Need recomendations on oils for mercruiser.

Question:

Correct, but how does one make oil achieve 40 wt viscosity when warm, but still flow like 10 wt when cold? Here’s how: by taking base 10 wt

<SNIP What’s realy interresting about this iol controversy is that Merc has gone to multi-vis oil. The Merc oil you get at you local dealer is 10W-40 I believe. They claim the real culprit in "car" mutli-vis is the polymer is water soluble and deteriates when it comes in contact with water vapor. Their polymer doesn’t! Maybe, maybe not but since their oil is within 20% of the price of normal oil for most people it’s smart to use the Merc. Oil. BTW, I use 15W-50 Mobil One in a 454 Magnum. — Mark Whatman http://home.att.net/~mwhatman

Response:

I agree 100% about not extending the oil changes. My engine builder recommends changing every 20 hours whether it be synthetic or not. BTW, I’ve run 40W when they were Mercs, and currently run, by the builder’s recommendation, 50W racing oil.

Garry, your engines are not run-of-the-mill engines used by most recreational boaters. Not everybody who reads your comments is going to know or remember that, so you should remind them. There’s a possibility that some rec.boater is thinking he should go get some straight 50 weight oil, because he read in your post that an engine builder recommended it, and should he carry through on it, he may suffer bearing failure as a result. Other folks have commented on using 10W30 or 10W40 in marine engines. DON’T DO IT. Use what the book, or more recent service bulletin says. Multiweight automotive oil breaks down much more quickly in a marine application. The exception would be straight synthetic, which achieves its flatter temperature characteristic with chemistry different from petroleum oils. Sure, the marine engine starts at the water temperature. But the car engine starts at the air temperature, which can be way below the temperature at which water turns hard. That’s why we have 5W30, 10W30, etc., for those reallllyyyy cold days. Furthermore, we want to start our cars at below freezing, and take off 10 seconds later. We tend not to do that with marine engines, but warm them up a bit. So you can get away with the straight weight oil in the marine engine. MerCruiser has an oil something like 25W40, actually a blend of straight 25 wt and 40 wt, not quite the same thing. You neither want an oil too thick nor too thin. Go with the factory recommendation. When someone says "I’ve used X with no problems" what they really mean is "no problems YET." You can’t be sure. — —

Response:

first. If you are worried about high temps, 20W-50 is a better high temperature oil than 40W. Your mechanics are wrong about 10W-40. It has the same viscosity at running temperature as 40W, but has the added advantage of lower viscosity when cold. This helps reduce "start-up" engine wear. Maintenance people will not tell you stuff that causes you to spend money somewhere else. If they sell the oil, that oil is _definitely_, in their opinion, going to be the oil you should use. In reality, you can go to K-mart and buy 10W-40 oil. If you change it as scheduled, you will not have any problems. Bob K

One of the better sites that I found had a great article on Synthetic oil and crude. Worth reading if you want to know a little about the blood in your engines. The entire article is available at http://www.vtr.org/maintain/oil-synthetics.html Here’s a small snip where they talk about viscosity improvers and the fact that VIs wear out under shear stresses. VI improvers are designed to help an oil’s viscosity/temperature performance. Remember that at high temperatures, an oil’s viscosity drops. If it drops too low, we lose film thickness, and are in big trouble! The viscosity index (VI) is a measurement of how an oil’s viscosity changes with temperature, compared to reference oils. The higher the number, the better. VI improvers are polymer compounds with interlocking structures (polymers are long chain molecules). Because these chains are interlocked, they don’t move as easily at high temperatures and resist viscosity loss. Unfortunately, they don’t necessarily contribute anything to lubricity, and in fact begin to wear out under shear stresses. As they wear, the oil’s VI deteriorates, and we’re left with the old VI improver, which has to be held in suspension. This is another reason to change your oil frequently! The VI improver’s sensitivity to high shear stress is significant in that if the shear stress is high enough, the oil may experience either a temporary or permanent loss of viscosity! Garry Heon

Response:

Correct, but how does one make oil achieve 40 wt viscosity when warm, but still flow like 10 wt when cold? Here’s how: by taking base 10 wt oil, and adding "viscosity index enhancer" polymers that uncoil and lenghten when warm, thereby increasing the warm viscosity above the base 10 wt up to that of an equivalent warm straight 40 wt. You don’t have a real 40 wt, but something that when new, performs much like a 40 wt when warm. Then, under severe loading, the viscosity index enhancers break down and you are left with oil that’s much thinner than you had before. NOT GOOD. Auto engines get away with it because their stresses are momentary compared to marine engines. This is petroleum oil, by the way. Synthetics can use different chemistry and suffer less "viscosity breakdown" as a result. This helps reduce "start-up" engine wear.

Ask yourself just how cold that marine engine is, realistically, when you start it. How cold is an automobile engine when you start it? 10W30 and 10W40 are meant for engines that are likely to encounter temperatures well below freezing. Do you need this property in an oil for a marine engine? And back to the recommendation for 20W50. Are you aware that too thick an oil will not flow fast enough through the passageways to lubricate all the parts? Are you aware that a film of oil at too high a viscosity will "tear" under high shear and fail to hold moving parts away from each other? Ask yourself just how hot the oil in that marine engine is, really, with a coolant thermostat set to 140. Your car engine runs its block around 180 or higher, with 5W30 or 10W30 oil. (Oil temperature is the better indicator of your oil’s operating environment, obviously.) SO, thicker is not always better. To drive the point home, in my youth I refilled a Briggs&Stratton with 20W50. That motor was designed for straight 30 wt and had run fine for 20 years on the stuff. I figured that it was nice and limber from all the hard use and could take thicker oil. The 20W50 was too thick and seized it in only a few minutes use. You should seriously know what you’re doing before you use oil that is thicker or thinner than recommended by the factory or competent service/engineering personnel. Maintenance people will not tell you stuff that causes you to spend money somewhere else. If they sell the oil, that oil is _definitely_, in their opinion, going to be the oil you should use. In reality, you can go to K-mart and buy 10W-40 oil. If you change it as scheduled, you will not have any problems.

You must have experience with many different marine engines run on 10W40 to make this general recommendation. Can you tell us how long you ran them without "any problems"? — —

Response:

I have a MerCruiser 230 (305 V8) and my manual calls for straight #40 oil (their brand of course, " Quicksilver"). As an alternative they suggest 20-50. In any case, these engines work Very hard and at high temps. The mechanics that I have talked with have suggested sticking with the straight #40 oil (although, with the exception of Quicksilver, I have found it a bit difficult to find ). They have told me that 10-40 is simply not good enough and that oil pressure will sometimes drop if you use this oil. I know that there will be lots of folks who will argue with this, but my experience is that the maintenance people are correct. Hope this helps !

What’s wrong with simply using Mercury’s own oil (Quicksilver)? I used it in my 330 Sea Ray Express with twin 7.4 Mercs. I simply assumed that if Mercury Marine recommended it, it should work well. It obviously did, as I had no problems. Oil is relatively cheap, compared with the cost of a rebuild. Synthetics have great properties, but ask a Mercury-trained mechanic first if your engine is broken-in well enough first. Jeff

Response:

- Hide quoted text — Show quoted text – I have a MerCruiser 230 (305 V8) and my manual calls for straight #40 oil (their brand of course, " Quicksilver"). As an alternative they suggest 20-50. In any case, these engines work Very hard and at high temps. The mechanics that I have talked with have suggested sticking with the straight #40 oil (although, with the exception of Quicksilver, I have found it a bit difficult to find ). They have told me that 10-40 is simply not good enough and that oil pressure will sometimes drop if you use this oil. I know that there will be lots of folks who will argue with this, but my experience is that the maintenance people are correct. Hope this helps ! What’s wrong with simply using Mercury’s own oil (Quicksilver)? I used it in my 330 Sea Ray Express with twin 7.4 Mercs. I simply assumed that if Mercury Marine recommended it, it should work well. It obviously did, as I had no problems. Oil is relatively cheap, compared with the cost of a rebuild. Synthetics have great properties, but ask a Mercury-trained mechanic first if your engine is broken-in well enough first.

If you are worried about high temps, 20W-50 is a better high temperature oil than 40W. Your mechanics are wrong about 10W-40. It has the same viscosity at running temperature as 40W, but has the added advantage of lower viscosity when cold. This helps reduce "start-up" engine wear. Maintenance people will not tell you stuff that causes you to spend money somewhere else. If they sell the oil, that oil is _definitely_, in their opinion, going to be the oil you should use. In reality, you can go to K-mart and buy 10W-40 oil. If you change it as scheduled, you will not have any problems. Bob K

Response:

Use only straight 40 w in the motor. Use only MerCruiser Hi Performance Drive Oil.Use only 10w30 in the trim pump,This does not need changing .Marine engines run much cooler then do car engines. Heavy oil is needed because the marine engines have super duty oil pumps and normally have 4-bolt main bearings. In other word Truck like duty motors.

Response:

I have talked to many mechanics about this, and they all say stay away from synthetic….you need to chug the oil to frequently anyways. The lower unit Im not so sure on, but I cant see an advantage of going to a synthetic……20hrs is the break-in for the engine and drive Dave – Hide quoted text — Show quoted text – Hi all. I just bought a second hand. It’s a 21′ Maxim with a 4.3 V6 mercruiser I/O. It only has 40 hours on the engine. I have spend about 1/2 hour in it test driving it, but I would like to change all the oils. Currently I am thinking about going to synthetic oils (motor and lower). I was wondering if anyone knows or had an opinion on the following: a) How long is break-in on a Mercruiser engine and drive?. I have a MerCruiser 230 (305 V8) and my manual calls for straight #40 oil (their brand of course, " Quicksilver"). As an alternative they suggest 20-50. In any case, these engines work Very hard and at high temps. The mechanics that I have talked with have suggested sticking with the straight #40 oil (although, with the exception of Quicksilver, I have found it a bit difficult to find ). They have told me that 10-40 is simply not good enough and that oil pressure will sometimes drop if you use this oil. I know that there will be lots of folks who will argue with this, but my experience is that the maintenance people are correct. Hope this helps ! Al

Response:

I switched to the semi-synthetic 15-50’s and have been happy with them. It’s cheaper than full synthetic. You sould not extend oil changes in boats so synthetic gets expensive. Some prefer to change every 50 hours.

Response:

Yea, but your rolling in the bucks, go for the full synthetic. Let’s $840 a year for oil. I run 15W-50 Mobil 1 in a relatively stock Merc Magnum, I go ~50 hrs between changes and the only side effect is a lighter wallet. water temp dropped 5 deg at WOT due primarily to less friction and the pressure runs about 5 lbs higher at cruise and hot idle. It’s less sensative to heat then petroleum based oils as per GM. — Mark Whatman http://home.att.net/~mwhatman

Response:

- Hide quoted text — Show quoted text – I agree 100% about not extending the oil changes. My engine builder recommends changing every 20 hours whether it be synthetic or not. BTW, I’ve run 40W when they were Mercs, and currently run, by the builder’s recommendation, 50W racing oil. Garry, your engines are not run-of-the-mill engines used by most recreational boaters. Not everybody who reads your comments is going to know or remember that, so you should remind them. There’s a possibility that some rec.boater is thinking he should go get some straight 50 weight oil, because he read in your post that an engine builder recommended it, and should he carry through on it, he may suffer bearing failure as a result.

I guess I should really be much more careful. The clearences in the motors were set up for 50W. Thanks for pointing that out. Other folks have commented on using 10W30 or 10W40 in marine engines. DON’T DO IT. Use what the book, or more recent service bulletin says. Multiweight automotive oil breaks down much more quickly in a marine application. The exception would be straight synthetic, which achieves its flatter temperature characteristic with chemistry different from petroleum oils.

This is really good advise, I looked carefully before selecting a 50W oil for the new motors. There was alot of research available on mulit- grade oils that I had to weed through trying to find what I was looking for. snip away with the straight weight oil in the marine engine. MerCruiser has an oil something like 25W40, actually a blend of straight 25 wt and 40 wt, not quite the same thing.

Is that how they do it??? Figure this, I hate to bring up another dead thread. My oil temp, after the HUGE oil cooler is less than 130 degrees F. I know I do have some oil temp since the filter gets plenty hot. Currently don’t know what that temp is but will find out this weekend since I’ve install oil temp senders before the cooler. Again I talked with the builder and he wants the oil cool going to the bearings. He asked if I see any condensation buildup, I said no. He said then why are you worried. He also stated that condensation buildup in oil usually happens when you run a low water temp with a higher oil temp. Makes sense to me, my water temp on the new motors is the same as the old motors, 110 degrees F. You neither want an oil too thick nor too thin. Go with the factory recommendation. When someone says "I’ve used X with no problems" what they really mean is "no problems YET." You can’t be sure.

Can’t argue with that. As always Marcus, a pleasure. Garry Heon

Response:

Hi Michael, The engine is already broken in at 40 hours. Use a high quality major brand motor oil as the engine will take a lot more stress than a typical car engine. I try to use ‘SJ’ rated oil. I would use Merc Quicksilver lower gear lube. They make it in ‘Premium’ and ‘High Performance’ flavors. Take a look in your manual if you have one or call a Merc dealer if you don’t. Most of the newer drives (like the Alpha) call for the ‘High Performance’ lube. Be sure to change you motor oil as specified (usually 100 hours) and change your lower gear lube every year (unless you’re putting more than 200 hours a year on it). Best of luck and enjoy your new boat. Les Lampman – Hide quoted text — Show quoted text – Hi all. I just bought a second hand. It’s a 21′ Maxim with a 4.3 V6 mercruiser I/O. It only has 40 hours on the engine. I have spend about 1/2 hour in it test driving it, but I would like to change all the oils. Currently I am thinking about going to synthetic oils (motor and lower). I was wondering if anyone knows or had an opinion on the following: a) How long is break-in on a Mercruiser engine and drive?. b) What weight oil should I use in that engine? c) What is a good weight to use in the lower unit. d) Any recommendation on a brand to use in marine engines? (Looking at mobil-1). e) How had is it to change the fluid in the power trim? I there a reason? Currently I would like to use Mobil-1 10W-40 in the engine. Mobil-1 seems to have as good a reputation as Amsoil and is priced at $4/quart as appeased to $6/quart for Amsoil. I would like to run the 40 weight because I was told that marine engines seem to run hot since they are typically pulling a big load at high RPMs. The only problem I have is that Mobil does not seem to make Mobil-1 in 10w-40. As for the lower unit, I don’t have a clue. Please let me know if you can shed some light. Thanks for everyone’s time….

Response:

I just bought a second hand. It’s a 21′ Maxim with a 4.3 V6 mercruiser I/O. It only has 40 hours on the engine. I have spend about 1/2 hour

<snips Hi Mike: I recently bought a new boat with a 4.3L Merc (you didn’t mention if yours is carb or EFI, by the way. Mine’s carb.). Anyway, I bought the factory "Maintenance Procedures Manual" (about $18 total) and highly recommend it. It definitely has answers to all of your questions, plus contains reference data and detailed sections on winterizing, etc. My manual is with my boat (currently far away), otherwise I would get all of your answers from the manual. One thing I do remember is the break-in schedule (since I’m still breaking in my baby motor!) :) The total break-in time is 20 hours. The first 10 hours "not to exceed 75% full throttle", plus other standard break-in guidelines such as varying throttle settings frequently, not running at idle too long, etc. The second 10 hours you can have "brief full throttle operation". So, your 40-hour motor is definitely fully broken in. Happy boating, Cameron

Response:

a) How long is break-in on a Mercruiser engine and drive?.

The 40 on it now is pretty well it, typically 50 hrs.. b) What weight oil should I use in that engine?

Seriously, what the manufacturer recomends! Usually 10-30 in cooler climates and 10-40 in warmer although sometimes they call for a single weight like a streight 30 weight. c) What is a good weight to use in the lower unit.

Almost always 90 weight gear oil is called for but almost always you are best to stick with merc oils for this! A good synthetic is expensive but a great choice because they usually shun water better should a few drops find their way in.. d) Any recommendation on a brand to use in marine engines? (Looking at mobil-1).

Any good brand, change interval and grading would be more important then brand (assuming you don’t use some weird off brand) e) How had is it to change the fluid in the power trim? I there a reason?

None unless there is water in it and much more difficult to change completly. If it had huge hours on it, like 500, then I would change the trim oil (and power steering fluid) otherwise leave it be. Currently I would like to use Mobil-1 10W-40 in the engine. Mobil-1 seems to have as good a reputation as Amsoil and is priced at $4/quart as appeased to $6/quart for Amsoil. I would like to run the 40 weight because I was told that marine engines seem to run hot since they are typically pulling a big load at high RPMs. The only problem I have is that Mobil does not seem to make Mobil-1 in 10w-40. As for the lower unit, I don’t have a clue.

Again, NEVER use a motor oil in the lower unit. It is always a high viscosity gear oil used, #90 or sometimes higher. As for marine engines running hotter? Bull! They definatly run harder, typically 60% throttle compared to 5% in a care, however most marine engines run at 165 deg compared to a car at 190 or so. Marine engines also rarely see 0 deg starts, dusty grimy conditions or the intense under hood heat that a car can. On the flip side, marine engines see much more throttle, more often full throttle starts, often long spells of idling and almost always higher rpm;s.. Also keep in mind that in a marine engine, the start temp is always condsidered the lake temp, not the air temp. If you boat in water that is 65 deg or colder, I believe they classify that as a cold start, wanting 10-30. On the other hand, most of todays synthetics handle cold starts better allowing for a higher visc oil.. Greg.. – Hide quoted text — Show quoted text – Please let me know if you can shed some light. Thanks for everyone’s time….

Response:

Hi all. I just bought a second hand. It’s a 21′ Maxim with a 4.3 V6 mercruiser I/O. It only has 40 hours on the engine. I have spend about 1/2 hour in it test driving it, but I would like to change all the oils. Currently I am thinking about going to synthetic oils (motor and lower). I was wondering if anyone knows or had an opinion on the following: a) How long is break-in on a Mercruiser engine and drive?. b) What weight oil should I use in that engine? c) What is a good weight to use in the lower unit. d) Any recommendation on a brand to use in marine engines? (Looking at mobil-1). e) How had is it to change the fluid in the power trim? I there a reason? Currently I would like to use Mobil-1 10W-40 in the engine. Mobil-1 seems to have as good a reputation as Amsoil and is priced at $4/quart as appeased to $6/quart for Amsoil. I would like to run the 40 weight because I was told that marine engines seem to run hot since they are typically pulling a big load at high RPMs. The only problem I have is that Mobil does not seem to make Mobil-1 in 10w-40. As for the lower unit, I don’t have a clue. Please let me know if you can shed some light. Thanks for everyone’s time….

Response:

Filed under: Acne

XHTML: You can use these tags: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>

TrackBack URL | RSS feed for comments on this post.

Talking Acne

Real topics from real people all about ACNE