Does anyone know why Briggs made the L head engine 190cc engines and called them 6.50, 6.75, 7.00, 7.25 etc.?

bertsmobile1 said:
It is all about the logistics costs.
So you typically have 4 to 5 Hp ratings per capacity.
IF the difference is just a gasket or main jet then the logical thing to do is only supply the biggest one .
IT costs the same to make a 120 main jet as it does to make a 125, 130 135 145 but it costs 5 times that much to warehouse & distribute 5 different main jets and then you have all that slow moving dead stock sitting there , taking up 5 bins costing money , requiring stocktakes + the inevitable miss picks .
This is one of the very big reasons why Chinese stuff is so cheap, they do not supply spare parts for most of the stuff.
Whole engines or nothing .
BRiggs probably looses $ 10 on every main jet they distribute
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As long as we're getting the biggest/best for replacement. A more powerful engine is ok with me.
 
Hey guys, I have the Quantum L-head (6.5) 12H802 on my Toro.
I bought this in Aug. 2000 , cut more than it's share and still cutting grass today.
It probably could use piston rings or needle bearings (if it has them) , wondering if it is worth putting $ into it ?
cost estimate ?... thanks
 
lizzrd said:
Hey guys, I have the Quantum L-head (6.5) 12H802 on my Toro.
I bought this in Aug. 2000 , cut more than it's share and still cutting grass today.
It probably could use piston rings or needle bearings (if it has them) , wondering if it is worth putting $ into it ?
cost estimate ?... thanks
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You only have the first part of the engine model listed, but from what I can tell from the number you gave (and experience with walk behind mower engines) you don’t have needle bearings for the crank. Probably plain bearings. A set of piston rings is about 20 dollars. So pretty cheap, assuming you’re doing it yourself. If you want it done professionally/by mechanic you’d be better off buying a new engine lol. Doing the rings on an engine is a lot of labor.
my recommendation is that if it ain’t broke, don’t fix it. You didn’t say if it’s having any trouble, but unless you notice oil burning off or excess blow by I’d just leave the engine alone and keep taking care of it. In 2000 things were build, well, better than now at least. No OHC 125cc Briggs.
 
thanks for your reply. , uses a little oil , was wondering about oil additive for the rings ? Almost always starts within 1-2 pulls.
, seems like it could run a little more RPM , any tricks there ?
 
lizzrd said:
thanks for your reply. , uses a little oil , was wondering about oil additive for the rings ? Almost always starts within 1-2 pulls.
, seems like it could run a little more RPM , any tricks there ?
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Well for RPMs there should be a spring attached to a tab that controls the carb throttle. If you bend the tap the RPMs will adjust. I don't remember which way you bend it right now but a little experimentation will help.
Here's a picture of the spring and tab. I have the carburetor and fan shroud off but the spring and linkage are there.
spring.png
What you do is start the engine and tie the handle down with something so it runs when you aren't holding it. Be careful of course. Then get pliers and bend the tab. If you bend it one direction and the RPMs increase then keep going that way. If they drop, then go the other way. Do that till you find the right RPM you want. Be warned though that mower engines shouldn't rev much past 3000 for safety reasons, and they're usually set at 2900. I personally don't have a tachometer and I doubt you do so play it by ear. Kinda find a known good mower and pitch match the RPMs. That's what I do. It's not the space shuttle, it'll be fine if it's close to 3000. And of course be very careful when doing this because the blades are spinning and you can't stop it quickly with the handle clamped down. The air cleaner might be in the way so you can temporarily remove it while doing this.

As far as the oil burning I'm facing a similar situation. I recently came upon a free pressure washer with a B/S Quantum 6.5 and all it needed was a carb cleaning. Nice find, but the owner hadn't checked the oil and it was half water half sludge, so the engine is worn pretty badly. It knocks slightly and burns oil quickly, to the point where I have to add 2 oz or so every couple hours. I don't feel like rebuilding the engine because I have a lot of spare engine blocks I could thrown on if it goes bad, and because they're not particularly valuable or expensive. So what I've done is put in some Lucas oil stabilizer to see if it helps. Some say it doesn't, some say it does. In reality it will probably just thicken the oil and that may slow burning or mask wear. Not a fix per say, but helpful. I'd say you don't have much to lose from trying additives but don't expect miracles. If you're dedicated you can tear down the motor and get new rings from Briggs, they do sell them. In fact if you have access to machining you can bore the cylinder out .01 or even .02 inches, hone the cylinder, and buy oversized rings/piston head which Briggs shockingly sells for these tiny engines. That would be the true correct way to repair this engine, but it's really not worth the time/cost unless you have the access to the needed equipment. or are really interested in it. Good luck keep us updated!
 
thanks going to cut grass today so will look at tab/spring.
also noticed when I dug out a couple other blades ( I have 3,
the cutting edge on 1 of them looks to be about 8" while the other two about 6.5" ?
that seems to me it would be a bit lighter in weight therefore turn faster/ easier ?
As much as I would like to bore and rings, with my luck the drivetrain or something else would break .
Never had carb issues, use Seafoam or Mystery oil and Stabile occasionally, same as my other engines.
I also have an old Homelite trimlite that is almost 19 years old and still runs well .
 
lizzrd said:
thanks going to cut grass today so will look at tab/spring.
also noticed when I dug out a couple other blades ( I have 3,
the cutting edge on 1 of them looks to be about 8" while the other two about 6.5" ?
that seems to me it would be a bit lighter in weight therefore turn faster/ easier ?
As much as I would like to bore and rings, with my luck the drivetrain or something else would break .
Never had carb issues, use Seafoam or Mystery oil and Stabile occasionally, same as my other engines.
I also have an old Homelite trimlite that is almost 19 years old and still runs well .
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I don't know about the blades personally, never thought about it. If one is heavier than another it could possibly affect RPMs, although I wouldn't think it would at idle because the job of the governor is to make sure that a consistent RPM is maintained with varying loads.
I would not bother boring. Rings aren't too hard if you have time and a piston ring compressor (cheap on Amazon). If you do rings, then I would advise you to pre-order a head gasket and crankcase gasket because they will likely need replacement and will tear when you take apart the engine. You may want to replace the Crankshaft PTO seal but you should be fine. From what I understand you are experiencing the rewards of taking care of your stuff. 20 year old mower just starting to use oil. Awesome stuff!
 
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