Merc 8.1HO's - oil change necessary after only 15 hours?

[psubill78]

We bought our 'new to us' boat at the end of June. She had the oils/filters done just before she went in the water in May. We've put under 20 hours on her this season (the only usage since the last oil change) - does it make sense to do an oil change on the engines, or can we get another season out of it? Our season will be ending in less than a month here.

I'm generally very meticulous with maintenance, and don't mind spending the $$, but it seems so wasteful to do it after such a short usage.

Thoughts/suggestions?

 

[Pseudomind]

I have heard it used as a recommendation to change at least once a year whether you have many hours used or not, moisture from condensation and other contaminants especially around salt water. I think if I were you I would wait and change it in the spring, since you put in new oil and filters in May, but I would change it before using in the spring. Due to the information provided with you user name, (location in this case) in you thread. I am guessing you do some type of winter storage or preparation. THIS IS JUST A GUESS however. Hopefully someone who is more familiar with northern climate issues will chime in.

 

[firecadet613]

I change in the fall of every year just to be safe. That way you have fresh, clean, uncontaminated oil in your engines over the winter. Now saying that, I have never heard of an oil related engine failure.

 

[Westie]

This is from the factory servive manual for a 7.4.
"Every 100 Hours Of Operation
Or Once Yearly, Whichever Occurs First"
Your 8.1 may be different but the best thing to do is check the Mercruiser Service manual.

If you are going to change it (which I would do if I were you) do it in the fall and not the spring, as it is better to have fresh oil in it durring layup.

 

[BrewCrew]

I had a similar situation. Bought the boat in the spring, changed the oil over the July 4th week and put maybe 30 hours on it over July and August. I spent the time and money last weekend and changed it again before having it pulled last week. I changed it because the oil in the motors when I bought it, was really dirty. Wanted the least amount of that residue sitting in the motors all winter so I figured a change would help a little. Probably a personal decision though, if you can live with it, the motors will probably be fine without a change.

 

[Escapade]

Your safe if you change the fluid and leave the filters at 20 hours. Personally, I change oil just prior to seasons end and run the boat 3-4 hours on the new fluid prior to haul out. That way I know the internal components are coated w/ new juice for the winter.

 

[psubill78]

Thanks guys - always good to see the other opinions out there... in the scope of things, an oil change is nothing when you are talking about the $$ we spend on these things...

 

[Henry Boyd]

The products of combustion, combined with moisture (that's also part of the engine operation) will create an acidic state in the oil. Running the engine after the oil change should be kept to the absolute minimum. Personally, I'd also change the oil filter its not a terribly huge expense and a new filter with clean oil in it seems better than an old filter with a slug of last year's oil.

Henry

 

[skolbe]

I couldn't get to our boat until almost Fourth of July. The marina was flooded - since the weekend after I dewinterized. I have 20 hours on the boat and will have probably 35 total this season. I will change the oil. The transmission fluid - I have not made up my mind yet. I change it annually and questioning this year if I should.