Saw this on a boating forum. Someone re-powered and wants to run synthetic after 20hrs but the manual says it`s a no-no. I guess they recommend only a Dino 25-40 and it`s a Chevy small block. This person(and me as well)would like to know why? He only got the standard "do it for the warranty", "Mercury Marine know whats best for their motor",answers,but no real reasons behind this.
New Mercruiser 4.3L 220 HP MPI,Manual Says No Synthetic
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JHZR2
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is that a chevy v-6?
I have the 4.3 v6 in my truck... I havent seen many good UOAs on, say M1 in the auto version.
cant see how it would differ in the marine version.
JMH
I have the 4.3 v6 in my truck... I havent seen many good UOAs on, say M1 in the auto version.
cant see how it would differ in the marine version.
JMH
did you see that on bizarro, I mean iboats, dot com?
simplest thing I can think of is merc sells their brand of oil. They want you to buy it so they can make money. I'm sure there's some effort gone into it to make it a good oil.
Of course they will tell you to use it because it's better, than say "automotive" oil. And why not better than synthetic oil. I'm sure they would say it's marine-grade and uscg approved, probably even meets abyc standards. And to clinch the sale tell you if you want your warranty honored that you must use OUR oil.
Simplest and cheapest thing to do is not tell the service market anything technical about oil, only to use merc 25w-40 and no other oil including synthetic.
I heard merc is coming out with either a synthetic-blend, or synthetic, 4-stroke oil. What does that tell you?
The word "synthetic" has no real meaning anymore in regards to oil. Conventional oil can be labelled synthetic, there are no rules as to how much % synthetic there must be for oil to be labelled as synthetic. Group III oil which is just highly refined petroleum oil, is labelled as pure-synthetic.
I don't know for sure how far into the engine merc goes. But doesn't GM design and build the engine, Merc just slaps on carbs, fuel pumps, andd bastardized ignition systems?
simplest thing I can think of is merc sells their brand of oil. They want you to buy it so they can make money. I'm sure there's some effort gone into it to make it a good oil.
Of course they will tell you to use it because it's better, than say "automotive" oil. And why not better than synthetic oil. I'm sure they would say it's marine-grade and uscg approved, probably even meets abyc standards. And to clinch the sale tell you if you want your warranty honored that you must use OUR oil.
Simplest and cheapest thing to do is not tell the service market anything technical about oil, only to use merc 25w-40 and no other oil including synthetic.
I heard merc is coming out with either a synthetic-blend, or synthetic, 4-stroke oil. What does that tell you?
The word "synthetic" has no real meaning anymore in regards to oil. Conventional oil can be labelled synthetic, there are no rules as to how much % synthetic there must be for oil to be labelled as synthetic. Group III oil which is just highly refined petroleum oil, is labelled as pure-synthetic.
I don't know for sure how far into the engine merc goes. But doesn't GM design and build the engine, Merc just slaps on carbs, fuel pumps, andd bastardized ignition systems?
Yeah, the 4.3 has been a reliable work horse for Mercruiser. 18 to 20 footer boats, usually the 4.3 is an optional engine from the standard work horse 3.0 series. You can run just about anything in that engine and will run like a scolded dog in heat. The only problem they have is the valve guides tend go out after a while and you might start burning a little oil during crankups. Just check the oil from time to time. However, I do like the idea of having oil coated pistons when I crank it up.
We've collectively cracked the code:
Engine marinizer sez--
Only run "our" brand of oil and filters.
I think on these old-style GM powertrain blocks, matching the oil weight to the climate and running conditions is probably best. straight 30 [cooler climate], straight 40 [warmer climate], 20-50, 25-40, 15-40. You'd be doing no real harm with any of these.
There is a published acceptable list of oils by the marinizer. Stay within the lines, and don't worry about warranty problems.
Engine marinizer sez--
Only run "our" brand of oil and filters.
I think on these old-style GM powertrain blocks, matching the oil weight to the climate and running conditions is probably best. straight 30 [cooler climate], straight 40 [warmer climate], 20-50, 25-40, 15-40. You'd be doing no real harm with any of these.
There is a published acceptable list of oils by the marinizer. Stay within the lines, and don't worry about warranty problems.
Ive heard of this elsewhere too. Its funny though. you either have dino oil or synthetic right? So if you use synthetic, therotically superior to dino, whats bad with that? Is merc oil some kind of alien "super oil"? LOL i think not. I use full synthetic (wally world brand) 10w-30 in my 3.0 (GM based) 4 cylinder engine. On 100 degree days, the temp will be at 160-170 and oil pressure at idle is about 30lbs. At WOT about 50lbs, fine with me
Thats pretty weird
I ran synthetic oil castrol in my 1988 4.3 4bbl v6 OMC for... well its 2005 and i just sold it.
changed the oil every season and it alwasy was so clean it was hard to read on the dipstick
it ran smooth and I never had any oil related issue with the engine excpet if you ran her at 4600 rpm or higher for long periods and then have to go thru a no wake zone. the idle would have to be bumped up to maintain 30lbs of oil pressure for a few minutes till everything cooled down.
it was a great little engine
I ran synthetic oil castrol in my 1988 4.3 4bbl v6 OMC for... well its 2005 and i just sold it.
changed the oil every season and it alwasy was so clean it was hard to read on the dipstick
it ran smooth and I never had any oil related issue with the engine excpet if you ran her at 4600 rpm or higher for long periods and then have to go thru a no wake zone. the idle would have to be bumped up to maintain 30lbs of oil pressure for a few minutes till everything cooled down.
it was a great little engine
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