Lawnmower (petrol) power dropping off

grumpycrab

Hi - we've a cheap and cheerful petrol 'mower in its 3rd (or 4th) season and the engine (Briggd&Stratton) has a couple of problems.
1. has cut-out a couple of times recently (not fuel related)
2. is very difficult to start when warm
3. has started to lose power

So, service time. I'll change the spark plug and have a look at the air filter (not sure about the latter). Is there anything else I can do?

spacey2012

I take it you have not left any fuel in it from last year as you say not fuel related.

grumpycrab

spacey2012 wrote: »

I take it you have not left any fuel in it from last year as you say not fuel related.

Ah, no. I say I believe its not fuel related because the couple of times it has stopped on me (suddenly) there was no fuel shortage - it normally chug-chugs if its running out of fuel.
BUT I don't drain the fuel between seasons.

DaftyDuck

It may not be running out of fuel, but old fuel from last year evaporates, leaving a poor-burning mixture ... certainly does cause loss of power in my mower. I mix up last year's fuel with new stuff to get rid of it... or use it in SMALL quantities to light bonfires. It's not that unvolatile...

grumpycrab

Although I don't drain between seasons I guess by now the new fuel (a moth or two old) I expect is ok. How important is the air filter (and should I clean it?).

lardlikesdogs

have you cleaned the spark arrestor out (where the fumes comes out) if this is clogged up it will struggle when warm, There is a screw or bolt that allows you clean the mesh filter, Its this that is causing the engine to pack in it happened on my petrol leaf blower after a few minutes use it would stop and not start again I cleaned out the mesh filter that was clogged up with carbon and bingo the engine could breath again.