My Lawnboy smokes too much!

franchi

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Hi:

My 1971 Lawnboy requires a 16-1 mix. The only problem is that the exhaust smokes clouds the neighborhood. It is quite embarrasing for us to cut the lawn.

How can I cure this problem? and still maintain a 16-1 mix?

I have been using Lawnboy oil and Sthil oil. No cheap or marine grade oils have ever beeen used in this engine. Perhaps a synthetic oil by Klotz or a motorcycle oil would not burn duringg operation.

Suggestions?

Tia,

Frustrated
 

jp1961

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I'd try 32:1. Is there a needle adjustment on the carb?,,,it may be running way too rich. Tell your neighbor's the smoke keeps the mosquitoes away,,,LOL.

Jeff
 

franchi

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Re:How to adjust the carb on a 1971 Lawnboy?

Hi All:

I adjust the carb on my 1971 LB by turning the adjustment screw in until the speed begins to decrease due to being too lean. I then turn the adjustment screw out until the engine begins to decrease from being too rich. This gives me a "range" of adjustment.

In the past, I turned the adjustment screw to the centre of the "range" thinking that this would be the perfect adjustment.

Recently, I adjusted he carb to run as fast as possible in the lean mode and then back the adjustment off until the engine begins to break into a solid 4 cycle until a load is encountered. It then breaks into a 2 cycle again while under a heavy load. It then goes back into a 4 cycle mode while under a light load.It wil do the 4-2-4 break this way. Is this a good way to adjust a LB

I may go back to running the engine in a slightly rich 2 cycle to see if this helps the smoke problem.

Suggestions?
Stay well my friends,

Franchi
 

jakewells

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try a different brand of oil something that is either smokless and says JASO FC or FD if you got a auto parts store near you they should carry it or tractor supply should.
 

beg

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I was advised by an older person who knows way more on lawnboys than I do that the 16-1 mix was to insure proper lubrication when mixing the fuel with regular motor oil.with the new 2 stroke oils out today a 32-1 mix in a 16-1 mower would IMO be okay.I try to mow when humidity levels are lower with a slight wind as to not upset the neighbors
 

Phototone

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Well, there's your problem. Using regular motor oil. You should NEVER use regular motor oil in a 2-cycle lawn engine. It will quickly carbon up the exhaust ports, causing a reduction in power, and smoking. Any good 2-cycle oil mixed with no-ethanol gas (any grade) will work fine, and should alleviate your smoking.
 

beg

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I can gaurantee nobody on this forum mixes reg. motor oil with gas to run in a two stroke mower.What I meant to explain was BACK IN THE DAY the 16-1 ratio was used to cover such a practice in the case of no 2 stroke oil was available.It will work but do exactly what you stated in your post.I have seen an idiot mix 10-30 motor oil with gas using a 32-1 ratio in a d motor international lawnboy and blew it up.too bad to as it went to the junk before I could get it
 

Phototone

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I can gaurantee nobody on this forum mixes reg. motor oil with gas to run in a two stroke mower.What I meant to explain was BACK IN THE DAY the 16-1 ratio was used to cover such a practice in the case of no 2 stroke oil was available.It will work but do exactly what you stated in your post.I have seen an idiot mix 10-30 motor oil with gas using a 32-1 ratio in a d motor international lawnboy and blew it up.too bad to as it went to the junk before I could get it

Well, thats a relief!!
 

bwright1818

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I had an F engine that smoked too much, no matter how I adjusted it. Ports were clean. I took the advice of someone, either on this forom or the tractor one, and baked the heck out of the muffler on my gas grill. I banged out all the power and that mower never ran so well, with less smoke, too. Note: You will need to clean the grill big time, after doing this, if you intend to cook with it again. I am considering getting an old grill, just for this purpose.....
 

LB8210

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16 to 1 is required for pre 1972 models because they were not equipped with needle bearings on the piston end of the rod. Using any less will cause the piston to wear out the hole for the piston pin. Modern oil will not prevent this from happening at a 32 to 1 ratio in pre 1972 motors. Use the correct amount of oil as stated by the Lawn Boy engineers that designed the motor, depending on pre 1972 16to1 motors or post 1972 32 to 1 motors.
 
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