Why Oil Injection?

[zonaman]

Once upon a time we added oil to our gas tanks for 2 stroke engines. Somewhere along the line they went to oil injection. Seems like a lot of extra parts and complication. There must be some benefits over the simplicity of mixing oil in the tank . What's the story on this?

Thanks

 

[airshot]

With oil injected motors, the oil use is much less for the enviorment. Injected motors use a 100 to 1 ratio at idle, less smoke and smell then go up to a 50 to 1 or richer for high speed running. All about getting two stroke emisions lowered. I have recently moved into an oil injection motor. My previous oil injected motors had there issues ( all omc models). Currently bought a Mercury injected, talked to numerous mechanics and did a bunch of research !!! My recent buy us in mint condition, one owner, properly maintained, so I feel comfortable with it. Like anything maintenence is everything !!

 

[jimmbo]

Years ago, when we did add the Oil into the Gas, it wasn't always done properly or with the correct amount. Some people had trouble with the Math, others would carefully measure out the Correct amount of Oil, fill the Tank with Gas, then pour the Oil in, put the Cap on the tank and start the Engine. No stirring/mixing, and oil being Heavier than Gasoline would settle on the Bottom of the tank. That would result in a Very Large amount of Oil at the Beginning, and almost no Oil as the Tank was close to Empty. It was also a Pain to mix add Oil to Built in Tanks, unless you were to mix it in 6 gallon Pails, then pour it in the Tank.
So the Engine Makers, tired of seeing their Product being mistreated, and often suffering a Horrible Twitching Death, developed Oil premixing Systems, as Oil wasn't actually Injected into the Engine. Of course, even though the Systems were quite well Engineered, some owners managed to go out of their way to undermine them.

 

[racerone]

We live in a time of CONVENIENCE.-----People want / demand convenience in this day and age.-----Factories build / sell what people take out of the show rooms.------Outboards are now very complex and many folks will find out that convenience cost big $$$$.----Some use mixing systems.----Some inject the oil without mixing( Yamaha and E-tec , Optimax ETC ) --Shops now cost $150 / hr ( tax included ) to repair this stuff.-----EV cars will be another story in years to come.------Throw it away stuff.

 

[Scott Danforth]

Once upon a time we added oil to our gas tanks for 2 stroke engines. Somewhere along the line they went to oil injection. Seems like a lot of extra parts and complication. There must be some benefits over the simplicity of mixing oil in the tank . What's the story on this?

Thanks

will expand upon all the other reasons above

once upon a time, SAE 30 was the oil that was mixed with gasoline for 2-cycle motors. high ash content and expanded use meant that the exhaust fumes needed to be cleaned up. the oil slowly evolved to todays synthetic

the poor mixing practices of the user of yore meant that if too much oil was used, the exhaust emissions was more harmful, there was more smoke and the exhaust would drip oil sludge and the plugs would foul and the general population got mad. if too little oil was used, the motor would suffer a lack of oil breakdown and the motor owner would blame the motor manufacturer for the failure vs realizing they are too stupid to do math and add proper oil.

additionally, mopeds, motorcyles, etc. were two stroke, and to properly mix 0.34 gallons of fuel while stopping for gas on a small trip meant you were guaranteed to mix the fuel improperly

so along come a bunch of engine builders that added oil injection to things like automobiles, snowmobiles, motorcycles and mopeds in the late 60s and early 70's. that $5 extra in parts meant proper oiling if you put in 0.1 gallons of fuel or 100 gallons of fuel.

testing showed that at idle, 100:1 or 75:1 or 200:1 was all that was needed to keep the motor happy and not have sludge build-up in the exhaust. This meant the newer 2-strokes could be more emission friendly with proper oil ratio for the loading at hand

so now these same boat owners that own 2-stroke motors that have oil injection want it on their boat motors and beg and plead....

now any 2-stroke (except small engines) has a little oil injection pump. the user is happy, the emissions folks are happy, the motor is happy.

weed whackers and chain saws and other small engines are filled from a 1 gallon or 2 gallon can, so those engines have better control on the oil mix ratio and are slowly becoming less prevelant, so there is no benefit from auto-mixing and these motors are in a price-competitive market, where $2 buys brand loyalty.

 

[zonaman]

So emissions, convenience, and less oil fouling seem to be the motivations. I seem to have run into more than a few people who, frustrated by finicky alarms and a desire for simple foolproof ( provided you can read side of a 2 stroke mix bottle) systems, remove/bypass the oil I injection equipment.

 

[Scott Danforth]

So emissions, convenience, and less oil fouling seem to be the motivations. I seem to have run into more than a few people who, frustrated by finicky alarms and a desire for simple foolproof ( provided you can read side of a 2 stroke mix bottle) systems.

These same people haven't maintained their motor per the manual.

 

[racerone]

People invent new ways to destroy 2 stroke motors every day.------The concept of 2 strokes / mixing gas and oil / lubrication is not well understood by some.

 

[dingbat]

simple foolproof (provided you can read side of a 2 stroke mix bottle) systems

I'm all ears if someone can come up with a "simpler, fool proof" method of mixing 150 gallons of fuel than filling a dedicated 3 gallon tank full of oil....lol

 

[dwco5051]

I am old enough to remember putting one quart of straight 30 weight into 5 imperial gallons of gas. Back then everybody and one or two extra sets of spark plugs in their tackle boxes. If you did a lot of trolling you would clean the plugs for the next days fishing. Now most plugs that people change probably don't really changed that often.

 

[airshot]

I'm all ears if someone can come up with a "simpler, fool proof" method of mixing 150 gallons of fuel than filling a dedicated 3 gallon tank full of oil....lol

Learn your fuel gage reading, depending on what you gagevreads, say you estimate it will take 75 gallons to fill it up....add enough oil for 50 gallons then fill with 50 gallons of fuel. So what if you tank is not perfectly full ?
Each time you add fuel you will soon learn how accurate your gage is and will add the correct amount of oil...remember your tank does not have to be perfectly full as long as your oil ratio is correct for the amount of fuel you add. Did that for many years with no issues!!

 

[QBhoy]

will expand upon all the other reasons above

once upon a time, SAE 30 was the oil that was mixed with gasoline for 2-cycle motors. high ash content and expanded use meant that the exhaust fumes needed to be cleaned up. the oil slowly evolved to todays synthetic

the poor mixing practices of the user of yore meant that if too much oil was used, the exhaust emissions was more harmful, there was more smoke and the exhaust would drip oil sludge and the plugs would foul and the general population got mad. if too little oil was used, the motor would suffer a lack of oil breakdown and the motor owner would blame the motor manufacturer for the failure vs realizing they are too stupid to do math and add proper oil.

additionally, mopeds, motorcyles, etc. were two stroke, and to properly mix 0.34 gallons of fuel while stopping for gas on a small trip meant you were guaranteed to mix the fuel improperly

so along come a bunch of engine builders that added oil injection to things like automobiles, snowmobiles, motorcycles and mopeds in the late 60s and early 70's. that $5 extra in parts meant proper oiling if you put in 0.1 gallons of fuel or 100 gallons of fuel.

testing showed that at idle, 100:1 or 75:1 or 200:1 was all that was needed to keep the motor happy and not have sludge build-up in the exhaust. This meant the newer 2-strokes could be more emission friendly with proper oil ratio for the loading at hand

so now these same boat owners that own 2-stroke motors that have oil injection want it on their boat motors and beg and plead....

now any 2-stroke (except small engines) has a little oil injection pump. the user is happy, the emissions folks are happy, the motor is happy.

weed whackers and chain saws and other small engines are filled from a 1 gallon or 2 gallon can, so those engines have better control on the oil mix ratio and are slowly becoming less prevelant, so there is no benefit from auto-mixing and these motors are in a price-competitive market, where $2 buys brand loyalty.

I had no idea that 30 weight was once used for 2 strokes. Always learning on here.

 

[racerone]

The times and products gave changed.----It is what was available at the time.----Heck my dad remembered when folks talked about a new radio.-----Some said that you would be able to see people talk on a radio.

 

[QBhoy]

Should probably add, that oil injection (autolube, vro and similar) set ups are very different from the more recent di engine set ups. The former, you could do away with the oil injection and pre mix. The latter, you can’t (as far as I am aware), due to the way the oil is distributed
Upside of the latter is that oil consumption may be a little lessened and emissions are lower. Downside…I have never trusted such a thing…

 

[racerone]

Correct----On direct injection motors only the gasoline is injected into the cylinder after ports are closed.-----Oil is totally seperate and inhectted where needed.-----It can be said that these motors are in 4 stroke mode for part of the crank rotation.

 

[jimmbo]

Correct----On direct injection motors only the gasoline is injected into the cylinder after ports are closed.-----Oil is totally seperate and inhectted where needed.-----It can be said that these motors are in 4 stroke mode for part of the crank rotation.

Actually, one of the DI designs, I cant' remember if it was FICHT, or Optimax, did add a very small amount of Oil to the Fuel, about 0.2(500:1) - 0.25(400:1)%. The Rationale was that the Oil would lubricate the Injector, and the Detergent in it, would keep the Injector cleaner.

 

[racerone]

Correct ----That insignificant amount of oil on ficht had nothing to do with operation of a 2 stroke engine.

 

[QBhoy]

Actually, one of the DI designs, I cant' remember if it was FICHT, or Optimax, did add a very small amount of Oil to the Fuel, about 0.2(500:1) - 0.25(400:1)%. The Rationale was that the Oil would lubricate the Injector, and the Detergent in it, would keep the Injector cleaner.

You’re spot on jimmbo. As far as I can remember, the seadoo di 951 I was cursed with owning years ago, had a system that put some oil to the throttle bodies…and or injectors…as well as obviously directly supplying oil to other distribution lines to specific areas around the engine.

 

[airshot]

I had no idea that 30 weight was once used for 2 strokes. Always learning on here.

Hate to admit it but can remember using a can opener, the type with the pointed end that punched a triangle hole into the lid of a quart oil can of straight 30 wt oil for my old outboard motor of a whopping 5 hp. Added that whole quart to a six gallon fuel tank. You added a gallon or two of gas then sloshed it around to get it to mix then added some more gas to slosh it around some more!! Getting it thoroughly mixed was a real effort, todays oil mixes quite easily, back then it was a real chore...however the only real advantage back then, was the mosquitoes stayed away as long as your outboard was running!!!!!

 

[QBhoy]

Hate to admit it but can remember using a can opener, the type with the pointed end that punched a triangle hole into the lid of a quart oil can of straight 30 wt oil for my old outboard motor of a whopping 5 hp. Added that whole quart to a six gallon fuel tank. You added a gallon or two of gas then sloshed it around to get it to mix then added some more gas to slosh it around some more!! Getting it thoroughly mixed was a real effort, todays oil mixes quite easily, back then it was a real chore...however the only real advantage back then, was the mosquitoes stayed away as long as your outboard was running!!!!!

Love reading and hearing such things ! Brilliant. Guys like yourself should make certain that they scribe/write down, or at least verbally pass on things like this. Things like this will soon be gone from living memory.
I’m middle aged myself, but was lucky enough to remember my father having a lovely old wooden boat as a boy. She had a kelvin petrol engine in her. To start this engine, it required my dad to use a syringe of fuel (or possibly paraffin) into a port, manually advance the timing and then hand crank her over with the starting handle. She had beautiful brass wheels at the helm..one for steering via chain drive and the other for gear selection. Sadly, the latter and pictured below, is all that remains of her. She’d be over a century old by now at least.