Regular Gas in 2 stroke engine?

[swick]

What happens if someone used regular gas in a 2 stroke engine and how long would it take? Are there signs and symptoms to look for? Would there be perminant damage?

 

[Zeeter]

Re: Regular Gas in 2 stroke engine?

Bad. Hard to tell. Noises.

 

[marlboro180]

Re: Regular Gas in 2 stroke engine?

Just think about dropping the oil out of the crankcase of your car and running it down the road. Will it last? Not long. Would it survive? Maybe, but not without some very premature wear on every internal part of the motor. The good thing about a 2 stroke is there is no valvetrain to damage. SO one would just have to deal with scorched / scarred cylinder walls, broken rings , worn out bearings, frozen wrist pins and the like.
If it was run for just a minute , probably not that bad. If for more than that, time for a teardown.

 

[5150abf]

Re: Regular Gas in 2 stroke engine?

Do a compression check to see where you are at, if you hurt it real bad compression will be low or way different.

You are looking for 90+ and within 10% on all cylinders.

 

[JB]

Re: Regular Gas in 2 stroke engine?

"Regular" is the correct gas option for outboards.

Are you talking about the grade of the gasoline or using gasoline without oil in it??

 

[Moody Blue]

Re: Regular Gas in 2 stroke engine?

I think the proper term would be "straight" gas vs mixed gas.

 

[ondarvr]

Re: Regular Gas in 2 stroke engine?

My son did it on his bike, it lasted another month or so before the crank bearings came apart.

 

[a70eliminator]

Re: Regular Gas in 2 stroke engine?

We (did in) a Toro snowblower at work one day (long story) anyhow, we put regular no premix gas in it accidently on purpose LOL, it took only about 2 mins. and it was DONE COOKED SEIZED

 

[swick]

Re: Regular Gas in 2 stroke engine?

I haven't done this, don't think it happened, but someone told me to be careful about buying a used 2 stroke. If everyone here is correct (in saying that the engine would be trashed) it would probably be acting pretty bad, if at all right?

So if it ran for about a minute or so that would have been a minute too long?

Most likely something not to worry about then. Compression test should tell of any probs right?

 

[Frank Acampora]

Re: Regular Gas in 2 stroke engine?

I believe it was OMC who posted a notice that there is usually enough residual oil in a broken-in engine that it could be run at or below 2000 rpm for a good while without doing damage. ME? I wouldn't try it.

Remember: These engines for the vast majority have fully hardened roller bearings at all rotational points. These bearings require very minimal lubrication. Same thing with rings. Once the engine is broken in and piston rings are "seated" they require minimal lubrication. Think about an auto engine with oil control rings. If the sealing rings were actually riding on a film of oil, it would burn off during combustion and the engine would use a lot of oil. Fuel does have SOME lubricating properties which in the case of piston rings apparently is enough. Not enough of an argument? What lubricates and cools the electric fuel pump inside your auto's gas tank? --Not the motor which is sealed, but the positive displacement pump head.

Since these outboards are used on the water and are frequently stored for periods of time on the water, 50-1 ratio oil is a compromise to ensure enough oil in the engine to prevent corrosion damage from moisture infiltration due to humidity when not running. Again, would I try less oil? in a word, NO!

 

[swick]

Re: Regular Gas in 2 stroke engine?

so then what ondarvr and a70eliminator said would not be applicable or realistic with this engine? To be honest I bought my dad a leaf blower long ago, he eventually gave it back to me and I didn't realize it was a two stroke. I had used that thing 1000 time before I realized it. No problems whatsoever. Actually I realized it was a two stroke when I bought a two stoke weed wacker and was mixing the fuel. At that point I through some oil into the gas chamber on the blower and never had a problem with it. Didn't know how severe it could be on an outboard motor or not though.

 

[sschefer]

Re: Regular Gas in 2 stroke engine?

I haven't done this, don't think it happened, but someone told me to be careful about buying a used 2 stroke. If everyone here is correct (in saying that the engine would be trashed) it would probably be acting pretty bad, if at all right?

So if it ran for about a minute or so that would have been a minute too long?

Most likely something not to worry about then. Compression test should tell of any probs right?

Secondary, cylinder compression checks, will tell you a lot about the condition of the pistons and rings. Theres also what's called a primary compression test that you do on the crankcase. If those are within specs according to the manuals and it runs then you're probably good to go. However, lower units are not cheap so make sure it at least goes in and out of gear while running and is quiet. Have the seller pull the drain plug on the L/U and look at lube for signs of water and the plug magnet for signs of metal. Some minor metalic accumulation is normal, chunks are not.

 

[ondarvr]

Re: Regular Gas in 2 stroke engine?

so then what ondarvr and a70eliminator said would not be applicable or realistic with this engine? To be honest I bought my dad a leaf blower long ago, he eventually gave it back to me and I didn't realize it was a two stroke. I had used that thing 1000 time before I realized it. No problems whatsoever. Actually I realized it was a two stroke when I bought a two stoke weed wacker and was mixing the fuel. At that point I through some oil into the gas chamber on the blower and never had a problem with it. Didn't know how severe it could be on an outboard motor or not though.

Any 2 stroke will be damaged if run without oil, just depends on how long and hard it was run as to when it may fail. I had a friend let me use a ratty old 2 stroke bike he had so we could ride up a long trail (bad road) to start our hike. He always had 4 stroke bikes before this one and knew nothing about mixing gas. It wasn't until a couple months after the trip that we were talking and he said it was straight gas in the bike when I use it. It most likely did some damage, but it was an old worn out junker and at least ran long enough to me back to the truck.

My son ran his bike for at least an hour on straight gas, or at least a very lean mix because there wasn't much fuel in the tank when he filled it with the non mixed gas. It ran for another month before it self destructed.

 

[Home Cookin']

Re: Regular Gas in 2 stroke engine?

I read that Yamahas can run all day without oil at <2000 rpm. Thus you could return to port with a broken pump or empty oil tank. Not that I'd try it but I also wouldn't panic if I knew a motor was run a short while, low speed, on straight gas--such as a start--oh shoot!--shut off escapade. If you think about it, at 50:1 in a small mist of fuel from a jet, that's not a lot of lube. Much less than the oil bath in a V-8 car motor.

But if you are buying one and are concerned it may have been run "straight" then check compression as suggested (engine warm of course) but also run it at high rpm when hot and listen for bad noises/vibes indicating warped or distended metal parts from overheat.

 

[pmat1]

Re: Regular Gas in 2 stroke engine?

years ago i had a 2 stroke 24cc gas scooter, the clutch was dieing, so i started running straight gas through it. the clutch died a month later and the engine kept going. i had to try to kill the motor.

 

[fugi guy]

Re: Regular Gas in 2 stroke engine?

2-stroke engines will run quit some time with out oil if the engine load and rpm are kept low..2000 rpm or less.. The gas entering the crank case through the carbs is enuf lub for the engine bearings, snowmoblie manufactures have done this for years. Stopping the oil flow at idle , many for emissions...The better the octane the slower the burn, the less heat you will have also..my 2 cents.. Bob