switching from 10w40 to sae40 in boat engine

[snomaker321]

we have an '83 mercruiser 228 in our boat(same engine as GM 305). My dad has been running 10w40 in it for years but we just noticed it says on it to run sae30. I looked online and they now recommend 25w40(mercruiser brand only makes, $8 a quart). If you cannot get that, they recommend sae40, then sae30, and then 20w40 i believe.

Would there be any problem switching from the 10w40 to straight 40? We'll probably use Rotella t.

I just wanna make sure. thanks

 

[cammeddrz]

you will be absolutely fine

 

[strvger]

well, 1983 to 2010 and no problems? don't fix what isn't broken. i'd keep using the 10W40. factory always wants you to use their brand so they charge you an arm and a leg for it. i believe the multiviscosity you have been using all these years will be better than any straight weight oil, as long as it is a good name brand. just my $.02.

 

[snomaker321]

well, 1983 to 2011 and no problems? don't fix what isn't broken. i'd keep using the 10W40. factory always wants you to use their brand so they charge you an arm and a leg for it. i believe the multiviscosity you have been using all these years will be better than any straight weight oil, as long as it is a good name brand. just my $.02.

i thought this also, although we bought the boat in '86 and he thinks he used to use 10w30 at some point. We're not using their brand, its wayy to expensive, but straight 40 is what is now otherwise recommended for the engine. I think the problem with the multiviscosity was that some additives arent good in the marine environment and the engines run cooler. Plus its only used it warm weather.

Thanks guys, I guess we'll give the 40 a try

 

[cammeddrz]

my mantra has always been that "oil is like religion, everyone feels strong enough about it to argue, and everyone thinks their belief is the only right one.........."

so i do agree with the attitude of "stick with what works", but also i know that the bearings in older engines have a much higher zinc content so the actual additievs in the oil matter less than on a new vehicle, and the engines themselves are built with looser tolerances so visosity is less of an issue than it is on newer vehicles

 

[Hopman]

my mantra has always been that "oil is like religion, everyone feels strong enough about it to argue, and everyone thinks their belief is the only right one.........."

so i do agree with the attitude of "stick with what works", but also i know that the bearings in older engines have a much higher zinc content so the actual additievs in the oil matter less than on a new vehicle, and the engines themselves are built with looser tolerances so visosity is less of an issue than it is on newer vehicles

My daddy always taught me that "the WRONG oil is always better than NO oil."

He's right. I've run into a few times when I've needed an extra quart in a diesel that recomended 15w40, but all I could find was 5w30. Better than nothing.

 

[cammeddrz]

My daddy always taught me that "the WRONG oil is always better than NO oil."

more true words have never been spoken

 

[Hopman]

more true words have never been spoken

My dad has also taught me this: "A GREAT day at work is when nobody gets hurt and you don't break anything. A GOOD day is when nobody gets hurt."

That's how I judge my days at work. Any day you & your coworkers come home with all the parts you started with is a good one.

Another thing I live buy: "Parts can be replaced. People can't." Better to break something (even if it will be a PITA to fix) than get somebody injured.

 

[JohnnyO]

In an '83 motor I would run diesel-rated 15w-40. Has more zinc which is better for flat tappet lifters. Newer automotive oils have less zinc so as not to frag the catalytic converters, which you don't have on a boat anyway.

 

[Peregrine]

In an '83 motor I would run diesel-rated 15w-40. Has more zinc which is better for flat tappet lifters. Newer automotive oils have less zinc so as not to frag the catalytic converters, which you don't have on a boat anyway.

I'd second that...

 

[kimcrwbr1]

I would stick with the 10W40 and use the motorcraft filter. Boat motors are always under a load there is no coasting down hill even tho it is runnig cool it is working hard all the time and it is still running after all these years your best bet is to change it more often and always use a high quality filter. When you think of it what percentage of the operation of the engine actually goes to prevenative maint the few bucks per quart dont add up to nothing kinna like cleaning a three dollar pcv valve it is really kinna senseless when your out on the water and that engine can save your life.

 

[scotts90ranger]

enjoy having your no cat boats while you can, in 2012 they will be required, they are now in California... believe me I work for Kodiak Marine (our website is way behind or I'd show pictures of what we have... if you want to look it's http://kemequipment.com) which is namely for jet boats but right now we have 350's and 6.0L's with cats, doesn't hurt performance... at full throttle they still run 12.5:1 AFR like they should...

anywho... as for oil, I agree with the non roller statement, on the new engines we sell we just use the Napa brand 10W40 that we get in 55gal drums...

 

[snomaker321]

Well we decided on the 40, he chose now to mention to me that the oil pressure has been on the low side lately.

 

[kimcrwbr1]

Sounds like it imght be getting a little weak check the compression and put a vacuum guage on it. As long as the compression is even and the vacuum holds steady at an idle you should be alright but that will tell you the overall health of the engine. It is never cheap or easy tearing into a older boat motor alot of rust and corrosion to deal with. I would say run it till it pukes but for a boat fix it before it does they seem to break exactly when you don`t want it to. GL and be careful keep a close eye on the oil pressure.

 

[Hopman]

It is never cheap or easy tearing into a older boat motor alot of rust and corrosion to deal with.

BOAT: Bust Out Another Thousand
Boat: a hole in the water you pour money into.