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robleetx

Briggs & Stratton 24 HP thrown push rod - new thread

RobLeeTX
9 years ago

Hi All,

I am starting a new thread for this as I see there was one that spanned from 2009-2013. I have a Craftsman lawn-tractor with the Briggs Engine model 455677 - 0413-E1 two cylinder engine.

If any of you have had an issue with bent push rods or engine backfire and not starting - I have the answer for you.

Mine has had a history of bending push rods on the left Cylinder. this was caused by a stuck Valve. The only way I found to fix this is to replace the Head assembly - which I did about 3 years ago - it ran great until last week. Then same issue even though I had been adding Marvel Mystery Oil to the gas.

Yes - I just ordered another Head Assembly for the left Cylinder. It is still cheaper to replace the cylinder than the whole mower even if I only get 3 years out of it.

Really poor design by B&S!

Comments (13)

  • walt2002
    9 years ago

    Well a lot of people have cured the problem for the cost of a head gasket. I have the fix. Actually, with one fix, you don't even need a head gasket.

    You probably needed to clean your cooling fins, cooling shroud.

    Walt Conner

  • Danny Martin
    9 years ago

    Hi ,I just saw this new thread so I figure I would post my question here as well,I have a manual for my motor but it don't really say much about how tight to tighten the center bolt on valve rockers before making adjustments and if you tighten them up what do you tork them down to.,and it is not clear on procedure on making the adjustments to the rockers, it says to put it on tdc and adjust the intake valve now at this time do you adjust the exhaust one too then do the other head the same,thanks with any help you can give me to clear this up

  • bluemower
    9 years ago

    did your intake valve stick in the guide
    or
    did the valve guide move out of position?

    the bent push rod is a common failure on briggs as well as engines from other manufactures. I have not seen the valve guides moving on other engines however. With the stuck valve, the better repair is to remove the valve to clean the guide. I use a small round nylon brush.

    so here is the question. Does the Marvel oil prevent the gum that forms on valve stems, or are owners better off with fuel preserver and draining old fuel?

  • Danny Martin
    9 years ago

    No had to replace gears inside and rings, when tearing it apart i loosened the bolts to remove rods and heads, put back all togetherand wantd to know how tight the bolt that holds rocker on should be and how to adjust them afterwards

  • tomplum
    9 years ago

    The torque specs, clearances and procedure would be in section 13 of your manual. Ideally use a torque wrench. Otherwise, use common sense. Lock the adjustment nut in place with the set screw and not the other way around. Just a nudge of the nut if you feel you have to. They do break. If you removed the actual stud from the head, clean it well and use red loctite where the stud screws into the head.

  • Danny Martin
    9 years ago

    Thanks Tom, I do have a torque wrench, the actural screw that bolts into head, does that screw down tight to the head and center of the rocker or is there a torque spec for that and the procedure to adjust each rocker says to put the piston on tdc on intake valve and make the adjustment now my other question is do you adjust the exhaust rocker at that time too on each head, this is my first time doing this and want to make sure it is done right thanks

  • tomplum
    9 years ago

    The stud itself 100 " #s. Unless you have a special deep socket, you will need to do this by feel. Again- loctite the stud to the head. Then snap in your push rods and adjust. The manual should indicate 1/4 " past TDC after the intake valve closes. I set the twins at .004" intake and .006 exhaust. Do 1 head at a time as you will have to reset the other cylinder to the proper position.

  • Danny Martin
    9 years ago

    Thank you Tom for the information, if I have any more questions ,I will be back here other wise you all have a great day. You all are the the very best, I am very glad to have found this site ,BEST SITE EVER

  • walt2002
    9 years ago

    I would point out here that the Original Service Manuals did say to adjust the valves AT TDC however, a Service Bulletin came out correcting this to 1/4" down past TDC so OP may have an old manual. Also, the fact that this only happens to the one cylinder is further indication of a cooling problem.as I mentioned above. One Mfgr routed the exhaust too close to one of the heads causing such a problem, don't recall who.

    Walt Conner

    PS: There are at least 3 tried and proven ways to fix a slipped valve guide but buying a new head each time it happens does help the economy.

    This post was edited by walt2002 on Sun, Nov 23, 14 at 15:54

  • Danny Martin
    9 years ago

    Thanks i will note the change in my book cause it does say tdc in mine. not sure what happened to this one but did find an extra exhaust push rod in the case when i took it apart. I got the mower from my sister and they had someone work on it but before i afjust the valve maybe a good idea to take the valves out and check the valve guides to see if they are ok before i close her up or can you tell by just taking the valve springs out.

  • tomplum
    9 years ago

    No need to pull the springs. Just compare the 2 sides whilst the covers are off. If both heads look equally dirty, be extra suspicious. The manuals are all over the place as Walt noted. I think one I have shows the past TDC, but .005 on both!

  • walt2002
    9 years ago

    The newer manual calling for adjusting at 1/4" down past TDC does call for adjusting both valves to .005" which is what I do.

    Walt Conner

  • Danny Martin
    9 years ago

    Thanks Walt, I will look at the heads ,also add these, notes to my manual, really thankful fot your help.

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