Mercury/quicksilver alternatives

[Whipped500]

Looking for a good quality, cheaper alternative to the mercury/quicksilver 25w-40 semi synthetic and conventional...preferably semi synthetic.

Looking to save (if I can) without sacrificing quality. It's for a stock mercruiser 496 ho 425 hp. This motor calls for 9 qts and I would like to change twice a season, this is why I'm looking for a cheaper alternative. It's probably a waste, but each oc will probably only be 25 hours. I'm trying to be extra prevntive of Fuel dilution and corrosion, so a marine approved oil is what I'm looking for.

I was thinking the mystik JT-4 25w-40 semi synthetic would be good but it doesn't look like my farm and fleet carries it.

I'm sure the 15w40 diesel oils are going to be suggested, but do they have the corrosion protection?

Anybody know about the Sierra oils? I heard that since mercury's patent ran out that the Sierra 25w-40 actually has a better add package than the mercury...any truth?

Thanks

 

[Donald]

Rotella oil. I use Rotella T 15W40 in my Mercruiser. The full synthetic Rotella T6 5W40 is on sale at Walmart. There is also T5 but I forgot what the specs on it are.

I use the T6 in my Cummins diesel and routinely go 18K miles on a change.

 

[philipp10]

your in Illinois so you are in fresh water. Why so much worry over corrosion protection? Honestly, in fresh water you are basically running like a car would see. I mean, up in Minnesota, we get 4 months of rain every 3 days, I doubt your motor will rust. And changing twice a season is crazy unless your really running the hours but to each his own.

 

[DoubleWasp]

Yes, HDEO's have a lot of corrosion protection. Diesels are as vulnerable to corrosion damage as a marine gas engine.

We've been running 100 hours on our 454 Mag's with T6 Syn, and used oil analysis have not shown a penalty.

We've started running VR1 20/50 Syn, and will know soon enough how that is working out. It seems to be a lot more shear resistant than T6 in used oil analysis, but is not nearly as cheap as T6.

 

[Bror Jace]

"I'm sure the 15w40 diesel oils are going to be suggested, but do they have the corrosion protection?"

Yes, the beauty of gas/diesel oils (HDEOs) designed for extended drain intervals is that corrosion protection will be top shelf.

Expect the top HDEOs like Chevron Delo, Pennzoil Long Life, Shell Rotella, etc ... to also be more shear stable than Quicksilver 25W40. I've seen a used oil analysis or two of the MQS stuff (probably here) and I wasn't impressed.

 

[Whipped500]

Are the HDEOs going to be the best alternative to mercury and to save some money? If so, I would really be able to save some money by stocking up even more on Mobil delvac 15w40 when they offer their rebates! I have been getting 5 gal Mobil delvac for my truck for $35/5gal after rebate.

Anybody know anything about the Sierra 25w-40 and how it compares to the Mercury?

How about Mobil 1 15w-50? Heard good things about it, but not sure about corrosion.

Also heard kendall is good but hard to find and not sure on price?

Any 20w-50s that are cheaper and have a good additives package?

Sorry for all the questions but I think oil is cheap insurance. Also, I think there are better quality as well as cheaper alternatives to the manufacturer branded oil. Just trying to use a better product as well as save some money to offset an early OCI.

Thanks again

 

[leroyd92]

When I got my little 3l Mercrusier I was going to go all out on oil cause I knew it was going to be my exploring boat for my local river ect.

After stupid amounts of research I decided to run either Wal-Mart super tech hdeo or something from Shell.

After taking the boat out a few times and realizing its life is either 700 rpm or 3500 rpm I decided to run 1540. I can assure you I'll never buy 2040 simply for price reasons. Especially when ocean mechanics with true (work boats ) run 1540in their engines.

Every boat shop around me said to run it and we have water temps like bath water around here

 

[philipp10]

There seems to be this idea that keeping a boat engine cool is some big feat. It shouldn't be as a boat should be MUCH easier to cool than a car motor. Even if the water is at bath temperature, its still way cooler than trying to cool the coolant of a car thru the radiator with high air temperatures.

 

[SteveSRT8]

Originally Posted By: philipp10
There seems to be this idea that keeping a boat engine cool is some big feat. It shouldn't be as a boat should be MUCH easier to cool than a car motor. Even if the water is at bath temperature, its still way cooler than trying to cool the coolant of a car thru the radiator with high air temperatures.


This is a great point. My boat has an extremely high output 572 in it yet uses a ridiculously tiny little heat exchanger. Water is quite a bit denser than air!

In the old days my boats that just drew water from the river we skied on had issues with over cooling, not over heating...

 

[dlundblad]

Originally Posted By: philipp10
There seems to be this idea that keeping a boat engine cool is some big feat. It shouldn't be as a boat should be MUCH easier to cool than a car motor. Even if the water is at bath temperature, its still way cooler than trying to cool the coolant of a car thru the radiator with high air temperatures.


I agree too. The whole body of water is the coolant reservoir. Assuming the water intake doesn't get clogged with zebra mussels (an issue in some local lakes) or seaweed, you are golden.

 

[bubbatime]

15W40 will be fine, especially with such a short change interval.

 

[DoubleWasp]

I had a thermostat stuck open in one of my boats and it refused to cross 150° Keeping a marine engine cool should never be an issue. If it is, start searching for the problem.

 

[Whipped500]

Since it's going into full swing for boaters, any new eyes or info on a good cheaper alternative to overpriced merc? It seems like it's been covered but wanted to bring it back up since it's more of the boating season now.

Also, is there any foaming problems with running a hdeo? I thought I read on a boating site that a diesel oil can foam because of the higher rpm.

Thanks

 

[FastGame]

No foaming with an HDEO like Rotella, it works in my Kawasaki Concours 14 running many engine gears including trans & drive shaft output. The only foam I've ever seen comes from my mouth after WOT ! haha