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Issue setting valve lash B&S Intel V-Twin

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Steverino
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2025/05/07 16:32:57 (permalink)
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Issue setting valve lash B&S Intel V-Twin

Briggs 44577 0264-E1   (Code051121YG)
V-Twin OHV 25hp
271 hours
 
Set intake & exhaust valve lash on both cylinders to .005 with piston about 1/4” past TDC on compression stroke. (Checked 3x on each cylinder) Then went back to check again.
 
Just before the piston came up to TDC on the compression stoke, the exhaust rocker arm was loose on both cylinders and had about .006 play in it. When piston was up 1/4" past TDC valve lash checked again on both cylinders/valves and all was fine.
 
Comments anyone?
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    SRTsFZ6
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    Re: Issue setting valve lash B&S Intel V-Twin 2025/05/07 21:06:16 (permalink)
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    Compression release working as it should..
     
    Watch at about the 8 minute mark:
    https://video.search.yahoo.com/search/video?fr=mcafee&p=briggs+compression+release+which+valve%3F&type=E210US1498G0#action=view&id=10&vid=1fc0e8e35c4fd906c83e8124bf077132 
     
    Your good..
     
    .

    Scott
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    Steverino
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    Re: Issue setting valve lash B&S Intel V-Twin 2025/05/08 01:28:14 (permalink)
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    SCOTT:    First, pls excuse my A.D.D. (Really) But I DO appreciate the "your good".
     
    If I'm watching the same video you referred me to (posted by wtbm123) now I'm wondering if I set the valve lash the right way. First he sets valve lash on the bottom valve (intake) with the exhaust valve open, spins the engine until the intake valve is open then adjusts the exhaust valve lash. I had both valves closed with piston about 1/4" past TDC and adjusted both at the same time.
     
    Never really checked whether or not the compression release was working the way it's explained in the vid.
     
    Reason I'm concerned is when I was done and had the valve covers back on, the engine wouldn't crank enough to start. (Seemed like hydro lock) When I pulled both plugs it spun fine. Put plugs back in then the darn thing started right up. Even started up fine the next day and drove it around for more than an hour. Ran great.
     
    Another concern: The second day I decided to check compression (Penske tester). Cylinder #1 185psi, cylinder #2 175psi. Had to check that twice since it seemed high to me. I know Briggs doesn't publish the compression specs.
     
    Am I "still good"?
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    SRTsFZ6
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    Re: Issue setting valve lash B&S Intel V-Twin 2025/05/08 07:20:43 (permalink)
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    You adjusted them by the book, which of course is fine.  The 1/4" is to make sure your
    past the CR operation.  When the valve is closed, the cam profile is the same and doesn't 
    change.  
     
    You can adjust the valves (or check as well) the one, as long as it's fully closed.
    I've checked both ways and the #'s should be the same.
     
    10 PSI difference between both cylinders is fine, actually very good.
     
    Just to confirm the cam de-compression release is working is to see that little 
    bump when turning over by hand slowly.  It's very slight but is visible.
     
    Cranking over normally also indicates the compression release IS working.
     
    When the engine all of a sudden is very difficult to spin over (on the compression
    stroke) , with no bump indicates the cam compression release issue.. 
     
    Why it was hard to turn initially but fine after that, dunno.  
    If it's cranking, spinning over fine now, I'd move on..
     
    Hope that helps, but you sound like your good..
     
     
     
    .
    post edited by SRTsFZ6 - 2025/05/08 07:30:20

    Scott
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    Steverino
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    Re: Issue setting valve lash B&S Intel V-Twin 2025/05/08 11:33:37 (permalink)
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    Thanks again Scott.  You've given me the confidence I needed.  The true test will be when we get back up to Michigan and I fire up the tractor to cut the grass.  If I feel up to it might check for that little bump.
     
    Still a little concerned about what seems to be high compression readings.  "One day at a time", ya know?
     
    Have a great day!   
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    SRTsFZ6
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    Re: Issue setting valve lash B&S Intel V-Twin 2025/05/08 12:33:48 (permalink)
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    Your compression #'s are great.  
     
    Carboned up rings, leaky valves, etc would show with lower compression, which you don't have.
     
    If you REALLY want to know the health of your engine, you can do a "Leak Down Test". 
    IME, in your case not necessary but an interesting tool to use and detect internal issues
    which you may not see once torn down.
     
    The tool isn't terribly expensive but you will need at least a small compressor.
     
    You basically lock up the flywheel, TDC compression stroke, hook up the tool thru the spark
    plug hole and pump 90-100PSI into the combustion chamber.  Anything generally 85% or higher is fine.
     
    If you HEAR air escaping thru the muffler- you have an exhaust valve leaking.
    Hearing air thru the carb, intake valve issues.
    Air coming out the oil filler tube-piston rings not sealing and air escaping into the crankcase.
     
    IE a very old chain saw brought to me to see if I could fix it. 
    Parts were not available and you could see the results of the test:
     

     
     
     

    Scott
    Quote  #6
    Steverino
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    Re: Issue setting valve lash B&S Intel V-Twin 2025/05/08 16:20:33 (permalink)
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    Good to hear about my compression numbers.  Thanks.
     
    I forgot to take my leak down tester along last month.  It's a slightly modified Harbor Freight unit but it worked fine on push mowers & snow blowers when I used to work out of my garage.
     
    BTW...you answered a question for me some time back on "top no load speed" for the same engine.  A new OEM carb went on the same time I messed with valve lash and to my amazement I hardly needed to make any adjustments.  Didn't even bother with adjusting the "governed idle to 1750 RPM" according to the repair manual.  (It was easier and quicker to pop on a new carb than to clean & rebuild.)
     
    If I remember I'll give you an update after the next trip up North.
     
    Steve
     
     
    Quote  #7
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