RD run all my equipment on Amsoil, but as you advise run it at their max oil to gas ratio for better protection and verify same with plug checks . Sabre for my 2 strokes ( chainsaws , weed eaters , Can Am 370 enduro ) Grizzly 660 quad , Merc 4 stroke 25 hp outboard & all my gen sets on Amsoil premium 4 stroke syn . Pay me now or pay me later ! Good to see u back Bud ! P.S. Still utilize Startron fuel treatment per your recommendation yrs ago .

Sabre is awesome stuff. Can't go wrong with anything with AMSoil in front of the name.

Yep rated for 50:1 to 100:1 ratios , I run 50:1 and great performance and protection 10 yrs with Amsoi l !

ssewalk1, Good to hear from you. Spring is coming in slowly this year. I'll be glad when it's finally here so I can fire up the Lawn-Boy again.

RD , with you on that quite a extended winter ! Hope u chime in from time , lots of new peeps who can learn a lot from your experience Bud !

You have a working 'M'? That has got to be something to behold. But wait, isn't an 'M' supposed to be oil-injection?

Yep , one of the best mowers Lawnboy ever produced . Oil injected however some rumour of issues , so many people ran premix and discontinued use of the injection. My brother had one and ran Amsoil injector oil . He @ my advice ran an ounce of premix in the tank for insurance , that mower still runs well . Piston port design with a pressed crank great performance and durability . Toro had a Suzuki engine that was almost the same design back in the Day . I ran Klotz-R castor oil in it for 10 yrs . Smelled great however you had to decarbon the head at seasons end . No biggy since I was still young and racing snowmobiles at time without any syn oils . Perhaps in his wisdom RD decided to just run premix , I think the injector by design was set @ 64:1 from the factory with a low oil level shutoff if memory serves me . Hope he chimes in to clarify .

I always heard it was the absolute best that old Lawn-Boy (pre-Toro) came up with. Good to know there's still at least one still on the job.

My my Lawn-Boy "M" is a hybrid I built years ago. I bought one that was worn out and got a new engine on Ebay for $10. I also got a rare black Lawn-Boy commercial fuel tank that has no oil tank. They made the whole thing hold gas for a larger fuel capacity. I did disable the oil injection years ago just because I didn't want to run the 64:1 ratio. (Ewalk is correct that it had a low oil shut-off.) I run synthetic oil mixed at rich ratios. Being built about 1989 and self propelled means it was hard to pull backwards. In the mid 90s Lawn-Boy/Toro came out with the wheel ratchets that release when pulled backward. I found a Lawn-Boy with the updated wheel clutches and robbed them for my "M". I had to cut and weld the axle to use them and I was able to retain the Kanzaki Tuff Torq 3 speed transmission. So now when I pull it backwards it rolls with no resistance. I have the factory bagger, mulch plug, and side discharge chute. I recently installed an aftermarket ignition that works perfectly. As ewalk said it may be Lawn-Boy's best ever design. Easy starting, massive power, and a pressed crankshaft with a steel rod. Awesome!

Yes in most cases , your correct . However what RD was referring to is the mysterious Lawnboy Philosphy . More is better . I personally have raced 2 stroke engines for yrs , back when Castor oil was King ! I mixed up to 70:1 in 1979 Evenrude 90 HP V-4 outboard that were rated for 32:1 , water skied with it and trolled for yrs over 12 yrs never an issue . Always used either Opi-2 back then or more recently Amsoil Sabre which is rated from 50:1 to 100:1 . I run all my saws , trimmers @ 50:1 . Some vintage , then rated for 16:1 or 32:1 on Amsoil oil @ 50:1. Back in the Castor days decarbonizing heads and rings & piston was routine due to the limitations of the oils in that era requiring heavier oil ratio,s. Today with modern synthetics lean oil mix can be utilized with superior protection and almost no carbon issues . I even have a small Yamaha 4 HP outboard that was rated for 100:1 and that's what it gets , however I still routinely check plug coloration to verify proper lubrication . So in summary , I run the heaviest oil ratio the Oil Manufacturer recommend not the Engine Manufacturer !

Most cases?

I can't think of any benefits to running higher oil ratios than the oil manufacturer recommendations, that's the point. Can you point to any?? It might seem like the right thing to do, but it doesn't work that way.

On the contrary as mentioned it forms sludge buildup and plug fouling, sticky rings, more frequent maintenance, restricted exhaust, cylinder scoring, etc. The modern lubricants work great at their recommended ratios and help to minimuze this.

Part of the problem too additionally is CARB and other entities that make correct tuning difficult. Altitude, temperature and fuel blends play a big role in the correct AFRs, while the trend is to excessively lean out emissions with fixed orifice or non-adjustable idle mixture or "altitude screw" carburetors. It is pathetic.

I respectfully disagree with Ted. I can show you six or seven Lawn-Boy Duraforce engines that were destroyed by lubrication failures. Two cycle engine lubrication at ratios of say 50:1 or 64:1 is usually ok under normal circumstances but in cases of overheating and overloading the engine may suffer a lubrication failure. Modern synthetic oils do not carbonize the rings, clog exhaust ports, or foul spark plugs. That is the myth. Modern two stroke engines virtually never foul spark plugs from excessive oiling. Rich fuel mixtures and weak ignitions foul spark plugs.

Yes as previously stated " Heaviest Oil Ratio the Oil Manufacturer,s Recommend " But I must agree with RD within Older Lawnboy Theory . You must realize the C Series and early 70,s D Series where rated @ 16:1 and 32:1 Ratio,s perhaps excessive to You but warranted due to the Babbit bearing lower end design in that Era . Leaner oil ratio,s would produce galling under extreme loads and did . However as newer design Full ball bearing construction design later in the newer M and F Series Engines much leaner oil ratios could be safely utilized . Although Lawnboy still recommended 32:1 on most of their product line I have used 50:1 mixed fuel in several newer models over the last few decades . I personally use Amsoill Sabre within all my current 2 stroke engines , this in my mind is the Best current Synthetic 2 stroke oil on the Market . I never have witnessed any carbon issues @ 50:1 or lack of lubricity even @ 100:1 Ratio .

Well stated ewalk

Thanks Bud , just relating real life experiences , as I know you have on numerous occasions ! I agree with what Ted advised within normal 2 stroke oil usage theory , especially when tied within secondary Epa related factors . However it does not ring true with the older Lawnboy mower design as you well know . As previously stated back in my Racing days Arctic Cat recommended 1 quart of their premium grade dino mineral oil mixed to 5 gallons of fuel . I was running a 440 Exterminator free air model @ 50:1 Klotz- R Castor and did so for 3 yrs under severe racing conditions . Routinely tore engine down between races to freshen up the top end for obvious peak performance . Never identified any issues , other than routine light carbon dusting which was normal with castor oils of the time , even at leaner ratio,s . However no galling or scuffing of pistons , which was the norm for conventional oils of the day . Anyhow great to have you back on the Forum Bud . Still have any motor bikes kicking around ?

"I respectfully disagree with Ted. Modern synthetic oils do not carbonize the rings, clog exhaust ports, or foul spark plugs."

Who said anything about modern synthetics?

In any case, I certainly stand by the statement that increasing the the oil & gas mix ratio over the manufacturers recommendation - is somehow beneficial. This has always been a myth, and though well meaning perhaps, a very misguided one. It's not really debateable. It is not a good idea, and anyone who has ever disassembled a 2 stroke subject to this abuse knows why!

"Modern two stroke engines virtually never foul spark plugs from excessive oiling. Rich fuel mixtures and weak ignitions foul spark plugs."

Well we're talking two strokes in general, though they certainly can get fouled if the oil ratio is high enough. It is also very common for people in general to use the gas & oil mix ratio terms interchangeably with AFR, they are not, although excess lubricating oil in the fuel actually leans out the AFR e.g. "I run a rich mixture". Bzzt.

I don't believe we disagree on anything but we have to define our terms. Sorry if I wasn't clear enough.