My Mantis let me down on Wednesday which was annoying to say the least. I hadn’t used it for a couple of months so it had stood with fuel in and when I came to use it, it just wouldn’t start.
After repeated tries and encouraging the machine with some choice Anglo-Saxon phrases, I changed the fuel and checked the air filter. The spark plug was a bit sooty so cleaned that and reset the gap.
Success! It finally started up and it’s now starting perfectly at least, but it now loses power at high revs and cuts out. This is apparently a classic symptom of fuel shortage caused by the carburettor being gummed up.
So my next job will be to check and clean the fuel filter and I’ll try some of the fuel additive that’s supposed to clean and remove deposits from the carburettor. If that doesn’t do it another hefty bill from the garden machinery shop threatens. I’m not one of those clever souls who can take apart engines, fix them and put them back together.
Fuel Life
The manual does warn ā… Fuel deterioration and oxidisation can occur in as little as 30 days and may cause damage to the carburettor and / or fuel systemā And that assumes the fuel was fresh when it was put into the tank. Our garden machinery shop even gives out leaflets warning about petrol going stale.
No Petrol in 1973
I remember my dad storing petrol in jerry cans sometimes for months way back in the 70’s when there were shortages during the oil crisis. And here we are, 40 years later and it won’t keep for a month?
It’s not just the fuel either. Regulations have forced manufacturers to improve fuel efficiency and reduce emissions although I find it hard to believe that the small engines in garden machines make significant difference to CO2 in the world compared to cars and power stations.
These new generation machines are efficient and economical to run when they run but there’s just no tolerance, no leeway at all. You must make sure the oil is changed regularly and at the correct level. You must make sure the fuel is fresh or else there will be problems.
Having said that, I now add a fuel stabiliser to the can as I bring it home which is supposed to give the fuel a longer storage life. I’m using fuel-fit by Briggs & Stratton
It’s not just the Honda engine in the Mantis Tiller, the same applies to my petrol strimmer and petrol lawnmower. I suppose it’s across the board now with modern garden machinery, whatever the make.
My old Merry Tiller is a different beast. Leave fuel over winter and it coughs a bit as it starts. Forget to top up the oil and it runs as well despite there being half the oil it should have. Noisy and inefficient it may be but it starts and runs.
Maybe it’s just me, but surely progress should have given us more reliable machines, not these highly-strung, sensitive motors that only run if everything is perfect?
Take a trip to your local Halfords and get yourself a can of carb cleaner.
It is the dogs danglers for sorting out such fuel problems and works out a lot cheaper than the repair man.
@Andy: Thanks Andy – I’ve got some Redex injector cleaner fuel additive from Halfords. Is that the correct stuff? I’m not much cop with machinery š
Nooooooo John. That only works on injectors. Carburetor cleaner comes in an aerosol. Remove the air filter and give it a squirt straight into the carb. Leave it for a few mins then start it up. Give it a short couple of squirts with the engine running. It will clean the jets out and remove any goo from inside the carb. Stick the air filter back on and job done.
The shop would do exactly the same and then charge you many beer tokens for the privilege.
@Andy: Thanks again, Andy. I’ve got a feeling you’ve saved me a lot of beer tokens in the future!
Always feel free to contact me about mechanicals.If there is a cheap simple alternative to taking something to the shop I probably know it.
Hi John.
Re your problems with fuel, are you using supermarket fuel?
I have been told that it does not have the same additive’s as Shell, Bp,ect.
I use Bp and never have any trouble with my machines.
@Eddie: Hi Eddie, I usually get my fuel from a little local garage. It’s a Murco station. Very expensive but 4 miles closer than town. No BP around here that I know of and the nearest Shell is 15 miles away in Porthmadog.
The joys of living in the sticks!
For the car we tend to use Morrisons or sometimes Tesco if we’re going to Bangor.
Thanks for the mention John.
It should not make any difference where you but your petrol from. They do put a couple of goodies extra in the premium petrol but that should not make any difference to a small 4 stroke. Just remember that with a 2 stroke it is very important to get the mixture spot on. too much oil will impede combustion and too little will not give enough lubrication to the engine.