Briggs 10hp internal engine repair

Discussion in 'Mechanic and Repair' started by topsites, Jan 5, 2008.

  1. topsites

    topsites LawnSite Fanatic
    Messages: 21,653

    My blower today lost all compression, at least that's what it felt like as it shut down, then tried to start it and it would just freewheel...

    The spark plug checked out fine, nothing wrong there, wasn't loose.

    So I pulled the valve cover off, figuring if a rocker had come loose and valves were open.
    Nope, all that looked good, they still moved properly when turning the engine.

    Pulled the cylinder head off next, figuring if the gasket was leaking.
    And here is where it gets tricky, tricky...

    When turning the engine, the piston no longer moves up and down on its own, thou I can still push it down manually, then when cranking the engine it pushes the piston up a bit, and there it stays.

    Before I dismount this engine so I can tear into it, does anyone think it would be easier to just buy a new blower, or is it worth it, for $900 cost, to tear it apart?
    Everything has to be taken off, starting with the shroud, I may not have to pull the impeller but the engine has to come off the frame... Likely looking at 3-4 maybe 5-6 hours until I can get a good peek inside...

    Just wondering what I should do...
    So if anyone has ever torn one apart, some feedback would likely be appreciated.
  2. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    If you want to look inside the engine the impeller must come off, You didn't mention how old or what shape this unit is in ? If it's in good shape why buy a new complete unit if just a engine replacement would get it back up running ?

    I could probably have this engine opened in less than a hour, Maybe 2/3 for a novice keeping at it. If you have nothing better to do (off season) rip it open then install a new engine if needed.
  3. GravelyNut

    GravelyNut LawnSite Bronze Member
    Messages: 1,594

    Broken rod, broken piston pin, broken piston. Any of those are replaceable for less than the $900. Even if you had to go oversize and a honing job. Only when the cylinder is badly damaged, or the crankshaft, does it start looking more economical to replace than rebuild.
  4. topsites

    topsites LawnSite Fanatic
    Messages: 21,653

    Ok, that's about what I decided was to rip into it, worst case scenario I'm out some time, I think something just came off down at the rod end, could be just a nut worked its way loose too but there's no telling until I get in there.

    The unit is 6 years old and works decent, but this briggs engine gives me trouble every single season, soon as I get it working it runs great but sure enough at least once / season this crap!

    I've rebuilt the carb (twice), replaced coil, ignition switch (at least once), throttle cable (twice), cylinder head gasket, installed inline fuel filter, who knows what else but that's on top of the usual spark plugs / air filter etc... Half the reason it still looks good is because just about every single thing has been replaced at least one time lol...

    Not that I'd expect it to run forever, but 6 years is no age to me, not for this kind of recurring trouble, I'd say it ran good for a whole 2 seasons out of 6, it runs all right most of the time but sure enough it always has to start with me.

    I guess it was just something I see coming now, few more repairs like this and it's over but I'll deal with it this one time.
    I know one thing, I am never getting anything with another briggs again, they're just not built for it, and I might reconsider Billy Goat as well.
  5. Roger

    Roger LawnSite Fanatic
    Messages: 5,943

    What kind of B&S engine? Is it an OHV or a side-valve?

    I have an 8hp B&S on my Lesco blower. Probably like yours, it does not run many total hours per season, but when I need it, I expect it to run well every day. Mine is a simple side-valve engine. But, for the number of hours, many things have been replaced (e.g. muffler, muffler bolts, brackets, shroud bolts have come out needing replacing, starter recoil assembly problems). In proportion to the number of service hours, and the items replaced, the B&S is well down on the list for reliability.

    These engines are of marginal quality for this application. There is a balance between a piece of equipment that sits much of the year, but is expected to be reliable when needed, an engine that is down on the list of cost, vs. a more expensive engine that sits idle so much of the year, but works very well when put into service. If I was to use the blower every day, or every other day, throughout the season, I would never buy one with this kind of engine.
  6. topsites

    topsites LawnSite Fanatic
    Messages: 21,653

    OHV Intek, but what you said is exactly my take on it, not worth the savings in trouble over time, even on a part-time machine.

    Which is why I was considering replacing the whole blower, because by the time I put a Kohler or a Honda or something in it the cost is close... But then I just got done replacing our hot water heater, one mower and one car is down, the other car needs a new roof (convertible), every vehicle needs State inspection done and insurance is due before spring too, oh I just got started, the list goes on :laugh:

    In just a few weeks I'll have the time so I'll just save the 900 for now.
    Thanks for all the input, that really helped!
  7. topsites

    topsites LawnSite Fanatic
    Messages: 21,653

    More fun stuff...

    Because on a 4-cycle engine there is the issues with TDC, I didn't see a mark on the camshaft...?

    And Wth is this rod go to?
    Sorry not the best pic because of the flash, that rod on the red rag, almost looks like a pushrod that goes to a car... Maybe it is, but...
    The flash distorted it, it's straight as an arrow and equal thickness all along, outer aluminum cover with rounded steel ends.

  8. Restrorob

    Restrorob LawnSite Fanatic
    Messages: 11,029

    That is the push-rod that runs from the cam tappet to the rocker arm, That along with the other one would be installed after the engine is closed up and head re-installed. Loosen the rocker adjusters to install them.

    The plastic cam gear will have a mark on it such as this "^" pointing at a recessed tooth on the cam gear, This ^ will align with a dot stamped in the crank gear.

    We have talked about finding TDC compression stroke in the past, If you don't remember I will go over it again.
  9. Roger

    Roger LawnSite Fanatic
    Messages: 5,943

    This project looks pretty serious, ... a heavy mallet, and a broken Gator blade. Is this the stuff of which broken engines are made?
  10. topsites

    topsites LawnSite Fanatic
    Messages: 21,653

    Yeah it is a push rod, I found the other one, silly me.

    The only plastic gear I see is the governor actuator, I think all the rest are steel, but I'll take another look at it tomorrow... As you said, an hour flat that engine was off and apart, much beyond that I didn't feel like it so I let it all sit.

    The other consideration I am going to see, if for 4-500 I can just replace the engine... Because it tore that connecting rod to shreds, and it was down to maybe a pint of crude black oil, I'm just concerned it might've done more damage.

    Then I might also get new rings and re-hone, probably run me 1-200 that way and yeah I'll probably need some assistance with TDC compression... I do know something about it, which is my concern... Specifically the crank turns twice per spark, once on the intake-compression stroke, again for the ignition-exhaust part, but the flywheel only actuates the magneto once so it is very important to be on the TDC of compression- TO -ignition or else the camshaft is off 1/2 turn or what have you and it won't work.
    But before we get into this explanation I'll take more precise pics for that.

    LOL, actually that Gator blade is just a flat piece of steel I use to drive bearings, it's an old blade and sometimes I cut them apart when I need a flat piece of steel... The middle section of that blade was used as a 'bridge' to weld my tiller's frame back together a year or so ago heheh

    Old blades are great, I was surprised at the uses for those 1/4" thick pieces of steel, an older gentleman taught me that trick.

    Yup, hold that blade flush flat on top of a bearing and smack it with the big hammer, works great for those things where a wooden block or a rubber mallet just isn't enough. It's still hard on the bearing, but its much better than a steel mallet straight.

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