Oil mix ratio.

[OM617YOTA]

I've run 16:1 without any issue. Normal mix was 32:1, but MX2T had no dye at all, and Mobil Racing 2T has a very light red color, which doesn't help at all when the fuel is in a red gas can. Wasn't sure if I had mixed it, so added another dose. Once it started running, I could tell by the smell that I'd double dosed. Oh well, 16:1 is a whole lot better than 128:0. No issues.

I think spark plug fouling is largely eliminated with modern synthetic oils.

 

[Pioneer]

I think the ratio should match the power output vs displacement. Golf cart engines must be really under stressed.

 

[Chevboy0167]

Well, I will say this auger runs great with a hint of smoke mixed at 32:1 instead of 24:1. Actually it runs great for a fixed jet! Back home to the owner it goes.

 

[Ted Jenkins]

I've run 16:1 without any issue. Normal mix was 32:1, but MX2T had no dye at all, and Mobil Racing 2T has a very light red color, which doesn't help at all when the fuel is in a red gas can. Wasn't sure if I had mixed it, so added another dose. Once it started running, I could tell by the smell that I'd double dosed. Oh well, 16:1 is a whole lot better than 128:0. No issues.

I think spark plug fouling is largely eliminated with modern synthetic oils.

The biggest problem with too much oil is burning up the engine because mixture is too lean. As long as the carb is running rich enough to allow for extra oil then no worries. open High needle a touch and turn it in next time. Thanks

 

[Ted Jenkins]

I've run 16:1 without any issue. Normal mix was 32:1, but MX2T had no dye at all, and Mobil Racing 2T has a very light red color, which doesn't help at all when the fuel is in a red gas can. Wasn't sure if I had mixed it, so added another dose. Once it started running, I could tell by the smell that I'd double dosed. Oh well, 16:1 is a whole lot better than 128:0. No issues.

I think spark plug fouling is largely eliminated with modern synthetic oils.

The biggest problem with too much oil is burning up the engine because mixture is too lean. As long as the carb is running rich enough to allow for extra oil then no worries. open High needle a touch and turn it in next time. Thanks

 

[OM617YOTA]

The biggest problem with too much oil is burning up the engine because mixture is too lean. As long as the carb is running rich enough to allow for extra oil then no worries. open High needle a touch and turn it in next time. Thanks

I don't buy the more oil = less fuel argument anymore. Back in the days of castor oils, where you'd have schmoo running out the muffler, no the oil isn't burning, just making a mess. Modern oils, the oil burns and contributes to the BTU content of the mix, and doesn't fill your muffler with schmoo. Like any saw, tune for what you're running.

Always tune for what you're running.

 

[KASH]

From what you say
If too much oil leans out the mixture and causes the engine to seize then anyone with a fixed jet carb is pretty well assured if they put in to much oil their motor is history.
Kash

 

[Ted Jenkins]

From what you say
If too much oil leans out the mixture and causes the engine to seize then anyone with a fixed jet carb is pretty well assured if they put in to much oil their motor is history.
Kash

There is some truth to that. However Auto tune systems are designed to work in certain parameters as the same issues would be true if you ran a mix of 200:1 oil ratio. As OM has suggested that each fuel load needs to be tuned for. If an OP runs a consistent 34:1 then tuning will not likely ever be an issue other than an occasional check over. Or add too much oil displaces too much fuel or too little oil will cause other issues. Thanks

 

[Slotracer577]

Oil migration is really what determines how much oil is needed. Usually the smaller, thus higher rpm the more oil an engine needs. Also more hp, more oil. Low hp and low rpm can get away with less oil. a good article https://motocrosshideout.com/2-stroke-dirt-bike-pre-mix-101/

 

[tomalophicon]

Oil migration is really what determines how much oil is needed. Usually the smaller, thus higher rpm the more oil an engine needs. Also more hp, more oil. Low hp and low rpm can get away with less oil. a good article https://motocrosshideout.com/2-stroke-dirt-bike-pre-mix-101/

So by the logic outlined in that article we should be using around 18:1.

 

[Slotracer577]

So by the logic outlined in that article we should be using around 18:1.

Not sure it’s that rich, but probably richer than 32:1. One thing, saws are pretty low power per CC compared to motorcycles. An kx80 probably makes 15-18 hp. A long way from the 6 my 7900 makes.

 

[tomalophicon]

Not sure it’s that rich, but probably richer than 32:1. One thing, saws are pretty low power per CC compared to motorcycles. An kx80 probably makes 15-18 hp. A long way from the 6 my 7900 makes.

OK I wasn't sure how powerful they were compared to motorcycles of equivalent displacement.
And I was thinking that with all the full throttle application they are run pretty hard, but in reality most saws will go short bursts of full throttle with a fair bit of idling or even being shut down in between.
Cheers
Tom.

 

[Ted Jenkins]

You are very correct in saying that most two smoke dirt bike engines out perform most every thing else. That would be in terms of torque and combined HP. Chain saw engines configuration is very different in terms of porting. MX motors are designed around the expansion chamber which very much enables them to produce mega HP. For those who do milling with a chainsaw put the tune and cooling on the line because they run very hard for several minutes non stop. When I was racing in Grand Prix's I would run often twenty minutes full throttle with only a minor variation then back on the throttle for another twenty minutes and yes I set up motors for a specific use or application. So in either case jetting and tuning very much matter. Thanks

 

[huskyespañol]

La motocicleta esta refrigerada por agua

 

[Wow]

Oil thread!

Well like the old farmer said,,Everytime we get a new hand we have to explain how the Hay bailer works..Every group I've been on the new guys and some of the old guys like picking up old threads and at times old ladies..So,,lets do this,,I'm 74 so OLD habits are hard to break..Four ounces of oil to a gallon was my opinion for years then finally 3.2 ounces per gal and then 3 ounces per gallon..I change slowly..then,,I started looking at CC's..I am from the school the bigger engines like more oil.. Since some of my stuff requires 3.2 ounces I keep life simple and that's now my standard...32 to 1 is not a big deal for me BECAUSE,,once the saw is adjusted to burn that oil it's not messing up my plugs and it's simple..As an old timer I'd recommend 4 ounces or 3.2 ounces per gallon BECAUSE,, many gas pumps that I've tested are seldom exactly set right on the money. I have a gallon jug with a mark on it.. I've tested different pumps some side by side and got different readings..If a saw is tuned right and GOOD 2 cycle oil is used every bit of that oil will burn along with the gas and the saw has no idea how it was mixed..HOWEVER if you starve the engine JUST ONCE, that saw may have along memory..The rule I go by is FEED the saw plenty of oil..Never pizz off anything with an engine..They KNOW exactly when to get you back..So if you are new to this saw stuff..I recommend you use 3.2 ounces or 4 and adjust the carb..You will be blowing out Birthday candles for that saw for years to come IF you bought a good saw to start with..For a farm I've fell in love with Echo saws..From the cs352 and up..I use that little saw and the cs490 more than I use my big heavy Sthil saws which require Sthil bars...what I love about the Echo cs352 other than it starts easy and runs so well, it's a 3/8 pitch and they can use the cheap Poulan chain and bar combos..I catch them on sale sometimes..Paid 15 bucks for a new bar and chain just recently..Throw in a jar of Peanut butter, Jelly and loaf of bread and "that's" a sweet deal..

Oil thread!

 

[Ted Jenkins]

Well like the old farmer said,,Everytime we get a new hand we have to explain how the Hay bailer works..Every group I've been on the new guys and some of the old guys like picking up old threads and at times old ladies..So,,lets do this,,I'm 74 so OLD habits are hard to break..Four ounces of oil to a gallon was my opinion for years then finally 3.2 ounces per gal and then 3 ounces per gallon..I change slowly..then,,I started looking at CC's..I am from the school the bigger engines like more oil.. Since some of my stuff requires 3.2 ounces I keep life simple and that's now my standard...32 to 1 is not a big deal for me BECAUSE,,once the saw is adjusted to burn that oil it's not messing up my plugs and it's simple..As an old timer I'd recommend 4 ounces or 3.2 ounces per gallon BECAUSE,, many gas pumps that I've tested are seldom exactly set right on the money. I have a gallon jug with a mark on it.. I've tested different pumps some side by side and got different readings..If a saw is tuned right and GOOD 2 cycle oil is used every bit of that oil will burn along with the gas and the saw has no idea how it was mixed..HOWEVER if you starve the engine JUST ONCE, that saw may have along memory..The rule I go by is FEED the saw plenty of oil..Never pizz off anything with an engine..They KNOW exactly when to get you back..So if you are new to this saw stuff..I recommend you use 3.2 ounces or 4 and adjust the carb..You will be blowing out Birthday candles for that saw for years to come IF you bought a good saw to start with..For a farm I've fell in love with Echo saws..From the cs352 and up..I use that little saw and the cs490 more than I use my big heavy Sthil saws which require Sthil bars...what I love about the Echo cs352 other than it starts easy and runs so well, it's a 3/8 pitch and they can use the cheap Poulan chain and bar combos..I catch them on sale sometimes..Paid 15 bucks for a new bar and chain just recently..Throw in a jar of Peanut butter, Jelly and loaf of bread and "that's" a sweet deal..

Wow a little long winded but I like it. Some facts to deal with. Not all oil is created the same as well is not all fuel is the same either. Rule of thumb the ratio of oil mix will depend on the oil itself and yes the fuel matters too just not as much but still matters. I just went through a couple of gallons of Yamalube and I liked it but I ended up with a ratio almost 40:1. When I used Maxima I ran a ratio close to 34:1. I believe every mix has a particular sweet spot that is just right. Too much oil will wear out an engine just as fast as too little. I do have several thousand engines that I can draw experience from. There are those who think 100:1 is just right and I do not agree with them but many have ran those engines for many hours with a smile. Thanks

 

[bwalker]

Wow a little long winded but I like it. Some facts to deal with. Not all oil is created the same as well is not all fuel is the same either. Rule of thumb the ratio of oil mix will depend on the oil itself and yes the fuel matters too just not as much but still matters. I just went through a couple of gallons of Yamalube and I liked it but I ended up with a ratio almost 40:1. When I used Maxima I ran a ratio close to 34:1. I believe every mix has a particular sweet spot that is just right. Too much oil will wear out an engine just as fast as too little. I do have several thousand engines that I can draw experience from. There are those who think 100:1 is just right and I do not agree with them but many have ran those engines for many hours with a smile. Thanks

Never seen an engine worn out from too much lubricant.

 

[Ted Jenkins]

Never seen an engine worn out from too much lubricant.

Actually a engine with a rich oil mixture will not even wear out it will just hand grenade. When carbon builds up causing a stuck ring or just plain seize. A little is great how about a lot more. Run a few good oils at 16:1 and get back to me in a year. Thanks

 

[bwalker]

Actually a engine with a rich oil mixture will not even wear out it will just hand grenade. When carbon builds up causing a stuck ring or just plain seize. A little is great how about a lot more. Run a few good oils at 16:1 and get back to me in a year. Thanks

Except that doesn't happen. I've plenty of expiereance running rich ratios. Piston ring grooves are typically cleaner. And why wouldn't they be given as you run more oil you also run my detergents through the motor.

 

[sean donato]

Would be very oil addative dependent for carbon build up and removal. I'd hazard to say most modern oils would be fine at higher ratios, but then again I've never seen the point in small power equipment. They are about as low power as you could ask for, any power sports engines dwarf the hp numbers our saws see.