Lawnmower Carburettor Ethanol ?

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Lawnmower Carburettor Ethanol ?

Post by svenedin »

My friend was having problems with his Honda Izzy lawnmower. It would start but cut out after a few seconds.

I took the carburettor to pieces and I found lots of nasty aluminium corrosion. I cleaned everything up including removing the main jet, float and needle valve. I managed to tear a gasket but I had gasket paper and made a new one.

All running beautifully now.

I assume that this is the effect of leaving ethanol containing fuel in the lawnmower over the Winter. I have exactly the same lawnmower but I use a fuel stabiliser and I have never had an issue in 14 years of owning that lawnmower. My friend's lawnmower on the other hand is 3 years old.......

I post this as it may have some vague relevance to our cars which also have aluminium alloy carburettors and are unused for the Winter or longer. With garden equipment you can drain the fuel tank but you cannot easily drain the float bowl. Same with our cars.

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1969 1098cc Convertible “Xavier” which I have owned since 1989.

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Re: Lawnmower Carburettor Ethanol ?

Post by Blaketon »

Years ago, in the days of four star, you could start a car, that had been stood for a while and it was fine (I never just left them for months on end anyway). Back in 2017, I tried to start my Midget 1500 after a biggish engine job and it just went futt futt futt and would not pick up. I pumped the fuel out, with the electric fuel pump and put in some fresh (Super unleaded) and all was well. Mark, from Jigsaw Racing (Triumph specialists), advised that modern petrol is unstable and to always use something like Millers VSPE, which I have ever since, even in the petrol driven garden machines.
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Re: Lawnmower Carburettor Ethanol ?

Post by philthehill »

My mower fitted with a Honda OHC engine started 2nd pull after standing all winter in the shed. The carb is fitted with a choke which helps.
Most Honda engines fitted to lawn mowers have a float chamber drain facility or the ability to easily remove the float chamber to drain.
After a summer of mowing I drain the fuel in the tank, drain the float chamber and give the carb a good spray over with WD 40 or similar even inside the float chamber which helps fight corrosion.
I have not yet felt the need to buy any special mower engine ethanol free petrol. If needs be and I have to replace the carb the carbs are readily available from 'e' bay and cheaper than 5 litre of special fuel.
I had to replace the carb on my Honda engine powered generator (basically the same engine as the mower) and I fitted a very cheap copy and it now runs better than it has ever done. :D
My mower has to work and is abused but the good old Honda engine sees me through.
The biggest problem I find is that the steel deck eventually rots away so I purchased a good S/H alloy decked 16" Mountfield mower and fitted the 5hp Honda engine to it from the rotten steel decked 20" Mountfield so plenty of power to push through field grass. The Honda engine has seen at least 26 seasons of grass cutting without fault. :tu1:

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Re: Lawnmower Carburettor Ethanol ?

Post by alanworland »

If the Morris is not to be used for a while I have always allowed the engine to use what's in the float chamber by turning off the fuel pump using it's isolation switch, surprising how long it can run!

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Re: Lawnmower Carburettor Ethanol ?

Post by olonas »

Remove the Ethanol, I do. Not really much of a hassle for the amount of fuel a lawnmower's, or other Petrol powered garden tool, uses.
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