[TwilightArmy]

I purchased a boat with a 2005 90 hp Merc a couple of weeks ago. The previous owner used conventional oil. Since I purchased the boat I have been running synthetic. I still have a gallon of conventional I keep in the boat as a spare. Is it bad to mix the two? I plan on continuing to use the synthetic but should I replace my "spare" with synthetic as well or would it be ok to mix the two if I need to do so on the water?

 

[Neilslure]

I have always heard to be consistant in which oil you use. I think you would be fine if you used most of the synthetic in your tank and then dumped in the spare gallon, as long as you arent mixing a gallon of one with a gallon of the other. I always run Yamalube in mine but once or twice I have got in a pinch on the water and stuck with whatever the marina had to get me home.

 

[Fish_Fiend]

There is a ton of misconception out there about synthetic versus conventional.

Synthetic Oil of any sort is like distilled water. Conventional oil is like old farm pond water. Which do you want to drink?

Honestly there are a ton of benifits to synthetics except the price.

Ask yourself this...if its bad to mix them why do they sell synthetic blend oils?

Gene - Red》X《 - Asheboro

 

[Lucky Doug]

I agree with NeilsLure that I would not mix them equally but try to run one out before changing, although I have heard not to switch back and forth too.

Fish_Fiend is right bout the benefits to synthetic and I would like to know too, WHY do they sell synthetic blends? Maybe it give the buyer a warm fuzzy feeling.

I was made a believer in synthetics back in the 70's when my old Sea Queen would foul a plug about every time you pulled the cord. Used synthetic and never fouled a plug after that.

Now, I believe the conventional oils are of much higher quality as well as the technology in modern (post 1970) engines. Would not have a problem running them in any engine. "Many benefits to synthetic except the price". Agreed, but I have never kept an engine long enough to realize the benefits of synthetics and, believe me, I run them long and hard.

 

[Girkman]

If we are talking about 2 stroke marine oils its not going to do anything. But, if we are talking about 2 stroke lawn and garden mixed with marine NO! you are looking to hurt your engine. Basically they run the same way but a lot of those synthetic are engine specific and when you set the ECU, ECM or EMM which ever engine you own it can extend life, but if its just to run a basic 2 stroke you will be fine.

 

[sundrop]

I would use up the conventional slowly. A 20-25% mix or so, so as not to change the characteristics of the synthetic oil much. "Some" techs claim that the actual viscosity differs and can cause damage "jerking" the pump drive because the two never truly mix, kind of like going from running in water to running in mud then back to sand then water then mud etc etc..

 

[Fish_Fiend]

Fish_Fiend is right bout the benefits to synthetic and I would like to know too, WHY do they sell synthetic blends? Maybe it give the buyer a warm fuzzy feeling.

Its a price point compromise. You get added benifit od synthetic base stock with the affordability of conventional package addatives. The problem with Synth Blend oils were seing now is there is no regulative authority to say how much Synthetic Base Stock must be used in order to warrant the title of Synthetic Blend. This means a company can put a thimble full of base stock in a 55 gallon drum and it is technically Synthetic Blend. Choose your brands wisely Pennzoil gaurantees at least 30% synthetic base stock in there blends. I still run Pennzoil Ultra in everything I own.



Gene - Red》X《 - Asheboro