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John B
John B, Small Engine Technician
Category: Small Engine
Satisfied Customers: 3
Experience:  20 years working with small engines and related equipment.
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My Lawnflite 920 is getting on a bit now but has never been

Customer Question

My Lawnflite 920 is getting on a bit now but has never been problematic starting until yesterday. It didn't sound right when turning it over so I thought it might have flooded so took off the front body housing and then set to work to take off the Briggs & Stratton power unit cover to get at the spark plug more easily. This meant I had to remove the oil dip stick too and, to my surprise, a torrent of oil and fuel spewed out of the dipstick housing which told me that the card had been leaking by into the combustion chamber and then into the sump. I've emptied most of the sump out now but am wondering how big a job it will be to fix this and it it's just an gasket or 'o' ring which might have gone west on me. It's been a good machine but I'm wondering if I'll have damaged it trying to start it and if it's worth the bother?
Submitted: 3 years ago.
Category: Small Engine
Expert:  John B replied 3 years ago.

John B :

Hello, and thanks for the question. If you haven't run the engine in this state, then there should be nothing to be concerned about. The first thing you will need to address is the carb issue, the needle and seat will need to be replaced to prevent further flooding issues, and then you will want to drain the crankcase completely to get the gas/oil mixture out. Fill with fresh oil, run for no longer than a couple of minutes, and then drain oil again and replace with fresh oil. It is advisable to do this a couple of times, only running for a few minutes each time, until the crankcase is flushed of all fuel.

John B :

Also, before starting, be sure it is not hydrolocked. You should pull the spark plug out and turn engine over with ignition coil kill wire securely grounded with a jumper wire to the chassis/engine. You need to be extremely certain that the coil is grounded to prevent a possible spark causing an engine fire. If you already have the shroud off, you may want to just remove the coil while performing this step for extra precautionary measures.

John B :

You then can re-install the coil and set the gap to the recommended .010" using a feeler gauge, or the old school trick of using the thin cardboard of a cigarette pack will get you by in a pinch, if you do not have feeler gauges.

John B :

If anything I have mentioned requires any further explanation, please advise and I will do my best to be of assistance. Thanks!

Customer:

Thanks for that - it confirms my thoughts! It's not hydro-locked as I've turned it over already by hand. Time is not on my side unfortunately and there aren't too many Lawnflite agents in Devon, so do you think I should just bite the bullet and ring a mobile engineer to come and sort this rather than tacking it myself? My experience with carbs over the years has been variable, so it might be best to use an expert!

John B :

It is entirely up to you, but not entirely difficult if you have the necessary tools. You will need a 1/4" tap and a 1/4" hex head bolt approx. 3/4" long or longer, and basic hand tools. The tap is used to thread the brass seat and then you pull it out with the bolt. If you wish to tackle this on your own, I will go into further detail so you have a step by step process to follow.

Customer:

I've sorted it by putting an in-line fuel cut-off valve and replacing the oil after flushing and it fired first time and ran a treat! Thanks anyway, Dick

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Customer: replied 3 years ago.

I suspect this is a common problem with most ride-on mowers having spoken to my neighbour - he says he would now always fit an in-line fuel cut-off valve to stop a carb leaking by as it happened to him with a brand new machine last year just out of warranty!

Expert:  John B replied 3 years ago.
Hi, sorry for the delay, been having internet troubles today. I am glad you got it up and running, but the fuel shut off is not to be considered any more than a preventative measure, if the float isn't seating properly it is still possible for the engine to flood while running and run excessively rich. I would still recommend replacing the needle and seat at the earliest convenience to prevent future troubles.