Change oil or not?

Discussion in 'Boats, Motors, Trailers and Towing Rigs Forum' started by DollarBoat, Oct 8, 2019.

  1. DollarBoat

    DollarBoat Member

    i am about to winterized my inboard motor and wanted an opinion on whether or not to change the engine and leg oil this year. Normally I always change the oil when winterizing but this year I only used the boat for about 20 hours and wondered if I don’t need to change the oil.

  2. scott craven

    scott craven Well-Known Member

    I would wait until spring, that oil is barely used.
  3. ab1752

    ab1752 Well-Known Member

    I always do both at lay up, particularly with the leg, so if I see something which needs attention I can get after it when the boat isn't in use. This means less downtime during spring and summer. Plus I like having clean fluids when the boat is stored.
    Robert Snyder, BCRingo and Derby like this.
  4. casper5280

    casper5280 Well-Known Member

    Always did mine just before putting the boat away for the winter, just in case there was any water in the oil there would be no chance of it freezing and breaking anything.
  5. Reel Time

    Reel Time Active Member

    Why winterize if you can run the boat once a month for a good hour. Keep the oil for next season - start the boat and go winter fishing a few times during winter.
  6. gungadin

    gungadin Well-Known Member

    Without running it and after it sat for a few days, I would remove the lower leg bottom plug. If water comes out, get the cause repaired over winter, if the oil is not contaminated install a pump, remove the upper plug, top up the leg oil, put the upper plug back in , remove the pump and replace the lower plug and you are good to go. I would change the oil after running the engine (be sure to have coolant circulating for the exhaust etc.) but not the filter. This will leave fresh clean oil with very little chance of moisture etc. left behind. Come the Spring replace both oil and filter. Of course don't forget to remove any raw water from your engine internals etc.
  7. Goathorns

    Goathorns Active Member

    the manuals have always indicated 100 hours for the 80W90 gear oils.
    I used to change engine oil twice a year, fall and spring. 100 hours per year on the main.
    So would get less hours on the 10w30 in winter than the summer 20w50. old inline 6.
  8. Wild Bill

    Wild Bill Active Member

    I always thought changing gearcase oil annually was overkill but price of oil compared to new lower I guess it's cheap insurance. My 454 big block Chevy doesn't get used as much anymore. I have about 7 hours on my ski boat in the last 3 years and that's how long the oil has been in there. Still as clean as the day I poured it in.
  9. Rockfish

    Rockfish Well-Known Member

    I change the leg oil every year on both motors and the motor oil on the Yami kicker even though we don't put many hours on it . The main is a two stroke. I also buy the overpriced high end Opti DFI two stroke oil. As you say, it is about as cheap insurance as one can get.
  10. ryanb

    ryanb Well-Known Member

    Wasting money on unnecessary maintenance is wasting money no matter how you cut it. We all waste money on unnecessary things, from whiskey to boats...change it if you like, but there is no need after 20 hours unless there is a problem like moisture in the oil which you can check without changing.
    disco likes this.
  11. zurk

    zurk Active Member

    i change it end of season to avoid old oil sitting in the motor.
  12. gungadin

    gungadin Well-Known Member

    When it comes to moisture in the leg oil I agree, it is easy to check. Even with the new oils the water will separate after a few days. However engine oil is not as easy to determine if water contamination is present. Yes, 20 hours is not much, however if your using it for trolling with fairly short trips at cruising speed then the engine may never get warm enough to "boil" off any water that has condensed within the block. There is also the chance of acids forming in the process of combustion (oxidation) which are detrimental to the engine internals. Modern oils have anti-oxidants in their formulation to help prevent this however by using an on sale motor oil from Cdn Tyre or Walmart you could forestall this process even more.
  13. BCI

    BCI Crew Member

    Oil accumulates combustion acids when the engine runs. If you're going to change it, change it before you put it away for the season. Fresh oil sitting in the engine is better than acidic oil.

    PASTE; The reason that changing before storage is a good idea is because the combustion process always has a certain amount of blowby (this is why oil gets black) this blowby causes a chemical reaction in the oil causing it to become acidic. Leaving oil in a cranckcase for months allows the acidic oil to attack seals,gaskets, etc.
    NDT likes this.
  14. wolf

    wolf Well-Known Member

    I change every 100 hours on main kicker more often and always at end of season both get done no matter how many hours as then I know starting out its all fresh and done motors are fricken expensive look after it and it looks after you, leg oils my main in summer doesnt get a ton of hours but its always checked any water it gets serviced BEFORE new season ....ever try and get service done in the spring??? sometimes its 2 to 4 weeks do it during winter when shop has lots of time and not doing a rush job....
    Derby likes this.
  15. searun

    searun Well-Known Member

    I do all my own servicing for things like oil changes, gear oil, spark plugs and every year my internal zincs. Internal zincs is the most often missed critical maintenance step. Cheap insurance over internal corrosion. Very simple process to change them out. I wouldn't be overly fussed over changing the engine oil with low hours, I'm running semi synthetic oils tho.
  16. Rockfish

    Rockfish Well-Known Member

    That is a very good point. I assume the later model Yami 9.9 HT kicker motors have an internal zinc or two. Can anyone confirm that and if so how difficult is it to replace it/them and how is it done. I do know that the later model Yami 9.9 HT that comes with the charging system and power tilt has a small extra external zinc up high that other models of the 9.9 do not have and you need to know about it and swap it out as needed, as it is easy to miss.

    How about the older model large Merc Opti's (the 200, 225 and 250 hp ones) - mine is the 225. Do they have any internal zincs I should be thinking about replacing. My Opti is a 'Salt Water Series' motor and I understand has lots of corrosion resistant parts in it. Seems to be more corrosion resistant overall than the big Yami's, - at least the earlier model Yami's.

    I did watch a guy swap out some internal zincs on a big Johnson and they (at least the ones he was changing) were nothing more than a screw head with some zinc attached on the end that you screwed in to the internal water passages. Looked very easy to replace.

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