www.iFourWinns.com

Hey guys, I've always been curious about this. In ALL, and I mean ALL of my "other" vehicles, I run full synthentics, and am a sworn believer in them, as my engines are all in excellent condition. I run Mobil1 5w30 in all of my cars, and I use Amsoil 10w40 full synth in my Honda Goldwing.

Just wondering if you guys think running a full synth oil in my marine engine will help it last longer, run smoother, etc? I have a 1990 Four Winns 170 freedom with the 2.3l 4 cyl OMC Cobra in it.

I'd gladly switch it over to full synth as well, if I knew it would be "good" for the engine.

Dan

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1990 Four Winns 170 Freedom, 3.0 OMC Cobra 4 cyl.

I'd say you'd get the same benefits.
Doug

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2003 Four Winns 170 Freedom Cincinnati, Ohio / Cape Coral, Florida

Since I change my oil after every season before winter layup, I have never found a reason to switch to synthetic. Having said this, it may depend on how many hows you run it per season/year. I put on no more than 50-60 hours per season, so, for the last 30 years of boat ownership, the regular blends have done the trick. I currently run Merc 25W-40 in our 4.3 GXi Volvos on the advice of our mechanic.

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"One Moor Time" 2006 288 Vista
"Kalin II" 1995 258 Vista
"Kalin" 1985 Four Winns 215 Santara

It would be a good upgrade.
Ensure whatever you use has a high level of ZDDP, as most synthetic blends now have much lower levels for environmental reasons.
The Mobil 1 15w50 should be ideal.

p.s. From recent research, NMMA oils aren't worth the paper they're written on for corrosion protection.

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2011 Four Winns H180 SS.
Aussie built Mustang 2800.
SOLD - 1997 Four Winns Horizon RS

I saw a tech bulletin from VP that indicated that their newer engines (2008 and up) should use their syn 10w/40, but the older engines can use the gas/diesel rated 15w/40 which gives you a lot more choices, such as Delo 400, Rotella, Mobil Devlac and Pennzoil Marine. So I'd say either the Merc 25/40 or the HD 15w/40 would be good for any older engine.

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88 Four Winns 200 Horizon
4.3 OMC Cobra-4bbl
2002 Walker Bay 10/2012 Suzuki 2.5
2008 Walker Bay 8

1998 Jeep Grand Cherokee 4.0/Selectrac
2007 Jeep Grand Cherokee 5.7 Hemi/Quadradrive II

I used rotella 10w/40 in my last oil change. Got a great deal on it - Mechanic said any decent synthetic or blend in 10w/40 would work.

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2008 Four Winns h180 Bowrider
3.0 Volvo Penta

2013 Dodge Durango HEMI

Great,

thanks for all of the helpful advice. I will run with regular oil for the rest of this season, as that's what is in it, but when I do winterization this fall, I think I'll switch over to a Full Synth.

Dan

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1990 Four Winns 170 Freedom, 3.0 OMC Cobra 4 cyl.

Volvo recommended full synthetic straight 30w until Amzoil stopped making it. I'm a believer too, I even run it in my lawn mower. However, you may be running some increased risk of oil leaks when switching over a 25 year old engine.

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Mike
2005 Four Winns 230/240
VP 5.7GXi/DP
1998 F-150 XLT
Boat Pic

^^^ An old wife's tale.

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2011 Four Winns H180 SS.
Aussie built Mustang 2800.
SOLD - 1997 Four Winns Horizon RS

Actually it's not. It's got to do with dried out seals resulting from sludge buildup. I've seen it myself, a number of times. I realize this is a religious issue with people on both sides, but my eyes don't lie.

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Mike
2005 Four Winns 230/240
VP 5.7GXi/DP
1998 F-150 XLT
Boat Pic

I wouldnt use Syn in that engine; just use either the Merc 25/40 or Pennzoil Marine 15w/40 or the same grade in Delo, or Rotella. These grades have been used extensively in marine inboards.

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88 Four Winns 200 Horizon
4.3 OMC Cobra-4bbl
2002 Walker Bay 10/2012 Suzuki 2.5
2008 Walker Bay 8

1998 Jeep Grand Cherokee 4.0/Selectrac
2007 Jeep Grand Cherokee 5.7 Hemi/Quadradrive II

Not a wife's tale. The gaskets in the older engines were not made for the synthetic oil. They will or can start leaking.

YES!

I would use a **-40w. Marine engines run warmer and the "up to 40w" will not thin out as quickly as 10-30W oil.

Never heard of that. But synthetic oil has been around, for what, 15 plus years.

The first synthetic oils were developed in Germany during the late stages of WW II since the allied bombings destroyed most refineries and cut the oil supplies off.

The first large scale commercially available synthetic was Mobil 1 coming to market in the 70s

A call to the manufacture will tell him weather he can or not. Just because of the reason stated.
When Syhthetic started to become popular people started using it in cars and developed oil leaks.(rear mains-Valve covers)
My buddy has a Silverton with Crusaders in it and he is Synthetic gung ho. I told him this before he wanted to switch over and the manufacture told him noway and for the reasons i stated.