what does it mean when they say running "too lean" or "too rich&q

[lc]

I'm new to all of this, but I often come across people using these terms. How do you remedy an<br />outboard that is running too rich? Too lean? Thanks for helping out

 

[SpinnerBait_Nut]

Re: what does it mean when they say running "too lean" or "too ri

Re: what does it mean when they say running "too lean" or "too ri

Well, if you are to rich, then it means in a 2 stroke that there is to much oil getting into the cyclinders and if you are to lean, there is not enough and this can be deadly to a 2 stroke. In 4 strokes it means it is not getting enough gas if it is running lean and to much gas if it is rich.<br />Just my .02 worth.

 

[rolmops]

Re: what does it mean when they say running "too lean" or "too ri

Re: what does it mean when they say running "too lean" or "too ri

Hello.<br />When people mention "too rich "or "too lean" they usually mean the mixture of fuel and air that is made by your carburator.<br />"Too rich" means that there is too much fuel in your mixture."To lean" means that there is not enough fuel.<br />You can adjust your mixture with the valve needles on your carburators.<br />By screwing them clock-wise you decrease the amount of fuel and make your mixture leaner and counter clock-wise does the opposite.<br />Now what is the ideal mixture? <br />The one that gives you the highest rpm while at idle under a load and yet,your engine does not stutter.<br />The oil mixture jerk-bait mentions is no less important but it is usually a very straight forward 1 part of oil to 50 parts of fuel.Unless of course, you have a fifties or early sixties engine.<br />Where on our sweet mother earth is Pukalani?

 

[wilde1j]

Re: what does it mean when they say running "too lean" or "too ri

Re: what does it mean when they say running "too lean" or "too ri

rolmops is correct about "rich" and "lean" generally referring to fuel/air mixture, although occasionally some people use the same terminology regarding oil/fuel.<br /><br />Most newer motors do NOT have adjustable mixtures, but have fixed low and high speed fuel metering jets. Usual causes of bad mixtures are carb float valves and junk in the carb. Fuel left for long periods of time (i.e. > one year and outdoors) is a primary cause of crap in carbs along with contaminated fuel (water and debris, rust, etc.).

 

[Beernutz]

Re: what does it mean when they say running "too lean" or "too ri

Re: what does it mean when they say running "too lean" or "too ri

Keep in mind that if you "richen" the oil content of the mixture, it will result in a "leaning" of the air/fuel ratio, which produces a hotter flame in the combustion chamber and potential engine damage.

 

[lc]

Re: what does it mean when they say running "too lean" or "too ri

Re: what does it mean when they say running "too lean" or "too ri

thanks guys! Pukalani is located on the island of Maui,Hawaii.

 

[sloopy]

Re: what does it mean when they say running "too lean" or "too ri

Re: what does it mean when they say running "too lean" or "too ri

aloha!

 

[skeer]

Re: what does it mean when they say running "too lean" or "too ri

Re: what does it mean when they say running "too lean" or "too ri

Interesting point Beernutz but I wonder if the amount of 'leaning' of the air/fuel mixture is significant enough to cause the problems you mention. Even if you double the amount of oil you are only displacing 2% (at 50:1 ratio) of the total amount of fuel. <br />I am particularly interested in this as I have just finished rebuilding my engine and completed the break-in period where you double up on the oil ratio. Perhaps I need to reset my carbs as I would now be running excessively rich... hmmm... anyone else with thoughts on this?

 

[Spidybot]

Re: what does it mean when they say running "too lean" or "too ri

Re: what does it mean when they say running "too lean" or "too ri

Skeer: In theory and practise, it's correct.<br /><br />If the effect during normal use will cause problems is another thing. Running hi-performance setups each and every parameter has to be optimized and every little detail gets important.<br /><br />For normal uses, with a motor tuned correctly like yours, I'd say stick to the specified 50:1 and keep an eye on plugs, smoke and general behaviour.

 

[Beernutz]

Re: what does it mean when they say running "too lean" or "too ri

Re: what does it mean when they say running "too lean" or "too ri

Believe me. At the rate of 90 ignitions per second, the combustion chamber will know the difference. And so will the pistons.

 

[Beernutz]

Re: what does it mean when they say running "too lean" or "too ri

Re: what does it mean when they say running "too lean" or "too ri

Skeer, your break-in proceedure should prohibit extended WOT operation while you're using the double-oil mixture. That's really the only time it should cause a problem.

 

[Capt Ken]

Re: what does it mean when they say running "too lean" or "too ri

Re: what does it mean when they say running "too lean" or "too ri

Any rebuilder will tell you that a heavier oil mixture will result in a hotter burn in the cylinders. That's why they only want you to run one tank of double oil when you are breaking in a new engine. FYI, the perfect fuel to air mixture is 14.9 to 1.

 

[slow_boat]

Re: what does it mean when they say running "too lean" or "too ri

Re: what does it mean when they say running "too lean" or "too ri

Have heard that (over-oiling) the premix can only cause fouling of plugs...never heard of hotter burn in the cylinders & other related problems. I must assume that I have been mis-led & being forever curious would like to understand this principle greater. Any 'further reading' recommendations would be welcome.<br /><br />7

 

[durk187]

Re: what does it mean when they say running "too lean" or "too ri

Re: what does it mean when they say running "too lean" or "too ri

This is interesting. I was looking at my seloc outboard manual. Under the topic of spark plug fouling it says that heavy carbon buildup on a plug is the cause of the excess oil cooling the combustion down, not allowing the plug to burn the contamintes off. Any Thoughts?

 

[JeremyC_Florida]

Re: what does it mean when they say running "too lean" or "too ri

Re: what does it mean when they say running "too lean" or "too ri

What actually happens is that there is a OIL residue that builds up.. due to more oil in the gas/mixture. This buildup of unburnt oil causes ...** gunk on the plugs *** Black burnt scarring on the cylinder walls *** and excess heat to build up, which cause other symptoms and problems... Go to any boat shop .. you can pick put the "over oiled" pistons and cylinders at a glance...

 

[Beernutz]

Re: what does it mean when they say running "too lean" or "too ri

Re: what does it mean when they say running "too lean" or "too ri

Never heard that one, Duck. I suppose it could be true at low RPMs. But at anything approaching WOT, it's gonna produce a hotter flame. This is one of the most misunderstood concepts in 2-stroke operation. People think that more oil is better. We learned years ago racing motocross that an oil-rich mix can hole a piston quick, if you don't re-jet for it.

 

[Beernutz]

Re: what does it mean when they say running "too lean" or "too ri

Re: what does it mean when they say running "too lean" or "too ri

Oops, forgot to explain the theory.<br /><br />Your mainjet will only allow a finite amount of liquid to flow thru it. If more of that liquid is oil, less of it will be fuel. It's the air/fuel ratio that determines the temperature of the flame in the combustion chamber. <br /><br />Less fuel = leaner. <br />Leaner = hotter.

 

[Spidybot]

Re: what does it mean when they say running "too lean" or "too ri

Re: what does it mean when they say running "too lean" or "too ri

Just want to add, that the fuel serves as a 'coolant' in the combustion chamber. Less fuel in the mix means less cooling in the process...

 

[sho305]

Re: what does it mean when they say running "too lean" or "too ri

Re: what does it mean when they say running "too lean" or "too ri

And that is why you read your plugs. Darker brown=rich. Medium brown=good. Light tan=getting lean. White=death. Most boat motors run a little rich for a safety margin due to continous high rpm/wide open throttle use.<br /><br />Not that is is good for the engine to have excess oil, but as oil injection design has shown they require little at low speed and more at high rpms. Lots of caked up over oiled motors are from slow running and too much oil that does not get burned out. Lots of oil usually makes them run bad all the time anyway.