What is the proper oil/gas mix for my two engines?

[franchi]

I have a 1970-71 D400 mower and an newer mower with a F engine. I run 16:1 oil gas in the D400 and 32:1 in the F engine. Is this correct?

To avoid having two cans of different fuel mixes, could I just run both engines on a 16:1 mix? Any damage to the F engine if I do this?

Stay well my friends,

Franchi

 

[impalass]

I have a 1970-71 D400 mower and an newer mower with a F engine. I run 16:1 oil gas in the D400 and 32:1 in the F engine. Is this correct?

To avoid having two cans of different fuel mixes, could I just run both engines on a 16:1 mix? Any damage to the F engine if I do this?

Stay well my friends,

Franchi

Sooner or later you will damage the F engine by using a 16:1 oil gas mixture. you should be using a 32:1 mixture for both engines. I am using a 36:1 mixture with a 2 stroke synthetic oil in both of my F engines and also when i had a 8252 model with a D481 engine.
A too rich mixture actually cause a lean condition in the combustion chamber which will damage the top of the piston.

 

[Rivets]

I would switch to a synthetic 2cycle oil which can be used in both units. I use a product call Opti-2 which I use in 16, 24, 32, 40 and 50/1 ratios. Down to one fuel can. Take a look at this.

2 cycle oil - Opti2, Opti4, and Chemical Rebuild - Premium Lubricants from Interlube International

 

[tlswart]

I would switch to a synthetic 2cycle oil which can be used in both units. I use a product call Opti-2 which I use in 16, 24, 32, 40 and 50/1 ratios. Down to one fuel can. Take a look at this.

2 cycle oil - Opti2, Opti4, and Chemical Rebuild - Premium Lubricants from Interlube International

Thank you for the link on the synthetic. I have wanted to go to a better oil but did not know what to go to. I should have some by PM on Friday.

 

[robinb66]

actually i use 32 to 1 but:thumbsup::biggrin: remember lubrication technology has advanced to awesome proportions over the last 20 years and what we have to deal with now far surpasses what we had and allows us to mix ratio's that we would never have dreamed about using then with no harm!!!!

 

[bwright1818]

I have no scientific evidence to back this up and I don't feel like doing the math...But I do have 20 years of mowing with D and F engines.....An not one power head failure....

I run 24 to one. One pint to three gallons, not rocket science to mix. Very good quality marine TCW-3 oil.

Now, I understand the lean theory. However, my plugs come out rather on the wet, black side, which contradicts a lean running condition. Next time I mow, I am going to take a cylinder temp reading. I bet these things run way hot, so my thought is that, especially when you bog down in heavy grass like I often do, and the cooling air flow slows down, I personally feel better with a little extra lube.

I DO think 16:1 is too much for a needle bearing engine. If it had plain bearings, that would be different.

Again, not trying to cause a big argument...to each his own! (-:

 

[Rivets]

Using a liquid cooled 2 cycle oil (marine) in an air cooled engine will definitely cause wet carbon deposits on your plug. Operating temps are far apart.

 

[impalass]

Using a liquid cooled 2 cycle oil (marine) in an air cooled engine will definitely cause wet carbon deposits on your plug. Operating temps are far apart.

Lawn boy manual recommends TCW-3 oil since a lawn boy is a slow running engine compared to a marine.

 

[impalass]

I have no scientific evidence to back this up and I don't feel like doing the math...But I do have 20 years of mowing with D and F engines.....An not one power head failure....

I run 24 to one. One pint to three gallons, not rocket science to mix. Very good quality marine TCW-3 oil.

Now, I understand the lean theory. However, my plugs come out rather on the wet, black side, which contradicts a lean running condition. Next time I mow, I am going to take a cylinder temp reading. I bet these things run way hot, so my thought is that, especially when you bog down in heavy grass like I often do, and the cooling air flow slows down, I personally feel better with a little extra lube.

I DO think 16:1 is too much for a needle bearing engine. If it had plain bearings, that would be different.

Increasing the jet size increases the flow rate, and vice versa. However, on 2-strokes, the amount of gasoline flowing will vary with the amount of oil added at the pre-mix stage (the oil and gasoline both must pass through the main jet). More oil passing through equates to less gasoline, which equals less cooling.







Again, not trying to cause a big argument...to each his own! (-:

For instance, an engine running cool with say a pre-mix ratio of 32:1 will run hotter (greater chance of seizure) if more oil is added, by changing to 20:1. Therefore, it is correct to say that adding more oil to a pre-mix fueled 2-stroke will make the engine run in a leaner condition

 

[impalass]

Plug colour should be brown to tan.