Lawnmower

[michaelpeterwilcock]

I have a fairly old M3 Mountfield Lawn Mower. It has served me well but last year it began to have a problem. It always starts well from cold but when hot refuses to start. I contacted a repairer who, without seeing the mower, claimed it was a problem with the cylinder head and was not worth repairing. Has anyone any idea what may be causing this?

 

[Burnerman]

It makes you wonder what sort of problem the cylinder head could have to cause poor hot starting......
The motor is running probably slightly rich, so check the air cleaner and don't over oil it ( foam type).
Post back with a picture of the carb, if you will......especially if the fuel tank is below it!
John

 

[michaelpeterwilcock]

Thanks for the reply. I have taken a photo of the carburettor but I am not sure that I can work out how you see it. I hope this works.

The carburettor is below the fuel tank. I also checked the plug which seemed OK.[/img] View media item 91801

 

[Burnerman]

Yep, that's fine.....if you feel happy, take the air cleaner element out, so you can see down the throat of the carburettor. Is the air cleaner paper element clean?
Pressing the primer bulb shoots a tiny spurt of air into the float chamber which in turn causes a drop of raw fuel to shoot out of the main jet tube, visible in the carb throat. See that it's doing this?
Next, I find that these engines don't mind a prime when they are hot either.....give it a bash but don't overdo the prime!
Start the engine on full throttle always, and don't expect a particularly smooth tick over......I'd also pop a new plug in at the same time.
John

 

[Mursal]

Find it fascinating how people can diagnose problems over the phone to the point where "its not worth fixing"

Local white goods shop started selling Husqvarna and Jonsered and I recently phoned with the part number for a vacuum pipe need for a little saw. Well, I was informed that the part number was no good to them, and they didn't expect the part to be available. All in one breath, without even looking up the part.
Our dog would have more interest ....................

Having said that they are selling new saws cheaper than they were 20 years ago, €220 for a 36CC Husky.

Sorry its not relevant to your lawnmower ...............

 

[Burnerman]

Couldn't agree more!
At least with this mower, it's a Briggs motor so all parts are available.
It's a side valve too.....so the only thing that could go wrong with the cylinder head are the plug threads and the head gasket.
Clearly the 'diagnostic specialist ' couldn't be bothered to help.
John

 

[michaelpeterwilcock]

Thanks for the help guys. Since going through a few things such as checking the filter and the spark plug my lawnmower is now performing well.