What Oil to use in 2005 3.0 TKS Mercruiser & how much?

[welder30]

Hey guys, I just bought a 2005 Bayliner 185 BR with 3.0 Mercruiser and wanting to change the oil before its first startup (was a repo boat) and read on mercruisers sight where they recommend 20w40 full synthetic mercruiser oil and if not to use 25w40 others. I just called 4 different different parts stores to no luck at all! What do you guys use recommend me to do? I really want to take it out tomorrow for a test run. Any imformation would be really appreciated. I spoke with the original owner and was told the boat hasnt been ran in a couple of yrs & recommended my changing it also. Thanks again, Tony

 

[Oshkosh1]

Re: What Oil to use in 2005 3.0 TKS Mercruiser & how much?

Put some straight 30W in it (Shell Rotella T/Mobil Delvac) and take it out. If you're feeling guilty after the test run and when you can find the overpriced Merc stuff...change it. You'll be the only one who knows the difference...your engine certainally won't.

 

[welder30]

Re: What Oil to use in 2005 3.0 TKS Mercruiser & how much?

Put some straight 30W in it (Shell Rotella T/Mobil Delvac) and take it out. If you're feeling guilty after the test run and when you can find the overpriced Merc stuff...change it. You'll be the only one who knows the difference...your engine certainally won't.

So, it wont hurt the engine to do that? I read something about the catalist system may be damaged useing other oils but I know half one hears is so we will buy the high dollar oil LOL Thank you for the reply sir. Tony

 

[Oshkosh1]

Re: What Oil to use in 2005 3.0 TKS Mercruiser & how much?

So, it wont hurt the engine to do that?

No...
Unless you're planning on alot of cold(below 40)starts...it's fine. I know several people(myself included) who use it. I found the Shell RotellaT on sale for $12 a gallon, so I bought 5 jugs of it. Should last me the next 4 oil changes.

 

[JimS123]

Re: What Oil to use in 2005 3.0 TKS Mercruiser & how much?

Since you didn't pay much for the used boat and don't plan on keeping it very long, just buy the cheapest thing you can find. Personally, I bought mine brand new and paid a lot for it and I plan on keeping it almost forever so very simply I use what the owner's manual says. I'm blessed in that my local Mercruiser dealer discounts everything so the premium price I pay for an oil change is a mere 20 bucks. For a one year event the 20 bucks doesn't bother me in the slightest.

 

[Oshkosh1]

Re: What Oil to use in 2005 3.0 TKS Mercruiser & how much?

Since you didn't pay much for the used boat and don't plan on keeping it very long, just buy the cheapest thing you can find.

I didn't read where he stated WHAT he paid and how long he wanted to keep it for.

Anyhow...

What he paid, and how long he plans on keeping it is irrelevent. Owners manuals are also trying to sell their products in many cases. Merc doesn't make their own oil...there's better for less.


Brand of oil is nowhere near as important as changing it @50hrs or so and using a good filter. If a lab can't tell brand difference in a UOA(UsedOilAnalysis)...neither can you, OR your engine.

 

[Fishermark]

Re: What Oil to use in 2005 3.0 TKS Mercruiser & how much?

I read something about the catalist system may be damaged useing other oils

Does your engine have a catalytic converter?

Here's what Mercruiser says:

IMPORTANT: Lubrication requirements for catalyzed engines differ from the requirements for non-catalyzed engines. Some marine-grade lubricants contain high levels of phosphorus, which can damage the catalyst system on MerCruiser engines. Although these high-phosphorus lubricants may allow acceptable engine performance, exposure over time will damage the catalyst. Catalysts damaged by lubricants containing high levels of phosphorus may not be covered by the MerCruiser Limited Warranty.
If Mercury MerCruiser Full-Synthetic, 20W-40 oils 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.
Mercury/Quicksilver 25W-40 Synthetic Blend, NMMA FC-W-rated 4-cycle MerCruiser oil
Mercury/Quicksilver 25W-40, NMMA FC-W-rated 4-cycle MerCruiser oil
Other recognized brands of NMMA FC-W-rated 4-cycle oils
A good-grade, straight-weight detergent automotive oil according to the last row of the operating chart below.

 

[Oshkosh1]

Re: What Oil to use in 2005 3.0 TKS Mercruiser & how much?

My point was that in the short term(testing) to use basically whatever you can find in a SAE 30w. Long term...as long as the oil meets the required specification regardless of brand, it'll be safe to use.

Catalyst poisioning in any vehicle is a result of the ZDDP(zinc-blahblahblahphosphate) additive. In the mid 2000's or so, the feds cut the allowable content of ZDDP in oil down to 400PPM(from 1200PPM)specifically because of this issue. ANY standard automotive engine oil sold here since MUST adhere to this new lower level. The exceptions are racing oil, and "extended life" motor oils which may have higher concentrations because of their specific application.

Cat poisoning is not a problem unique to Mercruiser engines. It affects ALL powerplants with catalytic convertors.

Even so, it takes quite sometime to poison your convertor via high phosphorus content oil in an engine which is not suffering from exessive oil consumption. Conversely, you can ruin one in a matter of minutes by running an excessively rich fuel/air mixture because of a leaking injector, bad carb etc...