1995 OMC 5.0L motor oil question

ggundersen3

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I have a '95 Four Winns Horizon 190 with an OMC 5.0L. The previous owner said he used 10W30 motor oil. I was always under the understanding that straight weight SAE 30 should be used in marine I/O engines. Will either one be OK to use?
 

racerone

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I would use 25-40.----Mercruiser markets it for theirs.----Same engine.
 

QBhoy

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You’d be amazed at the number of different oil specs suggested for identical engines like this, used by VP, Yamaha, merc, OMC to name a few.
 

Lou C

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OMC recommended straight 30, Merc recommended straigth 30 or 40, 20/40 or 20/50, then came out with their own 25/40. Volvo used to recommend a syn 30 then they switched to a syn 10/40. Many use Rotella or Delo 15/40 in their inboards, it is a good bit cheaper than the Merc oil. Watch your oil pressure at idle after coming off plane, if it is 20 psi or better, the oil you are using is probably good enough, if its lower I'd use a higher viscosity oil. I have used straight 30, 40 and the Merc 25/40 all with more or less the same results. The 10w-- oils can be used if you have an engine oil cooler, however, most I/Os don't and I think those oils can thin out under marine inboard use.
 

QBhoy

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OMC recommended straight 30, Merc recommended straigth 30 or 40, 20/40 or 20/50, then came out with their own 25/40. Volvo used to recommend a syn 30 then they switched to a syn 10/40. Many use Rotella or Delo 15/40 in their inboards, it is a good bit cheaper than the Merc oil. Watch your oil pressure at idle after coming off plane, if it is 20 psi or better, the oil you are using is probably good enough, if its lower I'd use a higher viscosity oil. I have used straight 30, 40 and the Merc 25/40 all with more or less the same results. The 10w-- oils can be used if you have an engine oil cooler, however, most I/Os don't and I think those oils can thin out under marine inboard use.
Agree. I’d also throw in that VP not long ago suggested (for your average temps boating) a choice of 30w, 20-50 and 15-50…just to confuse things a little 😂
 

Lou C

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yes we are in the winter doldrums but because you opened up that discussion....
efi vs carbs...
1) running smoothness (esp cold starts) advantage efi
2) parts availability and repair-ability esp if you are over about 60 years or so, advantage carb by far....instead of Volvo's and Merc's NLA B.S. can't get this or that, with carbs you have 3 work-able choices (Quadrajet if you have a good original core, Holley or Edelbrock), many aftermarket parts vendors (my favorites being Cliff's and Quadrajetparts.com), a choice of mechanical or electric pumps (depending on engine year) etc. The thriving muscle car restoration business in the USA has given us these choices, if it were up to Volvo or Merc you'd be SOL, all they want you to do is buy one of their fuel injected cat converter equipped wonders that are fine till you start with the check engine light nonsense...then have fun with that, and parts prices. NO THANKS, I'll stick with proven 60 year old technology. After all the SBC is 66 year old technology!
3) cool factor in appearance (esp if you were raised in the muscle car era) carbs, nothing looks better than a huge 4bbl carb on top of your SBC....
here's some Chevrolet 409 eye candy at my local hot rod shop....dual quads on a 409....she's real fine...
 

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QBhoy

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yes we are in the winter doldrums but because you opened up that discussion....
efi vs carbs...
1) running smoothness (esp cold starts) advantage efi
2) parts availability and repair-ability esp if you are over about 60 years or so, advantage carb by far....instead of Volvo's and Merc's NLA B.S. can't get this or that, with carbs you have 3 work-able choices (Quadrajet if you have a good original core, Holley or Edelbrock), many aftermarket parts vendors (my favorites being Cliff's and Quadrajetparts.com), a choice of mechanical or electric pumps (depending on engine year) etc. The thriving muscle car restoration business in the USA has given us these choices, if it were up to Volvo or Merc you'd be SOL, all they want you to do is buy one of their fuel injected cat converter equipped wonders that are fine till you start with the check engine light nonsense...then have fun with that, and parts prices. NO THANKS, I'll stick with proven 60 year old technology. After all the SBC is 66 year old technology!
3) cool factor in appearance (esp if you were raised in the muscle car era) carbs, nothing looks better than a huge 4bbl carb on top of your SBC....
here's some Chevrolet 409 eye candy at my local hot rod shop....dual quads on a 409....she's real fine...
Lovely. That’s cheers me up Lou. Lovely looking !
 

racerone

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As products get more wires and electronics on them the ability to repair these products goes down.-----Modern manufacturing and corporate policy is-----" it can not be repaired. just buy a new one " ---it seems.
 

Lou C

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the fabled "409" was so famous it rated a song by the Beach Boys circa 1962 and started the factory hot rod era...followed by Mopar's Max Wedge 413
Both had the option of dual quads as in the pic above but back then they were Carters not yet Edelbrocks....

heres the old dual quad vs fuel injection....courtesy of the Beach Boys....
Max Wedge 413 with Dual Quad Carters Vs 327 Sting Ray with Rochester mechanical fuel injection....

 

QBhoy

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the fabled "409" was so famous it rated a song by the Beach Boys circa 1962 and started the factory hot rod era...followed by Mopar's Max Wedge 413
Both had the option of dual quads as in the pic above but back then they were Carters not yet Edelbrocks....

heres the old dual quad vs fuel injection....courtesy of the Beach Boys....
Max Wedge 413 with Dual Quad Carters Vs 327 Sting Ray with Rochester mechanical fuel injection....

I love some American cars, to be fair. Brilliant.
 

Lou C

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When you've grown up watching the like of these street racing up the block from your house (when I lived in NYC, borough of Brooklyn) it makes an impression that is life long. Nothing quite gives you that same feeling. And for years we used to go to Raceway Park in Englishtown NJ for the yearly Supernationals to see the top fuel and funny cars race as well as the pro stock cars. Sadly it closed 3 years or so ago....
 

QBhoy

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When you've grown up watching the like of these street racing up the block from your house (when I lived in NYC, borough of Brooklyn) it makes an impression that is life long. Nothing quite gives you that same feeling. And for years we used to go to Raceway Park in Englishtown NJ for the yearly Supernationals to see the top fuel and funny cars race as well as the pro stock cars. Sadly it closed 3 years or so ago....
Amazing Lou. I’m convinced I should have been born across there, instead of a very conservative U.K., in terms of cars. As you’ll know, most cars here have small cc engines. Occasionally someone will make something outrageous with a V8…but not often enough, I’m afraid. I suppose on the upside…it makes the appeal of my wee boat all the better. When she starts up at the slipway or marina…very few people would have heard anything like it before. Big GM V8’s and their sound will be common place over there. Here, they just aren’t a thing in a car. Never have been.
 

Lou C

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That's why many Americans can't stand over-regulation/taxation myself included. Remember the Beatles song? Taxman? They put it well way back when.
You have had some really interesting and cool cars over in the UK, but goverment taxation keeps them out of the hands of most people. That's why till the end of my driving days there will be at least one V8 in my driveway, and when/if I repower this boat, it will probably be a V8. You can't get new marine V6s inboards (old style) any longer anyway. Nowadays I am partial to the modern Gen III Chrysler Hemi. I drove a '15 Challenger Scat Pack with the 392 cu in (6.4 liter) Hemi + ZF/Chrysler 8 speed auto and it was lightening fast. Gotta have one! 1st pic is the one we drive, 2nd is the late model 392 underhood (swapped into a Wrangler believe it or not!) 3rd is the classic1966 426 Hemi V8 with dual quads, last is my 5.7 Hemi with Mopar cold air intake, in my 07 Grand Cherokee.
PS Chrysler built the original Hemis back in the early 50s and then switched to the 413 Wedge engines because they were cheaper to build. Then in 1964 they needed a secret weapon to beat Ford in NASCAR and brought back the Hemi now in 426 cu in (7 liter) form. But they were not actually selling it in street cars. They won a lot of races but the director of NASCAR pitched a fit and told them it was outlawed and ChryCo sat out the 1965 season. Which was boring because Ford won most of the races. Legend has it that the director of NASCAR asked the head of ChryCo to bring it back to street cars to make it legal, which he did and that's why you could buy the 426 street Hemi from 1966-1971. It is still the basis of all top fuel dragsters and funny cars. By the way the Jensen Interceptor in the UK came with a Chrysler 383 and 440 and TorqueFlite auto trans, some even came with the Fergerson all wheel drive system....
 

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QBhoy

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That's why many Americans can't stand over-regulation/taxation myself included. Remember the Beatles song? Taxman? They put it well way back when.
You have had some really interesting and cool cars over in the UK, but goverment taxation keeps them out of the hands of most people. That's why till the end of my driving days there will be at least one V8 in my driveway, and when/if I repower this boat, it will probably be a V8. You can't get new marine V6s inboards (old style) any longer anyway. Nowadays I am partial to the modern Gen III Chrysler Hemi. I drove a '15 Challenger Scat Pack with the 392 cu in (6.4 liter) Hemi + ZF/Chrysler 8 speed auto and it was lightening fast. Gotta have one! 1st pic is the one we drive, 2nd is the late model 392 underhood (swapped into a Wrangler believe it or not!) 3rd is the classic1966 426 Hemi V8 with dual quads, last is my 5.7 Hemi with Mopar cold air intake, in my 07 Grand Cherokee.
PS Chrysler built the original Hemis back in the early 50s and then switched to the 413 Wedge engines because they were cheaper to build. Then in 1964 they needed a secret weapon to beat Ford in NASCAR and brought back the Hemi now in 426 cu in (7 liter) form. But they were not actually selling it in street cars. They won a lot of races but the director of NASCAR pitched a fit and told them it was outlawed and ChryCo sat out the 1965 season. Which was boring because Ford won most of the races. Legend has it that the director of NASCAR asked the head of ChryCo to bring it back to street cars to make it legal, which he did and that's why you could buy the 426 street Hemi from 1966-1971. It is still the basis of all top fuel dragsters and funny cars. By the way the Jensen Interceptor in the UK came with a Chrysler 383 and 440 and TorqueFlite auto trans, some even came with the Fergerson all wheel drive system....
Jeez, you’re a lucky man. Makes me want to emigrate right now ! Is that 6.4 derived from a 6.2 383 stroker ? Amazing looking things.
 

Lou C

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The Chrysler Hemis have had a few series....one of first Hemis though was not an automotive engine, it was an experimental inverted V16 built for Republic's P-47 fighter plane (normally powered by a Pratt & Whitney R-2800) to push the piston powered prop engine envelope these never made it into production but were reportedly clocked at 505 mph. These beasts were built at Republic's Farmindale Long Island plant from 1941-1945, we used to live near there and was able to drive through the huge compound before it shut down in 1987. When jets came on the scene, no more need for piston powered fighters but they kept experimenting with Hemi head combustion chambers....
Gen 1 was early 50s, then replaced with the Wedge series (413, later 426, these became the first factory super stock drag cars)....
Gen 2 was 1966-1971 426 cu in (7 liters) Hemi was dropped after 1971, they continued with the wedge series 383 and 440 engines....
Gen 3 started in 2003, 5.7 liters, then up to 6.1, then 6.4
These engines are very common here, used in Dodge Ram pick ups extensively.
I'm a Jeep guy I've driven a number of Jeeps with the very good Pentastar 3.6 liter V6 but the Hemi in a Grand Cherokee is just in a different league.
 

QBhoy

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The Chrysler Hemis have had a few series....one of first Hemis though was not an automotive engine, it was an experimental inverted V16 built for Republic's P-47 fighter plane (normally powered by a Pratt & Whitney R-2800) to push the piston powered prop engine envelope these never made it into production but were reportedly clocked at 505 mph. These beasts were built at Republic's Farmindale Long Island plant from 1941-1945, we used to live near there and was able to drive through the huge compound before it shut down in 1987. When jets came on the scene, no more need for piston powered fighters but they kept experimenting with Hemi head combustion chambers....
Gen 1 was early 50s, then replaced with the Wedge series (413, later 426, these became the first factory super stock drag cars)....
Gen 2 was 1966-1971 426 cu in (7 liters) Hemi was dropped after 1971, they continued with the wedge series 383 and 440 engines....
Gen 3 started in 2003, 5.7 liters, then up to 6.1, then 6.4
These engines are very common here, used in Dodge Ram pick ups extensively.
I'm a Jeep guy I've driven a number of Jeeps with the very good Pentastar 3.6 liter V6 but the Hemi in a Grand Cherokee is just in a different league.
Love learning more about these things Lou. Her family live in Canada. We visited a few years ago now. Her cousin let me use his Dodge Ram hemi. What a thing, I thought. Just wouldn’t be a thing such as this over here. His friend had a truck with a big Cummins in it. Can’t remember the details..but she was tuned up that much, the black smoke was unreal. But so was the power in it. Rather the hemi though. I’ve always had quite quick cars over here…but usually cars here make their power from quite small displacement and high revving engines. Just not the same, I think. Like I say…I was born in the wrong country, haha. At least my v8 side exit boat keeps me entertained, if I can’t have one in a car. Although I must admit, I still love the sound from my old classic cvx16 with her old V6 merc 2 stroke.
 

PITBoat

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Yeah it has been rather slow...

I'll take a '66 2-Dr Bel Air or Biscayne with a 427, thanks.

I put 20W-50 in my old worn out 4.3L (truck) once to see if it'd slow the oil useage, and it made it run hot, to the point of boiling the coolant in the overflow. It was even one of the recommended weights in the owner's manual.

I'm using the 15W-40 stuff in the boat based on the recommendations here, but I'd be perfectly comfortable with straight 30 weight. I expect my engine will outlast the rest of the boat anyway, so it doesn't matter too awful much, lol.
 
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