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Always wondered why there are Briggs 650, 675, 700 series engines that seem identical. They're all 190cc engines with the same carburetors. Why do they have different torque specs? It's annoying when trying to find parts. I guess I can assume parts are compatible.
Does anyone know why this is?

I know briggs makes engines to mower mfgr spec that are basically identical but have a different spec number unique to the mfgr. So you get 20hp, 20.5 hp, 22hp. Engines .There is no law demanding an engine manufacturer put a true measured hp rating on their engines. They can put anything they want. Numbers are usually optimistic. 6.75hp has to be better than 6.5hp. Right?

All engine makers do it for the above reason.
If last years model was perfect then this years model must have bigger engine to be better.
They did a variety of things like different governor springs choke gaskets on the intake and different main jets .
However if a 3 Hp sprint engine powered the mower quite fine what sort of difference is ,5Hp going to make on a 6 Hp engine .
I replace a lot of 20-24 Hp engines with 18 Hp because they are near $ 1000 cheaper and the only thing I get back is it uses less fuel than the old engine.

This resulted from a 2010 lawsuit a couple of manufacturers got caught playing with the HP ratings. Sears would put 23 hp stickers on a rider with a Kohler CV22 or another mower manufacturer had a spring stock up order for a 42 inch 17.5 hp mower but when the dealer got them, they had 15 hp engines and when the dealer contacted his source they sent him 17.5 hp stickers to cover up the 15 hp stickers.

Now by law they have to be measured against a known standard, and also if they change the hp rating on an engine there has to be some change with the engine. A different jet in the carb, or a different camshaft, etc. So this whole thing resulted in Briggs doing away with the hp rating on consumer engines and go to torque ratings. Some companies did totally away with torque and would just post the cc rating of the engine. Honda had to downgrade their hp ratings So the GX390 was 13 hp become 11 hp.

A 190cc motor on a push mower is a good sized engine these days. I see OHV motors just a bit or 100cc. But those ratings are sort of like audio amp power ratings. Lots of those 1000 watt stereos out there. Maybe 40 watts RMS.

I love the BS car stereo amp ratings. Not only do they use peak instead of RMS output and not continuous but instantaneous output and no mention of of distotion. Soooooo, yeah that 1000 watt amp is maybe like ya say 40 watts of something useable.
Same thing for Craftsman air compressor ratings. A 120v 15amp circuit can only provide just over 2 hp. But sears can get up to 6hp on a 120v 15A circuit. They measure instantaneous current draw with locked motor armature. Right before it melts down it drew enough amps to equal 6hp. The marketing wanks of the world are masters at BS. With terms like heavy duty, all natural, new and improved.

ILENGINE said:

This resulted from a 2010 lawsuit a couple of manufacturers got caught playing with the HP ratings. Sears would put 23 hp stickers on a rider with a Kohler CV22 or another mower manufacturer had a spring stock up order for a 42 inch 17.5 hp mower but when the dealer got them, they had 15 hp engines and when the dealer contacted his source they sent him 17.5 hp stickers to cover up the 15 hp stickers.

Now by law they have to be measured against a known standard, and also if they change the hp rating on an engine there has to be some change with the engine. A different jet in the carb, or a different camshaft, etc. So this whole thing resulted in Briggs doing away with the hp rating on consumer engines and go to torque ratings. Some companies did totally away with torque and would just post the cc rating of the engine. Honda had to downgrade their hp ratings So the GX390 was 13 hp become 11 hp.

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I see, they must be making just tiny little changes then like you said, to the point where I don't notice. Silly, isn't it. They don't even make the L heads anymore, which is a shame. Much harder to break, valves never went out of adjustment for me. I miss the sprinter and quantum. The OHV ones seem so crappy compared to the L heads. They are easy to start though.

I have noticed that the new OHV ones are coming in at 125cc to replace the 140cc sprint, and the 190cc has been replaced by something like 150cc. Of course the power is allegedly equal because of improved efficiency with OHV. I don't care, though, flatheads all the way.

Parts in the manufacturing stage are not the same parts that we get as replacement in most cases. They may use 6 different carbs for different hp ratings on the same size engine but will replace all those numbers with a single part number for replacement.Same with camshafts, or ignition modules.

ILENGINE said:

Parts in the manufacturing stage are not the same parts that we get as replacement in most cases. They may use 6 different carbs for different hp ratings on the same size engine but will replace all those numbers with a single part number for replacement.Same with camshafts, or ignition modules.

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That's what I was thinking. Don't like that.

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

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.

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!