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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

franchi said:

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

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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.

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

Rivets said:

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

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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.

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!!!!

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! (-:

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.

Rivets said:

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.

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

bwright1818 said:

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! (-:

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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

Plug colour should be brown to tan.

Hi:

I have looked through all of my Lawnboy service manuals but I did not find any fuel/oil misture ratios. I was under the impression that the correct mix for the plain bearing D 400 engine was 16:1. The correct mix for the F engine is 32:1. Is this correct?

Tia,

Franchi

franchi said:

Hi:

I have looked through all of my Lawnboy service manuals but I did not find any fuel/oil misture ratios. I was under the impression that the correct mix for the plain bearing D 400 engine was 16:1. The correct mix for the F engine is 32:1. Is this correct?

Tia,

Franchi

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The 2 ring piston uses needle bearings at the wrist pin instead of bushings. These bearings did not require the same amount of oil for lubrication and therefore the ratio change to 32:1 .
What is the model number of your lawn boy having the D 400 engine?

Hi:

This is what I just learned about my D 400 engine:

It is a D-408 engine

It should have a"one full can of LAWN BOY 2 cycle oil added to one gallon of gasoline.' How much does a full can of LAWN BOY contain?

My engine has needle barings on the armature side of the crankshaft and on the big end of the con rod. The wrist pin bearing is plain. The bottom bearing is a plain bronze bearing.

Do not use 2 cycle Marine oil!

Use only a brand name of oil such as Lawn Boy in your engines. These oils are sold by the manufacturers of 2 cycle equipment. Perhaps Marvel Mystery Oil is also suitable. These cost more but they have expensive formulations!

Klotz products are also good but are very expensive as is Amsoil products.

Extra oil in the mix will NOT raise the temperature of combustion but will cause the engine to run with LESS heat.

Synthetic 2 cycle oils may not be necessary.

Avoid buying oils that have exotic properties or contents advertized on the container.

I can use the heavy oil mix in my F engine without any problems.

As far as improvements in oils over the years are concerned, they have been improvements in sale hype! The products have not improved. As a matter of fact, some are not as good in some cases as the oils in the past! Can one say "Mouse Milk"?"

Stay well,

Franchi

franchi said:

Hi:
Do not use 2 cycle Marine oil!

Extra oil in the mix will NOT raise the temperature of combustion but will cause the engine to run with LESS heat.
Franchi

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Marine oil is fine to use in you lawnboy.
From what I understand of it, it is less damaging to aquatic life then non-marine branded oils. :confused2:

Extra oil 'will' raise the temp inside the engine. The gas in the gas/oil mixture is the internal cooling mechanism.
Less gas = hotter internal temps. More oil = less gas.

Study this hypnotizing link <gif>

[video]http://i48.photobucket.com/albums/f211/justpinit/Arbeitsweise_Zweitakt.gif[/video]

Hi Why Zed:

My source of information told me that Marine grade of 2 cycle oils are cut with kerosene to make them less viscous in order to be injected into marine engines. Is this a bad thing? He thought so.

He also stated that more oil provided more cooling. The oil removes much heat in a 2 cycle.

Just his training and experience,

Franchi

franchi said:

Hi Why Zed:

My source of information told me that Marine grade of 2 cycle oils are cut with kerosene to make them less viscous in order to be injected into marine engines. Is this a bad thing? He thought so.

He also stated that more oil provided more cooling. The oil removes much heat in a 2 cycle.

Just his training and experience,

Franchi

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gas is the cooling factor and oil is for lubrication

HI:

Thanks for the reply.

Let me reflect about this for a moment.

Gasoline, cool, is converted ino a vapour, cool, this vapour cools the engine and then is coverted into a hot gas,1500deg.F. The hot gas heats the enngine then is exhausted.

The oil is cool remains a liquid, cool, is heated by removing heat from the engine and the combustion process and then is exhausted. Does the oil add to the combustion temperature when it "burns"? Or is the oil heated to a point that is below its ignition temperature and then exhausted removing engine heat? I do not think that the oil burns in the cumbustion process but is heated to a point where it will smoke, If it burned, it would lose all of its lubricating properties! I have seen engines where the oil had burned causing a breakdown in lubricatiion and there was major engine damage.

In my model airplane engines, oil is used to help cool the old style engines. I run at least 28% oil in the old engines and 18% in the more modern engines. The older engines produce more heat due to their design and the extra oil is necessary to remove this excess heat to avoid engine damage.

These are just some thoughts,

Stay well,

Franchi

franchi said:

HI:

Thanks for the reply.

Let me reflect about this for a moment.

Gasoline, cool, is converted ino a vapour, cool, this vapour cools the engine and then is coverted into a hot gas,1500deg.F. The hot gas heats the enngine then is exhausted.

The oil is cool remains a liquid, cool, is heated by removing heat from the engine and the combustion process and then is exhausted. Does the oil add to the combustion temperature when it "burns"? Or is the oil heated to a point that is below its ignition temperature and then exhausted removing engine heat? I do not think that the oil burns in the cumbustion process but is heated to a point where it will smoke, If it burned, it would lose all of its lubricating properties! I have seen engines where the oil had burned causing a breakdown in lubricatiion and there was major engine damage.

In my model airplane engines, oil is used to help cool the old style engines. I run at least 28% oil in the old engines and 18% in the more modern engines. The older engines produce more heat due to their design and the extra oil is necessary to remove this excess heat to avoid engine damage.

These are just some thoughts,

Stay well,

Franchi

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Do you build the aircraft and if so how do you store the balsa wood.

franchi said:

Marine grade of 2 cycle oils are cut with kerosene to make them less viscous in order to be injected into marine engines. Is this a bad thing? He thought so.

He also stated that more oil provided more cooling. The oil removes much heat in a 2 cycle.

Just his training and experience,

Franchi

Click to expand...

Hey franchi, I'm no engineer but I know a couple engineers that are less engine and more eer

That could be true, I've never heard that. I have learnt that marine oil has a lower ash content then low performance, low cost, non-marine branded oil.
If marine oil is in fact cut with kerosene then I would consider it an inferior 2 stroke lubricant than what I am using.
Kerosene is a high performance fuel (jet engines, rockets, 2 stroke engines etc), is a every good parts cleaner and is 'oily' compared to gasoline but not nearly as slippery as the 2 strokes lubes I use..

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kerosene 15hp 2-stroke outboard engine, 246cc displacement, water cooling system, suitable for salt water, 24L&12L fuel tank, View outboard engine, Product Details from Suzhou Parsun Power Machine Co., Ltd. on Alibaba.com


I agree with impalass, it is the amount of gas in the mixture that is the cooling agent and the amount of oil controls lubrication.

Unfortunately our carburetors are not very adjustable. It is the lack of those adjustments that force us to tune our engines by varying the gas/oil ratios (more oil = less gas to air = leaner) (less oil = more gas to air = richer). It is the ratio of fuel to air that our engines consider a rich or a lean mixture not gas/oil ratios.
My F engine actually has a main jet adjustment which is great (fuel to air high rpm).
My D engines have only an air screw adjustment (fuel to air low rpm) not so great.

We should use the least amount of oil we can for a clean, smoke free, low sent burn.
Only use enough lubricant for what is essential to the internal moving parts and not trying to lubricate your boots, wheel bearings and the neighbors rooftops.

If you must uses a 16:1 ratio using cheap oil and the cheapest low-test gas and find your neighborhood full of smoke after a couple laps of your lawn, then please look into a hotter spark plug. A hotter plug might help ignite the gobs of extra oil that doesn't have the low flash point of the highly explosive gas vapors for a complete burn.

Awe, another reason for using the highest octane gas you can get in every 2 stroke? hrmm..

The ONLY way to really confirm your engine is getting proper lubrication is to open up the bottom end! (There is nothing to lubricate in the combustion chamber). The color/condition of the spark plug determines fuel to air mixture and temperature of the plug.

If your bearings & bottom end are to dry but your plug is wet, add more oil to your mix.
If you bearings & bottom end are to dry and your plug is white (lean), add more oil to your mix and change to a cooler plug.

If your bottom end is dripping wet but your plug is white (lean). Reduce oil, & possibly a cooler plug.
If your bottom end is dripping wet but your plug is wet (rich). Reduce oil, & possibly a hotter plug.

Your temperature and elevation play a major role in how your engine needs to be adjusted.
A perfectly adjusted engine tuned in August at Daytona Beach will run dangerously lean in October in Colorado.

etc...

Hi Implaass:

I have not built any model airplanes since 1983. I have over 30 planes hanging in my attic ready to fly when an engine is mounted.

I have stored some balsa in my attic and a number of old kits there also. No damage has happened to either. I also have stored balsa sheets i my basement with no changes to the balsa.

I just got back into flying model airplanes after a stint with shotguns and bird dogs. I still have both. Lol

Stay well,

Franchi

franchi said:

Hi Implaass:

I have not built any model airplanes since 1983. I have over 30 planes hanging in my attic ready to fly when an engine is mounted.

I have stored some balsa in my attic and a number of old kits there also. No damage has happened to either. I also have stored balsa sheets i my basement with no changes to the balsa.

I just got back into flying model airplanes after a stint with shotguns and bird dogs. I still have both. Lol

Stay well,

Franchi

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Automatic shotgun.

Hello:

I do own four semi automatic shotguns. I also own a number of SxS, OU and single shot shot guns. They all seem to have a place for my hunting but I have narrowed it down to a 5 pound 4 ounce semi automatic and a 6 pound SxS for hunting.

Stay well,

Franchi

an old schooler told me the 16-1 ratio on the older Lawn Boys was so you could use regular motor oil as a pre mix.I dont know if there is any truth to that but he had a lot of brick tops.