89]

I'm curious why alot of us are changing the oil according to season and how the oil looks. Unless we're talking about lower unit oil. I can see water and if it's milky, but I assumed the OP was talking engine oil (IE- 4 stroke).

I couldn't tell you if it my main engine oil has proper viscosity. And if it "looks fine" now, why wait til spring to change it, or change it in the spring at all??

Does engine oil that doesn't have alot of hours on it degrade over 3-4 months??

How many of us are paying attention to the hours they have on their oil vs. changing with their preferred "season"??

[goose89]

.. But like goose said, if the oil is relatively new, I'd leave it till spring, and change it in spring.

Think about corrosion factors. That is your main concern.

I didn't say change in spring, I change my oil based on hours of use.

What corrosion factors are we concerned about r/t if engine oil sits over winter???

[harvey lee]

I am almost positive that Merc dealer said my 4 stroke should never be stored with dirty oil as the contaminenets will be there all winter while being stored.

I have no idea if that is correct but I am going to call mercury and ask them if fall before storage is better for the motor.

My oil was changed in spring, put about 75 hours on it and changed it in mid July. I would guess I have at least another 50-75 hours on the motor since the last summer oil change.

[harvey lee]

I got my owners manual and maintenance manual out and checked this out.

Due to contaminents in the motor oil, Mercury does suggest to change your motor oil in the faLL before you put the boat in storage.

[goose89]

Interesting Harvey Lee. Looks like I"m gonna have to make a decision. I've got 40 hours on my last change. Might just have to do it before I put it away. I've got a few hours to put in it before storing, but not that many get close to 100.

Anyone care to explain / educate me about 4 stroke engine oil contaminants?? Thanks in advance.

[goose89]

After some "googling", looks like I'm in the change in fall camp, even if I'm not at recommended oil change time. I don't understand all the processes, but if the info I found is true, contamination is an issue.

Still would like some FM wisdom to back this info up. Thanks again in advance.

[kapp]

changing it out in the fall is mostly just to make sure there is no water

in oil, if there is it can freeze and harm the lower unit, so i think if you check it and looks good there is no reason to change now. mercury is

concerened about contaminents ( moisture) as well so change it to be on safe side.

[boatfixer]

You are correct as far as the lower unit goes, however the OP was referring to the engine oil and filter in a 4 stroke engine. Good point on the lower tho!

[goose89]

boatfixer, what's your experience / wisdom / opinion on this?? For example, If someone's got 40 hrs on an oil change (done in September), is it necessary to change the engine oil before putting away for winter?? How about 20 hrs?

What do you know about said contaminants?? Are they formed as the engine hours add up on the oil change? If not, then why do we store them over the winter with oil in them at all?? The contaminants issue is new to me. Thanks in advance.

(The lower unit oil fall change I understand).

[slammer]

If your using mineral based oils, they should be changed in the fall and again in the spring as waxes will form just from sitting if the temps are low. Dont know if this applies to outboard oils as some of these are probably semi or full synthetic.

[Northlander]

I change my engine oil and lower unit out in the fall and half way through some summers if I put a lot of hours on my motor. Now that I have a kicker I dont have to do it like I used to.

[marine_man]

I prefer to do it in the winter. I have to change the lower unit oil anyway, I'd just as soon put the boat away ready to go for spring then do some maintenance in the fall (when I have "time") vs the spring when I'm chomping at the bit to use it.

marine_man

[delcecchi]

If your using mineral based oils, they should be changed in the fall and again in the spring as waxes will form just from sitting if the temps are low. Dont know if this applies to outboard oils as some of these are probably semi or full synthetic.

What? Do you have any documents that would back up that somehow fresh oil goes bad just sitting in the engine? How about in the bottle?

I am skeptical.

[boatfixer]

Goose-While im no expert, I do prefer to change in the fall. I prefer it for a couple of reasons. The 1st for the fact that there are acids that are the result of the combustion process. Acids that can and will cause corrosion inside the engine. Now heres the part that I waive my status as any kind of expert. I cannot tell you at what point the acid levels reach a point at which they become corrosive. I do realize and understand that there are some variables that can affect contamination such as moisture, engine temps (higher temps may boil off acids), excessive trolling or low speed operation and also that there is no "air filter" to speak of. Although we operate marine engines in a relativly dust free enviroment, there are still some airborne contaminents that can and more than likely do, enter the intake and eventually wind up in the oil.

The 2nd reason is for convenience. Make it part of your fall routine. Put it to bed clean and its ready to go in the spring.

Would I recomend someone at 10 hrs? I dont know that I would push it real hard. 20? Well look at it this way, you didnt spend alot of money on gas so why not splurge a little and take special care of your baby! 30? ya I think its certainly NOT a waste of money. More than that and I think its money well spent.

[boatfixer]

As far as the waxing thing goes, mineral based oils do contain some waxes, however it my understanding the waxes become more viscous only because of temperatue loss and that issue goes away as temeratures increase. I would say its a non-factor

[CAMAN]

I will agree with Boatfixer and also add that contaminants in the oil leftover from the combustion process that are too small for the filter to catch will settle to the bottom over the winter and possibly "sludge" up. When sludge forms it is almost impossible to remove without tearing the entire engine apart. And sludge is kinda like cholesterol in the blood, it has a chance of pieces breaking loose and getting stuck in oil ports if the filter doesn't catch it first. If ports begin to get clogged the locations the port is feeding will get no lubrication and cause more severe problems.

And for those wondering if oils will go bad, AMSOIL recommends a shelf life of an UNOPENED bottle of all their oils stored in a cool dark place to be 5 years, and I see non-syn oils have a shelf life of around 3-5 years also. It's not the oil going bad they are worried about, it is the additives they mix with them that settle out and separate from the oil. If the bottle is clear like AMSOIL uses you can see a distinct separation line between the oil on top and additives on the bottom if the oil has gone bad.

[goose89]

boatfixer, makes perfect sense. Good advice and rationale. CAMAN, thanks for your input, too. I wasn't aware of the acids and contaminants.

[Capt. H (Ret.)]

I have an Optimax so I don't deal with the problems of when to change engine oil. I change the oil on everything I own at the end of the season so it is ready to go next season. This includes lawnmower, snowblower and pressure washer. At the price of a new outboard I don't see the minimal cost of oil in comparison to the cost of the motor as a factor. CHANGE IT!!!! and good boating next spring!!!!

Mike

[Kyhl]

Changed mine Saturday as part of winterizing. Maybe 20 hours on it and it looked dirty so why not change it.