Project Scythe : Success

[Following on from this post]

Blimey that was quick! I only ordered the replacement parts on Friday morning and they arrived the next day (yesterday). I was too busy then to try anything out so today was my first chance to have a play.

First thing was to remove the whole tank and carburettor assembly. This wasn't too tricky - the hardest bit was removing the throttle cable.

The old carburettor still attached to fuel tank

Next up was to remove the carburettor from the tank. This is a simple case of undoing the 5 screws holding it on. Once it was off I gave the tank a good clean to remove all the crud that had built up around the mount points.

The old and the new

Although the new carburettor came pretty much assembled, there were still a few screens and springs to put in position. Once these were in place, it was a case of placing the diaphragm and gasket on the tank and then positioning the new carburettor on top. After doing up the screws the job was done.

New carburettor on the cleaned up tank

Then came the tricky bit of putting the tank/carb back on the mower. Again the throttle cable tried to be awkward but after a bit of negotiation it was back in place and all tightened up. I then replaced the spark plug. However I left it unplugged as a precaution.

The newly assembled carburettor and tank in situ

Then it was ready for testing. I moved the mower outside and onto a piece of lawn. I primed the carb three times with the new bulb. It seemed to work perfectly, I could hear the fuel squirting up! Then I pulled on the started cord.
Nothing.
Again. Nothing.
Feeling slightly deflated I realised that I was no further on than I was before. So I walked around the front of the mower and ... hah! I'd forgotten to reconnect the spark plug! I quickly plugged it in and pulled again on the cord. Still nothing. I re-primed the carb and then pulled on the cord once more.
Success! With a puff of white smoke the engine burst into life for the first time in over a year!

Success! The mower is working!

After that it was a case of working out how the mower worked. Then off to mow the lawns in record time. So much easier when you don't have to mess about with power leads.

The next things I need to do are get the blades sharpened and replace the air filter with the one I bought.

But Project Scythe has been a complete success and I'm hugely pleased with how it's turned out.

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