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What is the typical compression (PSI) on a push mower? Model 128T02-1270-b1

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someolfart
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2020/05/16 20:47:41 (permalink)
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What is the typical compression (PSI) on a push mower? Model 128T02-1270-b1

Sears mower: 917.370670
Engine ID: 128T02-1270-b1
Code: 10102559
DOM: October 2010

I'm looking for the typical or average compression (psi) on this engine? NOT the compression ratio... the PSI.
I know Briggs hasn't released any PSI information, so I'm hoping someone else might know?
I was given this mower. It currently doesn't run, but it tries to. Pretty good bet it's a dirty carb. In fact, it appears the engine was run without a proper air filter. The carb was VERY dirty with caked-on crap on the intake side, so I'm guessing the internal parts took a beating.

I checked the compression and it was 35psi.
I understand these engines have a compression release at startup, so I know the pre-start reading doesn't necessarily reflect the actual engine condition like a car engine would.  At 35psi, that seems awfully low, but I could be wrong. Thus the reason I'm asking before I start prepping for a re-ring, etc.
 
PS: I've found multiple parts for this engine. Could someone confirm the gasket kit and rings for this engine? It's been a long time since I've overhauled a lawn mower (I'm old-school and do older car engines and snowmobiles mostly). Not sure if I should just toss in new rings, or get a piston too? It's hard to say on this newer stuff. Sometimes you can't re-use the parts, or it's not recommended.
 
Thanks
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    AVB
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    Re: What is the typical compression (PSI) on a push mower? Model 128T02-1270-b1 2020/05/16 21:00:13 (permalink)
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    Usually with an active ACR the compression are between 65-100 psi depending well it is working.
     
    As far as overhauling they are too expensive vs replacement costs to do. Thing s carburetor and valve repairs is about all that is worth doing nowadays.Just the .020 oversized piston and rings is $70 retails plus another $27 for gaskets.
    And a new replacement 128M02-0134 is only $159.
     
    Being 10 yrs old it is a good chance that the compression problem is a valve clearance problem.
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    someolfart
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    Re: What is the typical compression (PSI) on a push mower? Model 128T02-1270-b1 2020/05/17 04:04:31 (permalink)
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    Thanks for your reply AVB...
     
    Hmmm.. I was considering another engine instead of re-working the one I have, but most I've seen are near the $300 range. Maybe I'm just not searching right, or not in the right place?  Where can I find a comparable engine for $159? For that price, you're right, my old engine isn't worth the hassle to tear it apart.
     
    The rest of the machine is in great shape and it's a self-propelled. That's the only reason I'm considering fixing it.
     
    UPDATE:
    I found the web site that has the $160 engines. I guess I wasn't looking in the right place. DOH!
    So the 128M02-0134 is a direct replacement for my 128T02-1270-b1?
    Mine has the auto choke/throttle which I really don't care for and would like a manual control. Call me old school... some things just shouldn't be automated (IMO)! Just more stuff to go wrong.
     
    Thanks
     
     
    Thanks,
    post edited by someolfart - 2020/05/17 06:06:52
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    AVB
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    Re: What is the typical compression (PSI) on a push mower? Model 128T02-1270-b1 2020/05/17 07:08:47 (permalink)
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    No since yours has 25mm x 3-5/32" PTO shaft and the 128M02-0134 has a 7/8" x3-5/32" PTO shaft. Sorry I was using the pricing for cost to repair vs replacement but here is the pricing that I found on the exact replacement and a upgrade.
     
    128T02-1270-B1 superseded to 128M02-0025 then superseded to 104M02-0196-F1 per Power Distributors my Briggs parts distributor.
     
    Lowest price I found on it with free shipping is $183.95 163 cc engine
    https://www.ebay.com/i/33...A69EAYYAyABEgKv4fD_BwE
     
    or up size the engine to 125P02-0012 for $237.90 190cc engine Fixed Speed
    https://www.ebay.com/p/26...QeJEAYYAyABEgLDSfD_BwE
     
    I hear you the automation but this is what the manufacture designing these days. I was too happy about the throttle-less engines when they first came out either.
     
     
     
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