Lawnmower Woes

[gman76]

Flymo Quicksilver 46sd with Briggs and Stratton 450 series 4 stroke engine.
A year or two ago the above mower was hunting and puffing black smoke, I replaced the diaphragm under the carb and it was running sweetly. It rested up last winter (nothing drained down), I had a bit of a job getting it started this spring, but it ran well once going.

On it's second outing, I can't get it started at all. There is fuel in the tank, there is a spark and the air filter is ok, there is no smoke coming from the exhaust, but it does smell of burnt fuel. There are no signs of it firing at all, not even a chug.

I wondered if the diaphragm may be shot again, but the priming bulb shoots fuel straight in, so I would expect it to fire then die if this was the issue.

Anyone have any suggestions?

 

[Burnerman]

There's certainly nothing wrong with your logic, regarding the fuel primer!
Before you take the carb off again, is there any chance of the engine being flooded, do you think? If this could be the case, the plug may be wet with fuel, so crank the engine over a few times just to clear it.
Its unlikely for the plug to fail, but always try a spare one, just in case.
If no joy there, its carb off the tank again, and this time check the filter at the bottom of the dip pipe (nylon gauze) for particles of grot.
Genuine Briggs diaphragms generally last more than a year but if its distorted or 'puckered' then treat it to a new one.
John

 

[gman76]

Hi john, thanks for taking the time to respond.
The diaphragm was indeed a genuine one. I don't think it was flooded, certainly not to begin with - I pulled the thing until my arm nearly popped out of its socket!
The plug did look a bit sooty and damp, I also thought the gap looked a little big too, but I didn't have my feeler gauges with me (its my MIL's mower).
I will take another look next weekend and let you know how it goes.
Thanks again.

 

[Burnerman]

I wouldn't worry too much about the plug gap - it's hardly critical on these!
Take a spare plug with you if you can.....they don't fail that often, but may spark in open air, yet fail under compression.
If you think you may have flooded the thing ( fuel smell in the exhaust) try starting without using the primer bulb.
John

 

[Mursal]

Better than the gym and cheaper ..............
And you know she'll appreciate the effort
They can be very temperamental ...........

 

[Peter.N.]

I have a similar problem most years with seldom used engines. Take the plug out and make sure its dry,if not dry it and the squirt some easy start into the plug hole and refit the plug. If you still have no go try squirting easy start into the air intake.

Peter

 

[gman76]

Just a quick follow up on this. Finally managed to get round to looking at this again. Popped a new plug in and she roared into life in a huge cloud of smoke on the first pull.

Many thanks for your assistance.

 

[Burnerman]

Nice one!
With most mowers, only tip them back on the handles to clean or clear......tipping them on their side invites trouble.
John