fecking mower!

[bewsher500]

really p1issing me off now"!"

mountfield hp474 with cut out bar

was working fine, now starts but cuts out after a second
will only start on full choke
will only start again after a period of pause

have drained fuel replaced, drained carb, drained oil and replaced,

checked fuel, spark, plug is clear, gap is fine, nothing hooked up or interferring with carb and choke settings
micro switch for cut out is open
air filter cleaned, coil seems fine (as it will spark the plug on every start stroke with plug out)

doing my head in!

am guessing it is flooding since it will fire after a rest but it won't stay running even if i catch it and knock the choke off once firing

 

[Eric the Red]

I didn't know fecking needed mowing - I shall have to read the descriptions of mowers more closely next time I buy one - and consider whether I need to start mowing my own fecking preserve. I only have a small patch, but I don't want it to proliferate, albeit that it is very good for feeding the breeding BuggerAlls.
Are you sure you have a proper fecking mower - and not been mis-sold the common or garden lawnmower in its stead - all of which are prone to the condition you describe. More commonly known as 'sulking' having been left in the shed all winter.......

 

[Steve Sykes]

Is it a Briggs and Stratton engine?
mine did the same changed the diaphragm in the carb
works fine now
search you tube how to fit quite easy & just a couple of quid

 

[Eric the Red]

(Check the carb valve...... and the governor spring - these have a habit of unhooking/snapping, so the mower won't autochoke properly)


There you go - ^^^ diaphragm - proper word..... ^^^

 

[bewsher500]

yes, B&S
will have a look thanks
had the carb off but couldn't see anything that had come loose, failed or was stuck

 

[Briar]

Had similar problem with chainsaw a while back. If I remember right it the flexible rubber pipe between fuel tank and carb was beginning to perish and had small hole in it. Hence it would start on choke but fail to run..
May be worth a look...

Briar

 

[Eric the Red]

yes, B&S
will have a look thanks
had the carb off but couldn't see anything that had come loose, failed or was stuck

The diaphragms do give in the end - but easy and cheap to replace. Need to have the whole thing apart - right up your street Ed, surely?!

 

[teyhan1]

Post a picture of your engine showing the carb and I'll probably be able to tell you what to look at

 

[bewsher500]

cant see any fuel leaks on the tank to carb hose

have no problem stripping it, just can't be arsed stripping and rebuilding to find out that some part is dead that I can't see!
what exactly does the diaphragm do?

wouldn't a leak just make it run rich?
would expect a rich mixture to even out on less choke (choke makes it rich surely?)

teyhan it is this one:

http://www.spares4me.co.uk/mountfield_diagrams/M389A.gif

 

[bewsher500]

better pic but it doesnt show the regulator arm which I can't find any details on!

http://www.spares4me.co.uk/mountfieldgraphic2009/A-M150-09.gif

 

[Steve Sykes]

Get my spares from http://www.briggbits.co.uk

 

[bewsher500]

link broken

 

[megsjockey]

Not broken, missing an 's' https://www.briggsbits.co.uk/

 

[Eric the Red]

Money might be on the governor spring then.....

 

[ELMER FUDD]

Also had a similar problem with a chainsaw. After checking everything, concluded it must be the carb so replaced this and problem continued. Changed the plug which wasn't very old and this cured the problem.

 

[bewsher500]

Money might be on the governor spring then.....

Spring looks fine, can't work out what is at the bottom end of the arm
i read that some models gave a fan that pulls the arm against the spring once running to auto adjust carb
cant see if this model has something similar

tried starting it with spring off and arm pulled back....no good

 

[Taff]

Just checking but you have put fresh fuel in, not from last year.

 

[Eric the Red]

Spring looks fine, can't work out what is at the bottom end of the arm
i read that some models gave a fan that pulls the arm against the spring once running to auto adjust carb
cant see if this model has something similar

tried starting it with spring off and arm pulled back....no good

Some B&S engines have two springs that work in counter measure......

 

[bobdabob]

sounds like a perished fuel pipe some way in the fuel line ! doesn't take much of a hole and would be worth while renewing just to strike of your list of probs

 

[Tam the Gun]

Might be worth stripping and cleaning the carb.

Oakys Garage: Carb clean, Pilot Jet clogged, Wont run without Choke... Carbs 101 - YouTube