5L Mercruiser...synthetic oil?

seratime

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Dec 23, 2014
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Yo Capn's all...My 5L 305 Mercruiser has about 350 hours on it. The boat was used when I bought it but runs like a top. I do not know if it was properly maintained or cared for mechanically however they did keep it looking like new cosmetically.

Do any of you recommend a synthetic or blended oil as a good choice to baby a remanufactured engine in order to get a long life from it. If so, what name brand and weight of oil do you use. I am in a warm climate during the boating season so I don't think I need the really thin stuff.

Fred
 

alldodge

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Oh goodie another oil thread :popcorn: :D

Synthetic is better then petroleum oils, that said no modern engine has failed due to the oil being used, it's always due to lack of maintenance or defect. I use straight 40W because I do not start the boat up if I need a jacket
 
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seratime

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Dec 23, 2014
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Thanks...Its just that I was told by a mechanic to go to a synthetic or blend on the aging 4.3 chevy in my truck...this set me to pondering. There may be some merit to it or ...nahhhh..
 

HT32BSX115

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Do any of you recommend a synthetic or blended oil as a good choice to baby a remanufactured engine in order to get a long life from it.
Fred

Howdy Fred!

Ahh, in a word, No.................If you don't want to use whatever Merc recommends, you can essentially run about any suitable oil as long as you change it at the end of the season before winter layup. It's really not all that critical.

Synthetic oil is really good when the water is frozen solid..........probably not doing a lot of boating when that happens.......

Cheers,


Rick
 

Volphin

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I agree with Rick. However, I just use the Quicksilver stuff.
 

HT32BSX115

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Dec 8, 2005
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I agree with Rick. However, I just use the Quicksilver stuff.

A friend of mine gave me 2 gallons and a qt of Quicksilver 25W-40 oil so for the first (and last) time, my next oil change will with it! [woo-hoo!]:facepalm:
 
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