Fixing a petrol mower

[soprano]

Ok - I have two lawnmowers, both petrol, neither will start. Both are four strokes.

I haven't looked at the second yet. The first one has been abused, left outside in the rain, it was run for quite a long time on a mixture of petrol and two stroke, with two stroke instead of four stroke in the mower in the mistaken belief it was a two stroke mower. The blade has probably been ploughed into tree stumps and drain covers. Unsurprisingly it won't start. It was only a cheap mower to start with and so is probably uneconomic to repair. Rather than simply throw it away I thought I would try and learn a thing or two about fixing an engine.

At the moment I don't know much about engines. So far I have done the following:

1. Emptied the petrol tank of the wrong fuel mix, as well as the filter and pipes to the carb and refilled.
2. Changed the oil for the correct oil
3. Cleaned out the carburettor, but only with tissue - I think you can get carb cleaner?
4. Checked that the fly wheel pin is still in one piece
5. Changed the spark plug and checked that it is sparking which it is

It still won't start, and doesnt sound like it wants to at all. It doesnt have the usual push button to prime the engine, it has a red lever which opens/cuts fuel to the carb. What shall I check next - any ideas?

What will running the engine on two stroke as opposed to four have done to it?

[spikeyhead]

Is the petrol getting to the plug? you'll see it wet after a few pulls and it not showing any sign of starting. If not then the carb is blocked, probably with good old carb gunge. Alternatively, a lot of mower carbs have a diaphram in that is very prone to splitting.

[soprano]

Would the top of the plug actually be wet - I dont think it is so perhaps that is the problem. The fuel is def getting as far as the carb.

Would the use of two stroke over a long period have adversely affected the engine? I read somewhere that it may coat the internals in soot/black gunk

[mondeoman]

Has it got a choke?

[thinfourth2]

Pour a tiny bit of fuel into the air inlet

Then try to start it

[soprano]

It does have a choke - I will try pouring a bit of fuel in the air inlet - I have also read that soaking the air filter (sponge) in fuel is something to try - I presume these do the same thing>

[mondeoman]

Or try some Easi-Start spray?

[shtu]

Odds are that either the fuel supply to, or the carb itself is blocked up, or the diaphragm has failed, which are both easy fixes if you are fairly handy with tools - they're pretty simple carbs.

As mentioned, a squirt of easy-start down the inlet is the best way to tell - if it fires on that, inspect the carb.

[soprano]

Well I managed to get it going this morning so thanks for all your help! Couldn't have done it without

Cheers all

[soprano]

And fixed a second mower over the weekend - the gift that keeps on giving

[mondeoman]

[j4ckos mate]

Ive seen two for a tenner on ebay,

i like messing with my car, but only the basic stuff, i think i might buy them and see if i can get them working again

[Tampon]

j4ckos mate said:

Ive seen two for a tenner on ebay,

i like messing with my car, but only the basic stuff, i think i might buy them and see if i can get them working again

Do it I made over £4k last spring and summer after starting do this on the £100 business challenge thread on here. Ended up with a decent tool set and loads of equipment.

Best tip, buy carb cleaner. 9 times out of ten I could get a none runner working by squirting some down the air intake and cranking it over, this was enough to fire it up and draw fuel through a slightly dirty carb.

Don;t touch anything with rusty decks, Hayters have the same Briggs engines as cheap Sovereigns mowers so look at expensive non runners as they are as easy to fix as cheap ones.

[shouldbworking]

Rescued 2 so far in the past three years. Once with a squiry of easy start, once I had to go extreme and clean the spark plug.