Oil change interval

Mercruiser 5.7, 250 hours on motor. Oil was changed last April and had 3 lake trips last year, totaling 7 days. I brought the boat out to run it on the hose and the oil still looks new. Will it be ok to run it again this season or is it highly recommended to change it every season, regardless of how little it was used? If it matters, I live in Arizona and the boat is garaged during the winter.

​Thanks,

Chris

I'm going to be blasted for this for sure, but since you asked the question I'm going to answer it.

As always these are my opinions, and the caveat is "garage kept".

I used to change the oil in my car every 3000 miles. Grandpa said that was too long - he changed at 1000 miles. Oils are better today, plus my cars now have an oil life monitor. The monitor has me change at about 9000 miles on my car, or about every 9 months.

My dedicated boat towcar puts on about 300 miles a year. The launch ramp is 1 mile from the house. Last time I changed the oil I saw the tech collecting it in bottles, rather than the disposal pan. When I inquired he said it was too clean to discard - he was going to put in in his pickuptruck.

My I/O boat oil gets changed every 100 hours - which in recent years has been every 3 years. Even then when i change it the old oil still looks golden color. Moisture, acid, condensation, yeah right - the boats and cars are in a dry garage. I firmly believe the oil companies have had us bamboozled all these years just to sell more oil.

FWIW last year I ran mine about the same, maybe 20 hours, so I do not plan on changing the oil this spring. I did drain about a 1/2 cup of oil from the outdrive to check for water and metal shavings. All was OK, so will top it off and run it this season.

My boat is stored inside also and some years it gets used more than other years. So I change the oil when it becomes discolored or every other year. There have been some years that it has been changed yearly when it gets a lot of use. Just going to depend on what your comfortable with and how much do you believe in all the write ups. I do change out the outdrive lube each year just to be sure no moisture is in there, only takes a small amount and is easy to do. Just my two cents anyhow......

JimS123 said:

I firmly believe the oil companies have had us bamboozled all these years just to sell more oil.

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Do a used oil analysis... They are relatively cheap, and they are the best gauge of your oil change interval's. Some vehicles like 3000 miles, some can go 10,000. Without the analysis, you have no idea. Same goes for a boat engine.

Who performs used oil analysis?