Boat oil change at layup or recommission?

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I like to have new oil in for winterization to get the acids and contaminants out of the crankcase for storage. New oil should protect for corrosion during layup. This means that oil that is used for one startup sits in the crankcase and deteriorates for 5 months.

Which is most important getting the oil out after the season, or having fresh oil for the start of the season?

I currently do oil change at layup, but would like to have fresh oil in the spring.
 
I would continue doing what you are doing. After the winter the oil should still be in great condition.
 
Change it before layup, you don't want used oil sitting in the sump, settling out making a film on the bottom, acids eating into delicate bearing metals, etc. The new oil shouldn't really deteriorate during storage much, if at all during storage. Best to make that last run before storage a long one and get up to full operating temp to drive away volatiles like fuel and water dilution.
 
I have always been told to do it before you store it. I add stabil or whatever you are going to use to the fuel. Almost more important these days is the fuel. The ethanol they have added to fuel has caused a lot of problems for boaters. I fill my take with gas, add marine stabil and run it till it gets hot. Change the oil. Then I run my with antifreeze flowing until it is almost done, fog it and kill it. Then I pull my engine drains. I also change my drive fluid at the end of the season.
 
I always change right before layup. New oil & filter and fuel water seperators. Stabil in the gas too. Starbrite also makes an oil stabilizer additive that I sometimes add to my oil which neutralizes acids. All are available at West Marine.
 
Two things on that, one being how many hours on the oil and the other, where is it going to be stored? If your engine isn't close to 75-100 hours, I think your just wasting money by changing out the oil. Marine engine oils are pretty robust, about the same as a HDEO. I just don't buy the acid theory if the oil is still good. This would especially apply if your parking your boat inside a closed storage area whereas condensation isn't going to be a problem. I mean, you think everyone does this as religiously as us BITOG brethren? Probablyt not. There is another thread on this subject that a marine mechanic for X number of years has never seen an engine die out because of wear issues, it's always some sort of mechanical issue. I know, 4 to 5 quarts of fresh engine oil isn't going to kill anybodies budget, but if the oil is still good, I just can't see getting rid of it. I feel the same on the outdrive fluids. Now, I'll loosen up the drain screw on my Alpha to see if I got water intrusions, but if not, and I don't have more than 75 hours on that drive, I'll let stay in. Drop the outdrive when you store it and finished.
 
Originally Posted By: Schmoe
If your engine isn't close to 75-100 hours, I think your just wasting money by changing out the oil.


I just posted a similar question in another thread.

Now, what would be the max time you would allow on one oil change?

I'm averaging 10 hrs a year and changing annually so far (clearly an overkill).
 
Originally Posted By: Schmoe
If your engine isn't close to 75-100 hours, I think your just wasting money by changing out the oil.


The factory OCI on the majority of my Merc engines has been 50 hours. My Horizons I have now are 100. I change at 50 hours or 1 year. An oil change costs me $100 for 2 engines if I include the fuel water seperators. Not worth the chance of developing an issue based on oil.
 
Change at max 50hrs. Maybe if you run it for like just a few hours, it's ok to skip the oci in the fall, but it may also be worse to skip it then due to moisture.
And ALWAYS change on layup! Then the new oil will protect during winter without contamination that may be corrosive.
 
Please explain how having fresh engine oil will protect your engine from moisture when it's laid up for the winter? The oil will completely drain to the oil pan. That's why it's important to fog your engine when winterizing, to get a good coat of oil over the cylinders, walls, valves, and piston rings. As I mentioned in my earlier post, it really depends on where and how you store your boat during the winter. I may have been a little high on the hours, but I meant 50 hours. I'd also do the oil napkin test to see how it travels just for some relief. I know color is no indication of oil condition, but I checked my oil in my 3.0 this weekend and it looked dang near brand new, clear and light tan. Now, this was after sitting for three weeks. Usually the top of the dipstick will be clearer due to gravity, and the bottom of the dipstick will be dirtier, but this wasn't the case with this engine. This will freak you, that oil, Pennz. LL 15W-40 with AC/Delco filter, was changed in 2006. It was laid up from 09/2006 until May of this year. I knew it would be laid up that long, so I put fresh oil in it and anyway, it was due also. Boat is stored inside and enclosed, with a cover. The engine may have 20 hours on it, if that, by the end of this year. I'm planning on fogging it, check the outdrive fluid, stabilizing it by running it close to empty and good to go. I'll do the rest of the stuff, hit the grease zerks, bearings, remove battery, etc. etc.
 
There are more expertise than myself here but this is how I reason:
Fresh oil during storage:
- Very little fuel residue, corrosives and water in the oil.
- If a marine type it may also have some conserving properties when new, like your fogging oil.
- The manual states that the oci is something like X hrs OR yearly. Maybe just for fun, but I don't think so.
- If you follow that hint, you are going to change the oil anyway yearly, so why not in the fall?

Old oil:
- Fuel and water residue and some contaminants that are known to be corrosive.
- No saving unless you are going to run it on the same oil again. I don't think it is wise to ignore the yearly oci instruction unless you have really low hours and I mean single digits.

On the other hand, your eninge may be raw water cooled in salt water. Then the exact oci and such will not be a differentiator in life expectancy.
 
OK, I see where your coming from now. Mine is raw water cooled in fresh water. Also, as with car engines, you got to run them for a while, and not just for a few minutes. This will effectively "burn" out the moisture and fuel dilution probable situation that you describe. And yes, you are correct on that, but I'm just in the school that if the oil is still good, why waste the money. But, it is to each his own. In your environment and conditions, I would probably be thinking along the same lines as you would my friend.
 
I have read that 4 stroke outboard engines frequently have fuel dilution issues, particularly if they are used for trolling. As a result, I change my oil every other fall, regardless of appearance. I do it every other year as the engine gets less than 15 hours a year.
 
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