Motor oil...OEM Only?

GReetings again....
I have 5.0l (305) LX Mercruiser, The owners manual says that you MUST use Quicksilver oil, so the question is : Can i use synthetic oil or some other oil, and what is a good weight. Also does anyone know what the LX in 5.0l LX means?

Thanks Jules

Re: Motor oil...OEM Only?

Oh dear god... another oil thread...

Julian, Oil threads are like a locust. We have so many more than we need. Just do a search on oil and you will have reading to last you for about 3 lifetimes.

Use whatever oil you prefer, as long as it meets the manufacturers spec... Complete this sentence with anything you want.. "I use____ and I've never had a problem"...

Generally when there are 2 variants of the same capacity engine Merc will designate them as ...L and ...LX. I guess it started as a 5.0L (as in 'Litre') with a 2bbl carb, and when the 4bbl was added, the X is for 'extra'.... Who knows, it could all be just another marketing ploy. Much like cars are badged.... JMHO

Chris.......

Re: Motor oil...OEM Only?

achris said:

Oh dear god... another oil thread...

Julian, Oil threads are like a locust. We have so many more than we need. Just do a search on oil and you will have reading to last you for about 3 lifetimes.

Use whatever oil you prefer, as long as it meets the manufacturers spec... Complete this sentence with anything you want.. "I use____ and I've never had a problem"...

Generally when there are 2 variants of the same capacity engine Merc will designate them as ...L and ...LX. I guess it started as a 5.0L (as in 'Litre') with a 2bbl carb, and when the 4bbl was added, the X is for 'extra'.... Who knows, it could all be just another marketing ploy. Much like cars are badged.... JMHO

Chris.......

Click to expand...

Well I use oil and I've never had a problem

Re: Motor oil...OEM Only?

I like oil threads!

Re: Motor oil...OEM Only?

Brand name is not significant.

Use Merc, Shell, Wal-Mart Super-Tech...whatever.

Just make sure you keep it changed every 100 hours or so/end of the season...whichever comes first. Keep an eye on the dipstick for correct level and signs of water intrusion. Use a good filter and if you want to get a snapshot of how your engine is wearing/how your oil is performing...send it to a lab to be tested. Cheap test and will allow a "peek" into the inner workings/potential problems(gas/oil/water/coolant intrusion) within a specific powerplant.

Oil threads are a dime-a-dozen here...or virtually any powersport forum.

Re: Motor oil...OEM Only?

HT32BSX115 said:

I like oil threads!

Click to expand...

We know you do , and you're good at them.

Since the engine in question engine is not emission controlled with a catalysts system the manufacturers recommended oil specific specification is not as critical for you're engine vs the newer catalysts system.

If you decide to not run the manufacturers recommended engine oil brand & weight, then you are in the clear to run just about any good quality name brand oil & weight you choose that is on the shelf.

Try to pick your oil weight to average the ambient air temp you would run in if possible.

My personal recommendation would be to pick one and stick with it.

Here's a hint, new engines from GM are said to come with straight 30 weight oil.

If Mercury MerCruiser Full‑Synthetic, 20W‑40 oil is unavailable, use the following lubricants, listed in order of recommendation. If you are servicing a catalyst engine, use these for short periods of time only.
1. Mercury/Quicksilver 25W‑40 Synthetic Blend, NMMA FC‑W–rated 4‑cycle MerCruiser oil.
2. Mercury/Quicksilver 25W‑40, NMMA FC‑W–rated 4‑cycle MerCruiser oil.
3. Other recognized brands of NMMA FC‑W–rated 4‑cycle oils.
4. A good‑grade, straight‑weight detergent automotive oil according to the last row of the operating chart below.
NOTE: We do not recommend non‑detergent oils, multi‑viscosity oils (other than as specified), non FC‑W–rated synthetic oils, low‑quality oils, or oils that contain solid additives.
SAE 30 W, (32? F) - (50? F)
SAE 40 W, (50? + F)

In the end, armed with this information above, it is your choice.

Hope this helps, good luck.

Re: Motor oil...OEM Only?

Thanks Guys for your input...although i do have a mech.Elec. background....i am a rookie when it comed to marine engines and salt water. So any information provided is very helpfull comming from the guys who know.

Thanks again
Jules

Fun Times said:

We know you do , and you're good at them.

Since the engine in question engine is not emission controlled with a catalysts system the manufacturers recommended oil specific specification is not as critical for you're engine vs the newer catalysts system.

If you decide to not run the manufacturers recommended engine oil brand & weight, then you are in the clear to run just about any good quality name brand oil & weight you choose that is on the shelf.

Try to pick your oil weight to average the ambient air temp you would run in if possible.

My personal recommendation would be to pick one and stick with it.

Here's a hint, new engines from GM are said to come with straight 30 weight oil.

If Mercury MerCruiser Full‑Synthetic, 20W‑40 oil is unavailable, use the following lubricants, listed in order of recommendation. If you are servicing a catalyst engine, use these for short periods of time only.
1. Mercury/Quicksilver 25W‑40 Synthetic Blend, NMMA FC‑W?rated 4‑cycle MerCruiser oil.
2. Mercury/Quicksilver 25W‑40, NMMA FC‑W?rated 4‑cycle MerCruiser oil.
3. Other recognized brands of NMMA FC‑W?rated 4‑cycle oils.
4. A good‑grade, straight‑weight detergent automotive oil according to the last row of the operating chart below.
NOTE: We do not recommend non‑detergent oils, multi‑viscosity oils (other than as specified), non FC‑W?rated synthetic oils, low‑quality oils, or oils that contain solid additives.
SAE 30 W, (32? F) - (50? F)
SAE 40 W, (50? + F)

In the end, armed with this information above, it is your choice.

Hope this helps, good luck.

Click to expand...