We are WAY too anal on Push Mowers!

Messages
211
Location
USA
I don't know about you guys but I've never had a mower flat out die on me from wear. I'll hit a root and bend the shaft. I'll watch the mower deck rot out. It will get stolen. It will fall out the back of my truck because my brother is a moron. Ect... I've been buying and continue to buy newer model used mowers from pawn shops. Usually $40-$60 for a really nice machine. I almost feel like I could run non detergent 30 weight for infinite intervals because something will happen before it wears out. How bout' you guys.
 
Messages
2,500
Location
Dallas, Texas
The idea is to turn a Chinese made engine that typically will fog out the neighborhood into something that runs kinda nice. Heavier synthetic will do that in a cheapo lawnmower. BTW, I probably need to do what you have done and go shop some Pawn Shops.
 
Messages
14,013
Location
Retired | Wausau, WI
I've not had a chance to have any of these experiences as I'm using the same mower I bought back in 1966. Oh I've rebuilt the carb a few times, replaced the points and condenser a few times, replaced the wheels once, and even overhauled the engine once, but it still purrs right along. The little magnesium deck is still solid and a new coat of paint made it look almost like new a few years back. So, unless it gets stolen, I plan on using it till I die. What is this 43 year old marvel, it's a 1966 Lawn Boy.
 
Messages
2,373
Location
Pennsylvania
Yeah, my Lawn Boy 2-cycle is about 27 years old. I put staorage fogging oil into the spark plug hole every fall, sharpen the blade and clean out under the deck. Still runs like a top every year. I have replaced the ignition system, handle and blade.
 
Messages
7,550
Location
North Alabama
It still amazes me that small engines that run at such high RPM's can last so long. Maybe it's the short stroke??? I've been needing a good push mower for a while for some trim work, but instead of a gas engine mower, I'm seriously considering one of those front blade, human-propelled jobs.
 
Messages
1,087
Location
Germantown TN 38138
 Originally Posted By: wavinwayne
It still amazes me that small engines that run at such high RPM's can last so long. Maybe it's the short stroke??? I've been needing a good push mower for a while for some trim work, but instead of a gas engine mower, I'm seriously considering one of those front blade, human-propelled jobs.
I am sure you are right in saying it's the short stroke. Also, don't forget that a 2-cycle engine is only running half as fast as it sounds like. The rpm is likely not much higher than a 4 cycle, i.e., about 3100 rpm.
 

SnakeOil

Thread starter
Messages
211
Location
USA
2 Cycle engines actually run a little higher on the RPM's but they have less cylinder pressure per revolution. That means less pressure on the rod, crank, bearings, and cam. Less pressure means less wear, but most will agree that the lubrication system of a 4 stroke design is far superior. REVS DON'T KILL ENGINES, LOAD DOES
 
Messages
438
Location
Ohio
If we could not ponder what what is the best synthetic multi viscosity oil to use in our mower, we would have to be out cutting grass. My experience is as yours, even cheap B & S seem indestructible. However, guys have been pointing out how the cheap engines of today are cutting corners on bearings and sleeves. Gas engines will be outlawed by the time these wear out, so you will need to buy a goat or a solar powered mower from LG!
 
Messages
1,087
Location
Germantown TN 38138
 Originally Posted By: SnakeOil
2 Cycle engines actually run a little higher on the RPM's but they have less cylinder pressure per revolution. That means less pressure on the rod, crank, bearings, and cam. Less pressure means less wear, but most will agree that the lubrication system of a 4 stroke design is far superior. REVS DON'T KILL ENGINES, LOAD DOES
I do wonder just how high these Lawnboy 2 cycle mowers revved. I found out that most of them had engines with a 1.5 inch stroke, which would allow for fantastically high safe revs, as far as the engine was concerned, but then you run into the allowable tip speed of the lawnmower blade, and that usually comes out at about 3100 rpm. This rpm in a 2 cycle would sound like over 6000 rpm in a 4 stroke engine. So, my question is: At what rpm do the 2 cycle Lawnboy engines give their commonly rated 6.5 HP?
 
Messages
107
Location
USA
Duraforce (E Series) Bore 2.5000" + .0005 1.75" (44.45mm) Compression 5.8:1 Lawnmower Application Reed Valve 6.5 HP 32:1 2900 RPM Snowblower Application Piston Port 4 or 5 HP 50:1 Fuel / Oil 3700-4000 RPM depending on model.
 
Last edited:
Messages
931
Location
Michigan
....as an engineer the following kills engines...in order of importance... 1.) Poor oil flow upon starting and improper warm-up/shut-down procedures. 2.) Wrong oil viscosity. 3.) Poor lubrication on slopes. 4.) Over-revving or overloading where the govenor is always "working". 5.) Poor quality oil filters. 6.) Not checking oil and letting sump get to critical level. 7.) Hitting heavy debris. 8.) Additives that ruin gaskets and seals. 9.) Condensation or water in gas/oil. 10.) Having an engine that is under-rated for the task. 11.) Aftermaket parts that are poorly matched.
 
Messages
1,093
Location
Kentucky
 Originally Posted By: oilboy123
Agree..........but the objective is to use oil that lets the mower live longer than we will, right?
\:\! Finally. A scholarly gentleman with great knowledge of the engineering, design, and construction, of small single/twin cylinder, air cooled, internal combustion engines, and the special lubrication needs of these engines. It is so great to know there is someone out there that understands why I use full synthetic, motorcycle oils in my two John Deere and my little 5 HP trim mower.
 
Messages
1,007
Location
Dallas, TX
I guess I take it as a personal challenge to see how well my mower will run, and for how long. It requires so little oil to fill it that I have no issue spending money for good oil, and change it often. I did actually witness a mower take a dump at the beginning of a season years ago. A 6-year-old Toro belonging to a friend slung the piston up against the side of their house upon startup. I'm not sure what his maintenance habits were, but I do know he changed the oil in both of his cars religiously at 3K. I tend to think his regimen spilled to his small engines.
 

SnakeOil

Thread starter
Messages
211
Location
USA
 Originally Posted By: punisher
 Originally Posted By: SnakeOil
REVS DON'T KILL ENGINES, LOAD DOES
Physics books and experience might argue that point.
Does physics take into account the direct correlation of engine revolutions to coolant and oil flow? Towing heavy loads out of overdrive causes less engine wear than lugging things around in higher gear. Argue away!
 
Messages
2,439
Location
snowblind in TX
 Originally Posted By: SnakeOil
Towing heavy loads out of overdrive causes less engine wear than lugging things around in higher gear. Argue away!
So we are now arguing something besides small lawnmower engines? "REVS DON'T KILL ENGINES, LOAD DOES" Let us get on the same page. What is your definition of "Kill?" To me "Kill" is running over your crankshaft, tossing a rod out the side of the block, or picking up the last 4" of camshaft laying on your exhaust crossover under your Buick turbo. You are absolutely correct in that "lugging" an engine causes excessive wear on bearings and rings. I don't regard engine "wear" as killing an engine. A runaway 3.5hp Briggs revving 6000RPM unloaded, and tossing it's cookies all over the yard is a "kill". I guess it comes down to definitions.
 
Top