Picked up a Lawnboy Silver series 6.5HP 2 stroke.

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Hey Cujet,

Nice plane.
The next time you wish to take out that Cessna to pick up another 2 stroke mower, look around for a Toro Proline with a 2 cycle Suzuki engine. Not quite as strong as the Lawn Boy you have, but "unbreakable" and less temperamental regarding the carb. There is a Toro dealer in Omaha, NE who has a nice business restoring them to like new condition every winter, down the last nut and bolt. However, they don't come cheap. I have one in storage, in Maryland. Landscapers cried nationwide, when the government banned this mower. This would be a nice day flight for you.

Also, look around for the higher dollar versions of the mower you have that were made. Lawn Boy models # 10550 or 10552. They feature the infinite speed, Personal Pace transmission. The 10552, that I own, has electric start is my "daily driver". They will cut the hill down that you mow, down to nothing. I too, vouch for the power of these mowers, I have cut grass as tall as the wheels without it stalling.

The ultimate Lawn Boys that were the 2 stroke ones used by landscapers. Model # 22261. Features include: 1) a bright orange, full 1 gallon gas tank 2) orange wheels and 3) highly sought after 3 speed transmission. I modified mine to accept the orange steel wheels (yes steel) from a newer commercial lawn boy. The net result is you can replace the rear tire tread, and not the entire wheel assembly (when you wear out the tread). A ton of these mowers were sold in the upper midwest states, like Wisconsin and Michigan - near the Lawn Boy plant. Also a lot were sold in hilly areas like West Virginia and Pittsburgh. Very few in Florida, from what I have been told. Tough to find, but that mower has a cult following, among owners.

If you pay top dollar, I will sell you one of mine, and meet you at the Nashville airport. I too use Mobil 2T or MX2t from my stash. No exhaust port drips, no smoke and no odors.
 
Originally Posted By: Slick
Cujet

How much more Mobil MX2t 2 cycle oil do you have stored away?

I used my last quart a loong time ago. Wish they still sold it.

Slick


I think I'm down to my last gallon. I had 4 gallons of the stuff.
 
Originally Posted By: spasm3
I bought a 6.5 duraforce this year. Great power! Mows through anything with out bogging. It does sound cool! I did mix amsoil (100:1) cycle at 34:1 and it smokes a bit, so i think that is a bit much. What does everyone else use for your oil ratio with the modern synthetic 2 cycle oils? I'm afraid to go 100:1 in the lawnboy.


I think the Lawnboy connecting rods don't have good bearings. Some even use bushings from what I understand. So, a lean oil mixture is not a good idea.
 
I'd love a Commercial Lawnboy. I have a Commercial Snapper that I just repaired, a JD Garden Tractor and this LB mower. I'm just going to use the LB for the swale and slopes. The other mower is just too heavy for this and I don't want to ruin it's newly repaired engine by starving it of oil.

Do the commercial ones have a better carb?
 
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I have a 7050 that still runs great after 25 yrs.

Be sure to pull the muffler off and clean it out along with the ports. That will keep it running smooth & quiet too.


LawnTools.jpg
 
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Originally Posted By: Cujet
I'd love a Commercial Lawnboy. I have a Commercial Snapper that I just repaired, a JD Garden Tractor and this LB mower. I'm just going to use the LB for the swale and slopes. The other mower is just too heavy for this and I don't want to ruin it's newly repaired engine by starving it of oil.

Do the commercial ones have a better carb?


If you're referring to the commercial LB's, I want to say it depends on the model? I want to say a few earlier ones had a metal carb, but the later ones went to the plastic. (My commercial has a metal carb, but my later 1992 model has a plastic one.. same f series engine though) For the most part, a commercial LB came with the HD orange wheels, larger fuel tank, on/ off switch (rather than an engine brake) and the engine guard.
 
When I was a lid back in the 60's and 70's my family always had Lawn Boys. They lasted forever. The smell of 2 stoke exhaust and grass on the under deck muffler takes me back to my childhood. Every Saturday morning it was my job to lift the mower into the back of my grandma's '65 Malibu and go mow the church yard. I certainly appreciated the light weight. I'm currently using a 20 + year old gold series as a trim mower.
 
Originally Posted By: Cujet

I think the Lawnboy connecting rods don't have good bearings. Some even use bushings from what I understand. So, a lean oil mixture is not a good idea.


Thanks, so is everyone pretty much sticking to 34:1?
 
Originally Posted By: spasm3
Originally Posted By: Cujet

I think the Lawnboy connecting rods don't have good bearings. Some even use bushings from what I understand. So, a lean oil mixture is not a good idea.


Thanks, so is everyone pretty much sticking to 34:1?


I'm using 32 to 1, synthetic oil. Just verified the connecting rod big end bearing is simply a shell bearing (bushing) , not a roller, like most 2 strokes. It's very important to use the correct oil ratio in these engines.
 
Originally Posted By: Cujet
Originally Posted By: spasm3
Originally Posted By: Cujet

I think the Lawnboy connecting rods don't have good bearings. Some even use bushings from what I understand. So, a lean oil mixture is not a good idea.


Thanks, so is everyone pretty much sticking to 34:1?


I'm using 32 to 1, synthetic oil. Just verified the connecting rod big end bearing is simply a shell bearing (bushing) , not a roller, like most 2 strokes. It's very important to use the correct oil ratio in these engines.


Thanks, I never knew some late model 90's Lawn Boy two strokes did not use needle bearings in the connecting rod big end after they switched to them in the early 60's. You should be using 16:1 on these models. All other Lawn Boys with needle bearing big ends can use 50:1 with today's oils except Amsoil which can be used up to 100:1.
 
If I could ever find one of these mowers locally, I'd grab it. As much as I like my Snapper commercial 21", it's HEAVY.
 
I had to look. And sure enough, I see an auction on eBay right now for a Duraforce conrod with shell bearings. You really do learn something new every day. I had never heard of a Lawn-Boy engine that didn't use needle or ball bearings everywhere. Even the much-hated V-series engines used needles here.

My 1987 model 8157 uses a metal Walbro carburetor. I don't think the plastic carburetor is necessarily any worse, but you do have to watch out for warpage. The mounting ears like to curve inward and that will break the seal at the back of the crankcase. If you do switch to a Walbro in the future, be sure to use mounting gaskets (and heat shield) that keep open the little transfer port at the top of the reed plate. The plastic carburetors don't use that, but the metal Walbros do.

I must agree with others here; I wouldn't run that engine any leaner of oil than 32:1. I think I can do 50:1 in my Fs, but I have not yet. Maybe next year.
 
Originally Posted By: Hokiefyd
I had to look. And sure enough, I see an auction on eBay right now for a Duraforce conrod with shell bearings. You really do learn something new every day. I had never heard of a Lawn-Boy engine that didn't use needle or ball bearings everywhere. Even the much-hated V-series engines used needles here.

My 1987 model 8157 uses a metal Walbro carburetor. I don't think the plastic carburetor is necessarily any worse, but you do have to watch out for warpage. The mounting ears like to curve inward and that will break the seal at the back of the crankcase. If you do switch to a Walbro in the future, be sure to use mounting gaskets (and heat shield) that keep open the little transfer port at the top of the reed plate. The plastic carburetors don't use that, but the metal Walbros do.

I must agree with others here; I wouldn't run that engine any leaner of oil than 32:1. I think I can do 50:1 in my Fs, but I have not yet. Maybe next year.


Hey, I had to look at that connecting rod on e-bay for myself and I can tell you I'm more than a little embarrassed to find out some late models didn't use needle bearings, especially since I've been collecting Lawn Boys and parts for 20 years!
 
Not using needle bearings in two cycle engines isn't a good idea. I've heard of small two cycle RC engines using bushings but never in a machine intended to perform work.

Unless the industry has come up with special metals and/or lubricants that will provide the same level of durability, I'd avoid any two cycle engine without needle/roller/ball bearings everywhere. NO BUSHINGS! Period.

My take is that the industry probably knew that the two cycle engine would be phased out in lawnmowers and took the cheap route of using bushings. After all, how long would they need to last if they're ceasing production? Dumb idea to phase out two cycles to begin with and even dumber to not build them correctly.
 
Originally Posted By: boraticus
Not using needle bearings in two cycle engines isn't a good idea. I've heard of small two cycle RC engines using bushings but never in a machine intended to perform work.

Unless the industry has come up with special metals and/or lubricants that will provide the same level of durability, I'd avoid any two cycle engine without needle/roller/ball bearings everywhere. NO BUSHINGS! Period.

My take is that the industry probably knew that the two cycle engine would be phased out in lawnmowers and took the cheap route of using bushings. After all, how long would they need to last if they're ceasing production? Dumb idea to phase out two cycles to begin with and even dumber to not build them correctly.


I agree on all counts. It seems the commercial engine also uses bushings. From what I read on another site, one commercial operator got 6 months continuous use from his engines, then would use a short block (fairly cheap) to repair and keep going.

Not sure on his choice of oil or ratio. I know some of the older lawnboys required 16 to 1 and mowing in a cloud of two stroke smoke was the result.

I think mine may have a catalytic converter on it. It really has no smoke or smell once up and running.
 
Mine only really smokes on warm up, and after that its not visible at all and mine doesn't have a cat in the exhaust. I run 32:1 esso easy mix in everything which seems to be a decent oil. We have a couple dozen trees and shrubs scattered on our hilly lawn, so this type of mower is really the only one that works for me.
 
Originally Posted By: Cujet
I think mine may have a catalytic converter on it. It really has no smoke or smell once up and running.


It really shouldn't smoke once warmed up...at least not considerably. My F engines don't smoke either, though the smell is there...just faint.
 
The biggest issue with these engines seems to be how lean they run. The heat just demolishes them. Simply swapping the main jet on the side of the carburetor with the R-Tek main or tapping out the existing one keeps them running much cooler and eliminates the surging. You generally don't even have to touch the pilot even though you can go slightly larger. I also up the RPM to ~3200 to increase blade speed and rev up response in high grasses.

I put about 50 hours this year on my one Duraforce running at 80:1 on Amsoil and I still had plenty of oil inside the exhaust port. One prime, one pull, one puff of smoke from choke and away it goes.
 
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