Lawnmower - low power

[dkh]

Hi, not really sure if this is diy - but i cant find a more suitable group

My 1 year old Rover electric start power drive petrol mower developed a twisted 'chute guard' which prevented me from pulling the mower backwards - it was catcing on the ground.

I put the mower on its side on a bench and removed the guard, straghtened it with a hammer and then put it back - no problem there.

However ever since the mower a) first would not start and then b) started but runs underpower (spluttering, changing speed, sounding like it might stall but not stalling.)

A friend looked at it - we changed the spark plug, drained the carb, and cleaned the jets - but its no better at all.

Has placing the mower on its side put some setting off or drained oil into the engine which is clogging it ?

any advice appreciated as to what I should try next before I have to leave it in for a service.

[Geoff Norfolk]

It may sound obvious but have you checked the air filter................. it could be saturated with oil if you had the machine on its side. Alternatively, have you checked the exhaust isn't blocked with oil?

Geoff

backwards -

[dkh]

"Geoff Norfolk" wrote in news:gz7ie.9366$ [e-mail]:

Nope - air filter seems ok - had a little petrol on it but it dried out....

[PJ]

Is the filter on the tube in petrol tank leading to the carb. blocked?

[dkh]

PJ wrote in news: [e-mail]:

Dunno - but its on my list to check tomorrow...

cheers

[bigcat]

backwards -

straghtened

If it shifts up and down in speed cyclicly thats a classic sign of a mix thats too thin. But I dont see how that would result from turning it over. Mystery.

NT

[dkh]

[e-mail] wrote in news:1116288835.462048.106530 @z14g2000cwz.googlegroups.com:

Yep, thats a pretty good description of what im seeing - however the max revs of the cycle still is not 'full tilt'.

When you say mix thats too thin - what does that equate to in a petrol mower (i.e. its not a 2 stroke mixture)

-- dkh

[Dave Liquorice]

Hunting is normally too rich, more fuel than is required. My B&S started doing this last year. Took the carb and tank off couldn't find anything obvious, reassembled and it's been fine since. Must have been a stray bit of gunk.

[usenet]

Too little petrol in the petrol air mixture being fed into the cylinder.

'Hunting' is the classic symptom you get just before you run out of petrol.

There is petrol in the petrol tank is there? :-)

Other than that the most likely thing I can think of other than the obvious things suggested so far is some dirt in a carburretor jet which is preventing enough petrol being sucked in.

Alternatively it *could* be that you've cleaned something out to such an extent that it's now running weak and the carburretor needs adjusting.

[Bob Mannix]

backwards -

Lawnmowers often have (or used to have) a crude governor which is a flap of metal actuated by the draft from the flywheel against a spring pulling the other way, which shuts down the carb a bit when it over revs and vice-versa when it under revs. Check whether it has such a thing and whther it is stuck or the spring has come off. A possibility rather than a probability, but worth a look.

[usenet]

Hmmm, yes an engine will 'hunt' when too rich but it's much more regular and shorter in period than the hunting you get when it's running too weak.

[PJ]

If it is a Briggs and Stratton engine, then one bolt will usually remove the petrol tank which has the carburettor attached which pulls off the engine manifold.

Five screws connect the carb. to the tank. There is usually two filters. One removable one on a thick pipe and one fixed on a thin pipe. Clean these with a toothbrush, empty the petrol, clean the gauze in the tank with petrol where the thick pipe fits and reassemble.

Anything else and I have not got a clue.

[nick smith]

If the petrol filler cap breather hole gets blocked, this can / will restrict air into the tank and petrol out of it - fairly unlikely though as they all seem to be a fairly loose / leaky fit.

Nick

[bigcat]

backwards -

straghtened

I think the logical thing is to post to the stationary engines group, we seem a bit short on knowing what it is here. Rec.stationary.engines or something. uk.rec.engines.stationery

Hmm, dont think I've seen many stationery engines before: would they be the ons that print newspapers?

NT

[The Natural Philosopher]

Running in bursts with gaps between is lean.

Running with lots of smoke, down on power, and burping and farting is too rich.

Mind you these things are reguklated RPM wise anyway, so it may be a problem there.

clean all fileres and the carburettor, and try again.

[Bob Mannix]

Yeah, come to think of it, there are people who fit that description :o)

[dkh]

"Bob Mannix" wrote in news:d6ciqo$jgr$ [e-mail]:

Yes it does have one of these - i spotted it when i took the cover off for a quick look. I did not know what i was looking for so i put the cover back on :-)

[Bob Mannix]

In that case make sure it wasn't trapped when the cover went back on!

[Kaiser]

Try a new spark plug. If the engine has been on it's side the plug could have got oiled up and as a result is probably on its way out.

[dkh]

"Kaiser" wrote in news:428a472d$0$294$ [e-mail]:

Put a brand new plug in last night - no difference unfortunately....