Older Mower, new member

[Al-]

Hello everyone!
I have a 21" , around 1979 version. I bought it at a lawn sale perhaps 20 yrs ago. I 've always ran it with a 16:1 mix however it smokes a bit. I was reading in an old manuals that if used OMC oil I could use a 32:1 mix , but otherwise use !6:1. I now buy
modern oil that can be used at a 50:1 mix so I'm wondering if the 16:1 mix using the modern oil might be too rich and the reason for the smoking. Thanks for any advise

 

[steve c]

Welcome to the forum.I'm no expert (there are several members here who are), but I have been running Lawn-Boys for about 35 years and have always used 32:1 with several 2 cycle oils with no problems. I'd start with that mix and see if that helps. From what I've read here, there are other possible causes for the smoke, including carb issues (easy fix). Let us know if the mixture change helps. I'd like to try 50:1 mix myself, but mine only smoke a little, if at all, at 32:1.

 

[DaveTN]

Hi Al and Welcome to the LMF! I've got an old Craftsman chainsaw that uses something like 25:1
and others of later vintage like 32:1... and one Husq chainsaw something around 50:1 I don't know
why these old engines were 16:1, which my dad and uncles used as well as great uncles. I wouldn't
be mixing 50:1 in place of 25:1 just right away because it may cause cylinder / piston wear. As I recall
those old machines smoked like a tar kettle. I have often wondered about the varous mixtures as well. :thumbsup:

 

[Al-]

Thanks for the welcome and input Steve and Dave. My mower well is overdue for some ordinary maintenance , but it just keeps going. I bought a new NGK spark plug and will try the 32:1 mix. The last gas I bought was ethanol free so maybe that makes it smoke more . I only need to mow my lawn a couple of more times this season and I'm working on my snowblowers now but maybe later or this winter I'll work on my lawnboy.

 

[bwright1818]

I always run 24:1, myself. Many, many hours logged this way, with no problems.

I too am working on my snow blowers!!

 

[Phototone]

If you know it is a 1979 model, then it uses 32:1 OIL mix. It shouldn't smoke much if at all, at this mix.

 

[ILENGINE]

The 16:1 engines were before 2 cycle mix was popular or available. It was originally a mix of 8 ounces of 30W non detergent motor oil. 32:1 should be safe in those engines designed for 16:1 if using modern 2 stroke mix.

 

[Phototone]

The 16:1 engines were before 2 cycle mix was popular or available. It was originally a mix of 8 ounces of 30W non detergent motor oil. 32:1 should be safe in those engines designed for 16:1 if using modern 2 stroke mix.

Thats not exactly correct. The Lawnboy models with 3-ring piston and bushing on lower crankshaft (instead of roller bearing) MUST have 16-1 oil ratio regardless of the "type" of oil you mix in. Standard motor oil will create carbon deposits in the exhaust port at a fast rate though. One should always use specific 2-cycle oil.

 

[Al-]

Thats not exactly correct. The Lawnboy models with 3-ring piston and bushing on lower crankshaft (instead of roller bearing) MUST have 16-1 oil ratio regardless of the "type" of oil you mix in. Standard motor oil will create carbon deposits in the exhaust port at a fast rate though. One should always use specific 2-cycle oil.

Interesting !!! How do we identify the 3- ring & piston and bushing models without taking them apart? The one I am using now has a metal frame, I have an even older one with an aluminum frame that belonged my father that at least needs a coil. I think its a 1966, that's the manual I have. I might dig out the mower and check this out later. The manuals lubrication instructions are - use regular grade automotive gasoline- use sae 30 automotive oil a.p.i service ms. - mix 1/2 pint of oil to each gallon of gas. Do not use multiple-viscosity oils (10w30, 20w40)

I've started using ethanol free high test gas in all my small engines to avoid guming up the carburetor instead using the regular grade as recommended in older mowers This gas I would think would burn slower, what other effect it would have I don't know. Maybe I should readjust the carberetor?

 

[Phototone]

Interesting !!! How do we identify the 3- ring & piston and bushing models without taking them apart? The one I am using now has a metal frame, I have an even older one with an aluminum frame that belonged my father that at least needs a coil. I think its a 1966, that's the manual I have. I might dig out the mower and check this out later. The manuals lubrication instructions are - use regular grade automotive gasoline- use sae 30 automotive oil a.p.i service ms. - mix 1/2 pint of oil to each gallon of gas. Do not use multiple-viscosity oils (10w30, 20w40)

I've started using ethanol free high test gas in all my small engines to avoid guming up the carburetor instead using the regular grade as recommended in older mowers This gas I would think would burn slower, what other effect it would have I don't know. Maybe I should readjust the carberetor?

You NEED to use non-ethanol gas, but it doesn't have to be premium. Premium is OK though. You can identify a 3-ring piston engine by taking off the under-deck muffler and looking at the piston thru the exhaust ports as you rotate the flywheel. You can count them. You really, really really should use 2-cycle oil. Not sae 30 automotive oil.