Synthetic oil?

[Kermit]

I have a 2000 6hp 2-stroke Johnson. The previous owner kept in in saltwater and never flushed it with fresh water after using it. It's not pretty but runs very well. Starts on the 3rd pull and sometimes even on the 2nd. Then cranks on the first pull even after 2 hours or more of sailing. I disconnect the fuel line while it's running to let the fuel run out before buttoning up for the day.

A buddy of mine says I should be using synthetic oil. He says it will run without smoking and last alot longer than with normal oil. (The smoke was not an issue with me until he commented on it.) A mechanic at a nearby marina says synthetic oil in my engine is not necessary and will do very little extra good over normal oil. After doing my own research I found that once I use synthetic oil I can never go back to regular oil. Something to do with molecules.

I was all ready to switch to synthetic until the mechanic said what he did. The never-go-back issue has me a little skeptical, too. I've always been an "If it ain't broke don't fix it" kinda-guy. I've also learned that if I go against my gut feeling, I seem to always regret it. My gut feeling is that it ain't broke and there's no need to fix it. My buddy can't understand why the mechanic said what he did and is insisting I switch to synthetic.

I'd love feedback on oils. Any thoughts would be greatly appreciated. I sail on an inland lake in South Carolina. The weather here is considered mild even in the winter. We do get hard freezes but they are not particularly common. We have very hot humid summers and beautiful springs and falls.

Thanks!

 

[Benny]

I heard something about 2 stroke synthetic oils creating increased deposits in the exaust port area. I would stick with the engine manufacturer recommendations.

 

[XPatriot]

I have a 2000 6hp 2-stroke Johnson. The previous owner kept in in saltwater and never flushed it with fresh water after using it. It's not pretty but runs very well. Starts on the 3rd pull and sometimes even on the 2nd. Then cranks on the first pull even after 2 hours or more of sailing. I disconnect the fuel line while it's running to let the fuel run out before buttoning up for the day.

A buddy of mine says I should be using synthetic oil. He says it will run without smoking and last alot longer than with normal oil. (The smoke was not an issue with me until he commented on it.) A mechanic at a nearby marina says synthetic oil in my engine is not necessary and will do very little extra good over normal oil. After doing my own research I found that once I use synthetic oil I can never go back to regular oil. Something to do with molecules.

I was all ready to switch to synthetic until the mechanic said what he did. The never-go-back issue has me a little skeptical, too. I've always been an "If it ain't broke don't fix it" kinda-guy. I've also learned that if I go against my gut feeling, I seem to always regret it. My gut feeling is that it ain't broke and there's no need to fix it. My buddy can't understand why the mechanic said what he did and is insisting I switch to synthetic.

I'd love feedback on oils. Any thoughts would be greatly appreciated. I sail on an inland lake in South Carolina. The weather here is considered mild even in the winter. We do get hard freezes but they are not particularly common. We have very hot humid summers and beautiful springs and falls.

Thanks!

Use any 'what brand is on sale' dyno oill of the weight recomended and change it once a season.

Unless you motor up and down the lake for hours at a time, several days a week, the dyno oil will more than last for a season's use- putting synthetic in it will just be pouring money away.

2-smokes do exactly that....smoke. Changing the oil isn't going to make it start any easier or smoke any less.

If you want to read more on the subject, Google synthetic v dyno oil and you'll be able to waste the next 6 months reading opposing views on the subject and be no more certain one way or the other.

Good Luck!

 

[kloudie1]

Read this from Sea Doo.. a pretty good article about two stroke oils..
http://www.sea-doo.net/techarticles/oil/oil.htm

 

[Alan]

XPatriot, 2 stroke engines do not get oil changes, their oil is mixed with the fuel either directly in the fuel tank or by oil injection in the crankcase. It is then burned with the fuel. My 2 stroke Yamaha uses full synthetic Yamalube at a 100:1 ratio. If some other oil is used Yamaha suggests a 50:1 ratio. Regardless of whether or not you can see any smoke the higher the ratio the less oil is being burned and dumped into the water.

 

[Bill Roosa]

from an old 2-cycle motorcycle manic

The use of synthetic is not recommended by the larger mills. While it does burn clean is has one really bad property that makes it a non starter in my mind. It does not have very good extreme pressure properties.
As a reference STP oil treatment has EXTREME extreme pressure properties. Dip the end of a screwdriver in it and you CANNOT hold the thing between your fingers! It totally separates you from the metal and provides a liquid barrier between your fingers and the metal. Kerosine has VERY poor estreme pressure properties. It is like anti-oil which is why it cleans so well.
Your bearings and rings absolutly need extreem pressure protection and the natrual oils provide better service even if they do smoke a little more.

 

[rb437]

Alan is correct about mixing the oil and gas so I wonder, is running it out of gas a good idea?

 

[Brian M H23]

Synthetic oil has bad EP lubrication? When did this happen? Ever seen a car engine run for 200k miles on synthetic? It looks brand new inside!

BTW, there is very little pressure between the rings and the cylinder wall, it's a "Scraping" action. An engine with high cylinder wall pressures is often called, by the layman, "siezed"

 

[Kermit]

Thanks for all your input. After reading everyone's opinions (and as much of the technical explanation I could absorb), I've decided that there's no correct answer. Unless, of course, the previous owner used synthetic oil. Then I have no choice but to use synthetic.

So my final answer is that my motor ain't broke so I ain't gonna fix it. The only truly compelling reason for switching (that I can really think of) is to keep my buddy from shaking his head and telling me I'm crazy for not switching. I've realized it's my boat and I'm comfortable using regular 50:1 outboard motor oil. Maybe one day I'll decide to switch. But for now the motor runs great and I have no mechanical reason for switching.

Thanks to everyone for replying.

 

[Clark]

Just use a high quality, low ash 2-stroke oil and some stabilizer good for gasoline/ethanol.