Hi, IíM Matt from eSpares.
Now if youíve had problems starting your petrol lawnmower, youíll know just how frustrating
that can be. Iím going to run through some of the basic checks we need to go through
to make sure your mower starts first time every time. Now Iíve got a Qualcast classic
petrol 35s but these checks will be applicable for any type of Qualcast, indeed any type
of lawnmower.
Now letís start with fuel. A standard four stroke engine takes ordinary unleaded petrol.
Now the thing about petrol is it degrades over time, it goes off. So if youíve left
petrol in your mower over the winter, the best thing to do is to drain that off first
and put some fresh petrol in there. The two things I want to drain; drain the main fuel
reservoir just by uncoupling the fuel line there and drain that into a bowl. And then,
you can see the carburettor here there is a little release valve there that will just
drain the fuel off the carburettor as well, and then make sure weíve got fresh petrol
in.
Letís check the oil; the dipstick on this Qualcast is on the back here. Just give that
a wipe and pop it back in. I think it looks alright. Yeah, thatís just over half full
thatís fine. If you do need to top up, then top up at the front there. Make sure youíre
using proper lawnmower engine oil. Obviously if yours is a two stroke then use two stroke
oil and then gets mixed directly into your fuel. So spark plug next; standard 14 mm lawnmower
spark plug, and Iím using a 21 mm socket which is specifically for spark plugs. Iím
just going to make sure I donít damage the porcelain or the top of the engine. Weíll
take that out. Spark plugs do have a limited life, itís typically about 150 hours for
this type of spark plug. Now as you can see thereís a spare bit of sooting, fair bit
of carbon on the electrodes there. Itís not actually in back nick, I think weíll just
clean that up with a wire brush and get a bit of fine sand paper between the two electrodes
, just make sure itís all nice and clean. Iím actually going to put a brand new on
in here Make sure youíre getting the right spark plug for your particular mower; theyíre
available for all makes and models on the eSpares website. And then just tighten that
up; not too tight, make sure you donít overdo it. There we go, weíre going to get a good
spark every time now.
So, a few things I just want to check before I fire it up: just the cables, the belts and
the gears. Now if I take off the belt housing cover here, thatís just held into place by
these four hex head screws, you can use a torx bit in there. And if I engage the rear
roller, just make sure that thatís tautening the belt when itís in the on position. Thatís
fine. Likewise if I engage the cutting disc. Yep, thatís putting some tauten in that belt
fine. Just have a look at the belts, make sure theyíre not fraying, no sign of damage
or wear. Theyíre fine. And these gears; I donít know if you can see in there, thereís
actually three nylon gears. They can actually break quite easily, and you can see a colleague
of mine actually replacing those in another video. By that all looks fine.
Now if I just check the throttle; so in the fully off position, you should be able to
see that just cuts the power to the spark plug. Thatís fine. And then as I open the
throttle, you should be able to see itís just opening the carburettor there. If that
needs any adjustment, this little screw here just changes the position at which it opens
the carb. Ok, letís get it started. Letís push the throttle all the way back, all the
way open. Iím not going to give it any choke because itís quite warm, weíre inside. Obviously
if itís on a cold day youíre going to want to give it a bit of choke. Itís probably
worth showing you actually how the choke works. If I take the air filter off here, you can
see thatís the air filter. And the choke restricts or chokes the flow of air going
into the carb. It just gives us a much more petrol rich mixture going in which is what
we need on a cold day because the ait doesnít mix with the petrol quite so well. Itís a
bit of an awkward height with me here on the table but letís see if we can do it. First
time.
Now if yours doesnít start, the problem is probably going to be in the carburettor. Letís
take a closer look. So before I open up the carb, I just want to disconnect my fuel line
and drain the fuel in the tank down into my cam. Bound to spill a little bit. So with
my fuel line out of the way, and if I just get the air filter out of the way as well,
I just need to drain the remaining fuel just sat in the carb. I can do it on this release
valve here. Now Iím going to get as much paper towel under there as possible, and just
soak that up. There we go, thatís emptying nicely. Ok, letís just open the nut on the
bottom of the carburettor now, and see what weíve got inside. So as I undo the bottom
screw, the float chamber comes away there. Just pop those to one side. And here we have
the float itself. Iím going to push through this hinge pin and then I can pull the whole
of the float mechanism away.
So the two things Iím concerned about are this float piston, it sits on top of the float
there and rises and fall in it, and that letís fuel into the float chamber. Now, the bottom
screw that we took out has fuel jets in there; we are going to need to clean both of these
two things thoroughly. For these jets, Iím just going to run a peace of wire through
there and the one through the middle just to make sure weíve got no debris in there,
and give the piston a good clean with compressed air or you can get a special carburettor cleaner.
Itís also a good idea to spray that cleaner or the compressed air around the rest of the
carburettor. Just check the gasket seal as well, this oneís in perfectly good condition
but if thatís looking bit of a mess than itís probably a good idea to replace that
as well.
Ok, Letís put the carburettor back together. You can see on the float chamber, there is
a shallow end and a deep end. Make sure you get the shallow end where the hinge of the
float goes and then just put the screw back in. Donít forget to reconnect the fuel line
and, of course, put the air filter back on. There we go, top up with fresh fuel and weíre
ready to go. There we go, that should deal with most of the problems associated with
getting your petrol lawnmower to start. Spare parts for Qualcast and lots of other makes
of mower are available on the eSpares website.
Thanks for watching.