Lawnflite 504 cutting out

[Steve2018 3]

Got to the end of my cutting day and my Lawnflite 504 cut out. Tried starting it and it would idle then die when I apply throttle. 

 

Took the filter off and started it and when I applied throttle it would make like misty puffs of Im guessing fuel vapour then die and inside the carb walls they are  wet with fuel 

 

 

 

Does it sound like I have sucked dirt into the carb and need to strip / rebuild it? 

 

I noticed when it was working the smoke from the exhaust was a little bluey looking at max throttle 

 

Thanks 

[Wristpin 400]

Pull the oil dip stick and give it a sniff. If it smells of petrol its possible that the carb is flooding and raising the oil level in the sump. Another quick test is to remove the yellow ?? kill wire from the throttle pate which will totally isolate the engine from the influence of the safety switches etc and will determine whether it is an engine problem or a systems issue but be aware that the engine will not stop on the key with that wire disconnected.

[meadowfield 1,900]

does it run better and longer with the choke on, that's usually indicative of crap in the carb.

 

Another favourite on briggs and kohler carbs is the float needle sticking so it might not be pulling enough or any fuel through.

[Steve2018 3]

Thanks will try these ideas on the weekend. 

 

Im sure it bogs down and cuts out when on choke 

 

Thanks 

[Steve2018 3]

Dipstick smells ok and it also still cuts out on full throttle + choke. 

 

Going to pull the carb off and clean it out maybe i should use a genuine briggs fuel filter instead of a universal one...

 

Thanks 

[Wristpin 400]

If your universal filter is designed for an application with a fuel pump there is a possibility that it is not letting enough fuel through from a gravity tank.

If going genuine Briggs you need the red 298090S and not the white one which is for pumped applications.

[Steve2018 3]

It was for a non fuel pump engine but maybe the filtration of it was poor... 

 

Still haven't had time to strip it lol

 

I thought it was supposed to be red as well. I was going to order a 298090S filter on Amazon but it is White 

 

Briggs & Stratton 992350 298090S Fuel Filter https://www.amazon.co.uk/dp/B016BXY078/ref=cm_sw_r_cp_apa_i_4J2UCbWMXY6W9

Edited April 20, 2019 by Steve2018

[Steve2018 3]

Ok took carb apart and looked ok and put back together and still wouldn't  run. Took the spark plug out (wish I did this first) and it was covered in black soot,  cleaned it and it started and ran :-).

 

Stupidly  I thought I will try and adjust the carb settings as it was a little roughish sounding... Wish I just left it alone...  Turned it a little and now not running again seems to be alot of fuel coming through the carb when trying to start and fuel vapour popping out the carb inlet. 

 

Can the adjustment needles become worn? 

 

Thanks 

[Wristpin 400]

The needle can become worn  - more often damaged by over tightening , but that should be visually obvious. 

If all else fails it may be worth checking the valve clearances or even a loose valve seat - usually the inlet.  

 

[Steve2018 3]

Is it as easy as checking valve clearance on a classic mini with feeler gauges? 

 

Purchased a running Lawnflite 504 mower without cutting deck for £50 so should be sorted soon :-) 

[Wristpin 400]

Checking is relatively simple but if they need adjusting it gets more complicated as reduced clearances are increased by grinding metal from the end of the valve stems . The worst case of a loose valve seat probably requires the rear body work to be removed to give decent access.

[Steve2018 3]

Sorted :-) 

 

The engine with the £50 lawnflite had a running problem (only ran on choke)  sorted that by cleaning all the blockages out the carb. 

 

Swapped the cutting gear over from the non runner and its going great. I even have all 6 speeds to select from instead of just speed 5 or 6 :-) 

 

The engine must be newer as it uses the two piece carb with only one adjuster needle instead of the one piece  carb with two needles and it runs so much smoother and easier to setup I think.

 

 

The old engine was puffing blue smoke at high revs this ones nice and smooth :-) 

 

Still going to look at getting the non runner going again but good to have two of the same mowers for spares