Project Scythe

Our electric lawnmower has given up the ghost. It started producing smoke from areas where it shouldn't - namely the motor! I can still smell the electric burning smell now.

The electric mower was getting to be a bit of a pain anyway, mostly because we have two lawn areas at the front of the house, an L-shaped lawn round two sides and a triangular lawn where the greenhouse is. So when we mow the lawns there is a lot of plugging and unplugging of electric extension cables to be done. A petrol mower would solve this particular problem. However, petrol mowers are much more expensive than their electric equivalents.

As luck would have it, Mrs. Matt's sister has donated her old petrol mower which fails to start. I have a few weeks to get it working before the grass gets over our heads.

Welcome to Project Scythe!

Project Scythe - the mean machine

Now, there is one slight problem with this kind of project - I know next to nothing about engines. But why let that stop me.
First off was a quick bit of cleaning around the engine, removing bits of grass that were there from the last time it worked, over a year ago.

10 year old lawnmower with 3.5hp Briggs and Stratton engine

Then the investigative work began. It's a Briggs and Stratton engine, 3.5hp. According to the engine plate on the front, it's Model 9D902, Type 2006 E1, Code 98072954.
I've since learned that the Code is the date when the engine was made, in the format YYMMDDxx. So this engine was made on 29th July 1998 - almost exactly 10 years ago.
All this information is essential when ordering replacement parts as B&S make so many different engines.

Once I'd got some petrol and fashioned a funnel out of an old pop bottle, it was time to put some fuel in the tank and see what happened. Once the fuel was in, it needs to be moved into the carburettor, ready to go into the cylinder for ignition.
The thing that moves this initial bit of petrol is the primer bulb, a sort of rubber suction device. The little label next to it says to press it three times. Well after the first press it never came out again. I tried pressing it in a few more times to see if it would pop out but no. Anyway, I thought I'd try and turn the engine over and see what happened. It seemed to turn over ok, but not do a lot else.

The primer bulb refuses to pop out once pushed

So the initial diagnosis it that there's a problem with the primer bulb or some of the jets and tubes feeding it. I tried removing the bulb and then the carburettor but had no luck with either. I did all this after unplugging the spark plug just in case of a discharge while I'm messing with the fuel feeds - I read that somewhere. I think. So I decided to put things back together and then retreated to the PC and did some searching.
I found one site which gives details of removing a very similar carburettor. You need to remove the carb and fuel tank as one unit first, then remove the carb from the tank. It also details how to remove the primer bulb!
After looking and reading about all the bits that could be wrong in there, I decided to buy a whole new carburettor with all the gubbings (including the primer bulb assembly). While I was ordering I also picked out a new spark plug, air filter and some fuel conditioner (apparently petrol goes old and can gunk up the workings when left for a while). The whole order has come to £28.48 at the moment. Plus the £3 I've spent on petrol.

So that's where Project Scythe is at the moment: Awaiting parts.

UPDATE: This is the next page of Project Scythe