Rotavator won't start

Habbakuk

Thank for all of your replies. I'm going to have another crack at it today and try some suggestions above.

Habbakuk

I've cleaned the carb and put tried putting a litte petrol into the engine and also tried a mix with less oil and still it won't start. Not sure what to try next. There is a spark in the spark plug when I take it out and pull the starter and earth it.

cyclonebri1

The old trick was to heat the plug up over a gas ring, screw back in and PULL as quick as possible..

To be honest if you do this vigorously, and you have a spark, (timing fixed on these simple engines), then it will start unless there is a fuel/carb issue;)

pogg000

There is a spark in the spark plug when I take it out and pull the starter and earth it.

even though the spark plug is sparking when tested like that does not mean it will work when under compresion as the voltage required to fire under compresion is much higher!

Have you tried it with a new plug? old oil can bury itself into the insulator and stop it from firing.

Stooby2

Sorry if this is stating the bleeding obvious, but has it got a choke and are you using it?

The other thing to try would be to heat the engine by using a hot air gun on the fins.

cyclonebri1

Given the conditions today I wouldn't worry too much about getting the rotavator going.

As suggested, several, you need to get a new plug.

There was another dodge we used to check if a plug was failing under compression. Care needs to be taken, but if you screw the plug in by hand, then wind it a turn out then try to start it. The compression is reduced and the engine my fire.
Switch it off if it does, the plug won't take long to blow out.
If you get a result, you have your answer.;)

Habbakuk

I'm beginning to think that it's a fuel problem. I've taken the spark plug out and pulled the starting cord. I can see the piston moving but there's no smell of petrol at all. Surely, there should be?

cyclonebri1

Habbakuk wrote: »

I'm beginning to think that it's a fuel problem. I've taken the spark plug out and pulled the starting cord. I can see the piston moving but there's no smell of petrol at all. Surely, there should be?

Yes their should be on a car engine but the volume of a single 2stroke engine means you may not detect it.

Ok, again, heres another trick. Not recommended by the HSE but given that it's a rotovator and we do this with car engines, try this;

Get someone to crank the pull rope. You hold the plug and lead in a pair of insulated pliers or rubber gloves and touch it just outside the plug hole, bring it right up to the hole with each pull.

You should get a mild "puff" as the uncompressed fuel blows off.

Mate with a low lighter is another 1, works on 2 stroke but not 4.

If you have fuel you should get some form of ignition.

We are getting to the last resort options here and I have to repeat, before you try that, have you put a new plug in?

tony6403

Basic stuff here : has your rotovator got a fuel tap and is it switched on ?

Stooby2

Similar to the above - is fuel getting through the tap? It's not uncommon for them to get blocked.