I'm looking at buying from a friend a late-1990s Lawn-Boy with a Tecumseh LEV120 6.25 hp engine (that probably doesn't run). I've always kind of liked the small Tecumsehs...just because they were a little different, had a higher-pitched "snap" to the exhaust note, and the vertical shaft ones had pressurized oiling (but no filter). I also liked the primer bulb vs. a choke, especially an automatic choke. May I assume that the crank just uses standard bearings instead of needle rollers or ball bearings? And may I assume that it's an aluminum bore engine rather than one with an iron liner? To my knowledge, these have never been considered commercial quality engines, but I still don't know a whole lot about them.
Any Tecumseh L-head experts?
- Thread starter Hokiefyd
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I know they like 20W - 50, I had one for 20 years. The body of the Fears and Sawbuck mower rusted out first.
JTK
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Originally Posted By: Hokiefyd
May I assume that the crank just uses standard bearings instead of needle rollers or ball bearings? And may I assume that it's an aluminum bore engine rather than one with an iron liner?
Sounds right to me.
Even the small push mower engines had pressurized lube? I wasn't aware of that.
May I assume that the crank just uses standard bearings instead of needle rollers or ball bearings? And may I assume that it's an aluminum bore engine rather than one with an iron liner?
Sounds right to me.
Even the small push mower engines had pressurized lube? I wasn't aware of that.
From the Partstree diagram, it looks just like the one on my 2006 LawnBoy. Nice little engine. Burns a little oil on the 10W-40, but it sure likes the G-Oil 10w30 from HomeDepot. No problems with the carb on mine, and I didn't treat it very well before I became a member here.
I didn't know they were pressurized lube. I thought that only happens with an oil filter included?
Incindently, they used to make them about 30 minutes from my house in New Holstein, WI. Yep, they named the town after a type of cow.
Sure enough, the L-Head service manual says all vertical engines are pressure lubed. Page 77 in the PDF.
http://blog.survival-goods.com/LIBRARY/Manuals/Tecumseh-Service-Manual.pdf
I didn't know they were pressurized lube. I thought that only happens with an oil filter included?
Incindently, they used to make them about 30 minutes from my house in New Holstein, WI. Yep, they named the town after a type of cow.
Sure enough, the L-Head service manual says all vertical engines are pressure lubed. Page 77 in the PDF.
http://blog.survival-goods.com/LIBRARY/Manuals/Tecumseh-Service-Manual.pdf
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JTK
$100 Site Donor 2025
Originally Posted By: threeputtpar
cin
I didn't know they were pressurized lube. I thought that only happens with an oil filter included?
Even most of those are splash lubed, with a pump that only pushes oil through the filter and back to the sump.
cin
I didn't know they were pressurized lube. I thought that only happens with an oil filter included?
Even most of those are splash lubed, with a pump that only pushes oil through the filter and back to the sump.
Yes, they do have pressure lube. Well, to at least some parts of the engine. From the Tecumseh L-head service manual:
Quote:
All vertical shaft engines use a positive displacement
plunger oil pump or rotary type oil pump. Oil is pumped
from the bottom of the crankcase, up through the
camshaft and over to the top main bearing. Oil under
pressure lubricates the top crankshaft main bearing and
camshaft upper bearing (diag. 6).
On all Tecumseh vertical shaft 4-cycle engines, the oil is
sprayed out under pressure through a small hole between
the top camshaft and crankshaft bearing to lubricate the
piston, connecting rod, and other internal parts (diag. 7).
The plunger style oil pump is located on an eccentric on
the camshaft. As the camshaft rotates, the eccentric
moves the barrel back and forth on the plunger forcing
oil through the hole in the center of the camshaft. The
ball on the end of the plunger is anchored in a recess in
the cylinder cover (diag. 8).
Pressurized oil does flow to the top crankshaft bearing and the top camshaft bearing, and is misted to other internal parts. Though the narrative doesn't say it, the diagram shows an oil passage within the crankshaft, from the top bearing to the connecting rod bearing. So it appears that the big end of the connecting rod is pressure-lubed as well.
The service manual is kind of vague on engine construction though (regarding iron liners, etc).
Quote:
All vertical shaft engines use a positive displacement
plunger oil pump or rotary type oil pump. Oil is pumped
from the bottom of the crankcase, up through the
camshaft and over to the top main bearing. Oil under
pressure lubricates the top crankshaft main bearing and
camshaft upper bearing (diag. 6).
On all Tecumseh vertical shaft 4-cycle engines, the oil is
sprayed out under pressure through a small hole between
the top camshaft and crankshaft bearing to lubricate the
piston, connecting rod, and other internal parts (diag. 7).
The plunger style oil pump is located on an eccentric on
the camshaft. As the camshaft rotates, the eccentric
moves the barrel back and forth on the plunger forcing
oil through the hole in the center of the camshaft. The
ball on the end of the plunger is anchored in a recess in
the cylinder cover (diag. 8).
Pressurized oil does flow to the top crankshaft bearing and the top camshaft bearing, and is misted to other internal parts. Though the narrative doesn't say it, the diagram shows an oil passage within the crankshaft, from the top bearing to the connecting rod bearing. So it appears that the big end of the connecting rod is pressure-lubed as well.
The service manual is kind of vague on engine construction though (regarding iron liners, etc).
I know the 4.5HP one on my lawn boy runs great yet, although I find I have to hit the primer more than 5 times when cold. Once hot, it starts the first pull every time. mine is from 94 or 95. Friend at work gave it to me when we bought our first house 2 years ago. I went to change the oil when I got it and got maybe 2 table spoons of oil out of it. he didn't take care of it at all and freely admitted that he went right over top of rocks and tree roots with it, and the blade looked like it too
only gives a slight puff of blue smoke at start up when cold, not bad for the lack of oil in it when I got it I've been told valve guides wear pretty quickly on them.
only gives a slight puff of blue smoke at start up when cold, not bad for the lack of oil in it when I got it I've been told valve guides wear pretty quickly on them.Some small engines use an oil pressure based governor system insteadof the "vane" type.
Tecumseh made excellent durable small vertical shaft L-head engines that last a long time with minimal maintenance and few repairs. Too bad they went under!
I have never seen a cast iron cylinder liner Tecumseh engine on a Lawnboy consumer mower, so you are probably right assuming that it is an aluminum bore engine. There isn't anything wrong with aluminum bore engines used in normal residential non-commercial environments. In fact, they will last just as long as cast iron liner engines when used like this.
Besides having a rudimentary oil pump system, they also have a mechanical governor. The mechanical governor gives much better/quicker response to changing load conditions. In addition, they don't use pressed-in valve seats which can come out, the valve seats are one piece and cast into the engine block. Also, their cooling systems are not prone to clogging-up and causing overheating problems.
IMHO, Tecumseh manufactured the best small vertical shaft L-head push mower engines. But, their OHV engines and larger rider engines were another matter.
I have never seen a cast iron cylinder liner Tecumseh engine on a Lawnboy consumer mower, so you are probably right assuming that it is an aluminum bore engine. There isn't anything wrong with aluminum bore engines used in normal residential non-commercial environments. In fact, they will last just as long as cast iron liner engines when used like this.
Besides having a rudimentary oil pump system, they also have a mechanical governor. The mechanical governor gives much better/quicker response to changing load conditions. In addition, they don't use pressed-in valve seats which can come out, the valve seats are one piece and cast into the engine block. Also, their cooling systems are not prone to clogging-up and causing overheating problems.
IMHO, Tecumseh manufactured the best small vertical shaft L-head push mower engines. But, their OHV engines and larger rider engines were another matter.
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