I have a maculloch 35 classic Briggs and stratton petrol mower and my question is that when ever it runs plumes of smoke come out of the side of it pls excuse my limited knowledge of names and technical terms but its the oppisite side to the fuel filler if you know the model its the left hand side as I look down, I have checked the oil an this is half way up the dip stick, so I wondered where will I find an idiots guide to strippin them down and cleanin the carborettor (excuse the spellin i'm the idiot that will attempt to fix a petrol mower at the age of 36. it will be my first experiance of mechanincing lol so good bye mower you have served me well but who knows where never too old to learn new tricks. any help greatly appreciated. Gavin.

gavin bailey, September 2012

Take out dipstick and wipe it clean. Re-insert the dipstick and remove and check oil level relative to the maximum fill line which is clealry marked on the dipstick. If the level is considerably higher than the highest mark on the dipstick then there is too much oil in the engine and when running the pressure of the engine is trying to disperse the excess oil. You will need to remove the excess oil to the correct maximum fill level and then run the engine for 10 minutes or so to burn of the remaining oil in the exhaust and engine breather system.

pleasant, October 2012

If it's blue smoke, it's either worn out to the point of scrap, or (more likely) it's been tipped on it's side and the muffler is full of oil - in which case it will burn off (eventually - 10 minutes or so).

If the smoke is black, replace the carburettor diaphragm. There are no adjustments possible. Get the diaphragm kit (very cheap), then proceed as follows ;-

1) Remove the air filter (1 long screw)

2) Remove the entire tank/carb assy from the engine (2 bolts - one just forward of the fuel filler, the other on the front of the engine below the carburettor). As you pull the assembly off the inlet pipe, unhook the throttle link from the carburettor. You do not have to disturb the governor spring(s) - just don't damage them/it. Sometimes, the sealing O-ring stays on the inlet pipe - if it does, pull it off and re-seat it in the carb before re-fitting.

3) Separate the carb from the tank (5 screws). Between the 2 you will fing a gasket and a rubber diaphragm - both included in the repair kit.

4) Re-assemble with the new parts. Make sure the surface of the tank and the base of the carb are CLEAN.

5) When you have it back on the engine, check that the throttle link (the thing you unhooked when you took it off) can move FREELY - no binding at all. If this gets jammed, you will have a runaway engine.

6) If all OK, replace the air filter. Job done!

All of this assumes a recent (primer start) engine. If yours is an auto-choke type (butterfly valve visible when you remove the air flter) let me know. The procedure is similar, but a little more involved.

phil_saunders(a)bigfoot.com

Phil Saunders, September 2012

to much oil

CUTHEGRASS, September 2012

Black smoke: over rich mixture: incorrect carb adjustment or clogged air filter,

Blue smoke: blocked engine breather pipe or at worst Worn engine( top end ): perished valve stem oil seals, worn valves and guides, worn cylinder liner, piston and rings.

Most garden centres have a spares and service department, take it to one and have it inspected, may need a general service :)

e manno, September 2012