Backpack Blower Fix! Replace Piston Rings to Restore Compression

Backpack Blower Fix! Replace Piston Rings to Restore Compression


Hello everyone. You have tuned in Buckwsr Weaser coming at you today with another small engine repair project. Laid
out here on my desk are the components to a Troy Bilt backpack blower, 25cc, it’s
model number TP25BP, and the issue that we are trying to do today is to
install new piston rings on the on the piston. I should mention the problem was
a lack of compression, it wouldn’t start. It’s getting spark. I believe fuel flow is
no problem, but it’s just does not have sufficient compression. And what I did
was to take it apart, remove the cylinder head, and here we have access to the the
piston. Look at that little guy – just a little little baby baby piston. And
because of carbon build up the piston rings were pretty much just, uh, you know
frozen into the grooves. And what I’ve done is…I have taken out the the old
rings. I could not get them out without them falling into many little pieces.
I’ve cleaned out the carbon as best I can from these grooves, and now we’re going to go about installing a new set of
piston rings. And I said if you were…. The problem was that parts are hard to
come by, so I was looking online, online all over the place trying to find new
piston rings. I couldn’t find them, they don’t make them anymore, out of stock, unavailable. But then finally I found someone -an ebay seller in
Athens, Greece who was offering these piston rings. So here’s the package. It
arrived the other day. Here they are, taped to this piece of cardboard. Look at
that, isn’t that awesome? Look at these little guys. So today we’re going to try to install these piston rings here on the on the
piston, and hopefully that’s going to be the main job necessary to restore
compression to this engine and get it back in service. Got my my piston ring
expanders / pliers, and we’re gonna see about doing this. It may be hard to see,
but on each of the grooves where the rings are to be installed there is a
notch. For instance, you may not be able to see
it, but there’s a notch right there and then at another spot the notch for the
other ring, and that is where the opening of the ring is going to be installed. And
I guess that is for a reason, so I am going to try to do that as best I can so
as to give myself the best chances of succeeding with this project. Alright,
so hopefully I can do this without ruining the rings. I put them in the pliers
to open them up a little bit sliding them down in place…. I’m trying to line it up with that… with that
notch the in the ring. Like I was saying, the groove. Now I don’t even see it, and I do have my glasses on. There it is. that’s the little notch. So the opening to
the ring is going to be right there. And then the notch on this one is up
here. The fun part will be sliding these… the piston back up into the into the
cylinder head which we have here. One step at a time. Okay, so there’s a an arrow on the top of
the piston, and I believe that’s indicating the the direction towards the
the intake. But of course the reason I know that is… we’ve got the flywheel here,
and the coil still mounted here, so they have to come together. So hopefully I can
figure out how to get this together… while keeping the rings in their correct
grooves. Okay, so we’ve got the rings on, and the
cylinder has slid back into the cylinder head, and now we are going to attach the
head. It’s really just two bolts with an allen key-type screw heads. We’ve got
the one started on that side. Alright, I want to put a little more torque on those bolts. I’m gonna grab this allen key with a pair of pliers. There’s one side. There’s the next side. And I think we have accomplished our objective. So the piston is sliding up and down there. You can see it through the intake hole there. And now it’s the matter of putting this
engine back together and seeing if we can fire it up. So I’ll I’ll take those
steps off camera, and I’ll bring you back for the big start-up. Alright, so the backpack blower is put together here on my office floor,and before we add fuel and try to fire it up, I want to take a reading on the compression now that
we’ve replaced the piston rings. I have the spark plug removed and I’m
going to hold the…. I have an assistant with me who will help
by pulling the starter cord, and we’ll see what kind of…. give it about four or five quick pulls. Go ahead. Okay you can stop there. Alright I don’t know if you can see
that… it looks like about 70psi. I’m not convinced that’s any improvement from
what we had before. Well in spite of the fact that I was not getting the compression readings as I was expecting… the machine is running. Take a look. which confirms to me that we did go
about the the repair project in the right way, and the problem once those
those frozen carbon buildup all over those old piston rings. And the new set
of piston ring seems to have solved the problem. I’m kind of wondering if maybe my my cheap Harbor Freight compression tester is possibly faulty, because I haven’t
been feeling too good about it in the few times that I’ve used it. Well, you get
what you pay for. But it feels good to have solved the problem and got this
thing running again. That feels just like really satisfying. I’m Buckwsr Weaser. Thanks for watching. I hope this video is of help and interest to you. Please subscribe to my
channel. Check out some of my other small-engine videos, and have a great day
everybody. Bye.

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