annual oil change - how important?

[sam31]

Hello,

I'm new to the forum and looking to buy my first boat. Dealer is selling a 2012 with Mercruiser 350 Mag MPI 300HP engine with 200hours. The boat had all typical maintenance done EXCEPT annual oil changes. Oil was changed once after first season and again at the end of last season. Both times with 15-40W marine oil.

I would like to hold onto the boat for several years, but worried I'm taking a risk with an engine that had same oil in it for 4 years. Boat is in great shape and dealer offered engine warranty through next season.

I welcome any thoughts and opinions. Thanks!

 

[Scott Danforth]

boat maintenance is a calendar event, never a number of running hours.

oil should be changed annually as combustion processes start to develop acids in them which eat the bearings. that is why the maintenance schedule is X number of hours or every year, which ever occurs first

 

[muskyfins]

It's always a crap shoot on a used boat. If you buy a 10 year old boat from the second owner and he changed the oil annually for the last 5 years, you still don't really know what happened the first 5 years.:noidea:

The fact that the dealer is giving a warranty until presumably October or December of 2018 is a benefit. Especially if anything not related to missed oil changes happens.

Personally, i also see it as a good sign if you can prove all other maintenance was done.

If this boat is somehow superior to others you are considering, and you have appropriate oil pressure at idle, it might be worth the risk. As I said, if the dealer didn't tell you (or even if he lied), you'd be none the wiser.

 

[redneck joe]

^^what he said, especially on the warranty. Just make sure you use the crap out of it during the warranty period. Run hard and often.

 

[Leardriver]

I wouldn't be afraid of that motor if your other requirements are met.

 

[Scott06]

A good friend of mine never changes his oil in his 5.0 in his 1999 bayliner, been four to five years. He winterizes, drains the gear lube, checks for water in the lube and pumps the same lube back in. No joke, has to be more work to put the old lube back in. I shake my head at him but never seen him have an issue, so if you buy it and change the oil you'll be fine.

 

[khe]

A good friend of mine never changes his oil in his 5.0 in his 1999 bayliner, been four to five years. He winterizes, drains the gear lube, checks for water in the lube and pumps the same lube back in. No joke, has to be more work to put the old lube back in. I shake my head at him but never seen him have an issue, so if you buy it and change the oil you'll be fine.

Never changes the engine oil and re-uses gear oil??? That's beyond cheap, it's asinine... The anti-wear additives in engine oil get depleted over time with use - especially with an engine that has a distributor. I wouldn't want to buy a boat from him...

 

[fhhuber]

Dealer records may not show oil changes done by the owner at his house. Its not hard to change the oil and you can save time of the boat being in the shop (and not available to be on the lake) by doing it yourself.

 

[QBhoy]

Very important.
I'd say it's not as simple as a calander event. I've already changed my oil twice this year, because I've logged over 100 hours.
Every 100 hours or annually, which ever comes first is a good general guide, but also take into consideration the way it's used or the way the oil feels and smells when checking the dip stick.
Some folk I know run their engine at tick over on the mooring or at anchor for long periods of time to charge the batteries. This usually means that you will fill the sump full of petrol over the course of the season...especially with a carb engine. The engine doesn't get up to running temp and unburnt fuel gets by the rings and into the sump. I'd bet that a huge number of boats engines oil will stink of petrol towards the end of the year...just for this very reason.
Also noticed that the oil mentioned is not the specified oil. Probably wouldn't matter too much, but Mercury/Quicksilver now make a pretty decent synthetic blend 25w-40. Much better than the old crap they used to recommend.

 

[Scott06]

That's beyond cheap, it's asinine...

Yep tried to talk sense to him many times. Eventually I suspect it will catch up with him... personally I do my oil and lube annually. My old boat was 25 years and still kicking.