OutdoorKing Repair Forum Forums Finding and Swapping Idle Chatter Fuel Mix Ratio. Confusion.

Hi,

Sorry for the odd question, I'm just a little confused with my brushcutters requirements for fuel ratio. The manual states;

Motor Fuel: Mix at 40:1 Only. For example, for 1L of unleaded petrol add 40ml of 2 stroke oil. For 5 Litres of unleaded petrol add 125ml 2stroke oil.

Why 125ml for 5L if 1L needs 40ml? Shouldn't it be 40ml x 5L = 200ml ?

Someone in marketing has probably forgotten to update the manual properly when the finance department said that the engines are lasting too long haha

In all seriousness, what sort of engine - if its a relatively cheap one, run 25:1 (200ml/5l) of good quality oil

It seems to be a misprint. As 1L / 40 = .025L (25 ml) which would be US 3.2 oz to one US gallon. If 40ml is used per 1L then the mix would be 25:1 (1L / 25 = .040L (40 ml)) or at least that is how my calculator figures it.

Of course I don't fool with exact mix ratios when mixing my fuel as I use a multi mix oil that is designed to be use in 16:1 to 50:1 engines so I just mix in one gallon batches per package. Of course I rinse the package back into the fuel container to get all the oil out. But we do still have fuel oils that are require to mixed by exact ratios.

It seems to be a misprint. As 1L / 40 = .025L (25 ml) which would be US 3.2 oz to one US gallon. If 40ml is used per 1L then the mix would be 25:1 (1L / 25 = .040L (40 ml)) or at least that is how my calculator figures it.

Of course I don't fool with exact mix ratios when mixing my fuel as I use a multi mix oil that is designed to be use in 16:1 to 50:1 engines so I just mix in one gallon batches per package. Of course I rinse the package back into the fuel container to get all the oil out. But we do still have fuel oils that are require to mixed by exact ratios.

Until last year the packages were 3.2 oz but the last batch came in at 2.66 oz which is a 50:1 when calculated. This is synthetic oil so they are just using a better oil now. And I have seen Amsoil synthetic oils being use at 100:1 mix ratio.

Hi AVB, Tyler and Widget,

as someone who makes 1 litre at a time of 25:1 mix for my Mitsubishi TU-26 line trimmer and Victa mowers, it is 40ml of the anti engine destroying nectar to make that mix up.

125ml sounds about right for five litres of 40:1.

Thanks guys. I thought it may have been a typo. I have a Ferrex brushcutter (from Aldi). I know it's probably not the best, but it was brand new $50. Want to try and keep it as long as possible. Heavy thing it is too lol. I made some 2stroke up (Valvoline oil) + 91. Seemed to go ok.

Impossible to go wrong on that deal. It's a matter of luck at Aldi what you get at the right time.

They're selling their bargain synthetic two stroke again.

Hi Widget,

I would still run 25:1 fuel mix in it, they are just being good environmentally minded at the sake of the engine life.

My Rover blower was recommended at 40:1, once the small bottle of synthetic was used up I switched to 25:1 same as I have run in my green Ryobi Lawn Hornet for 30 years. Still running it with the original Tillotson carb which has never missed a beat.

Manufactures have switch from life of the equipment owner to lifetime the equipment mode. With all the plastic used on today's equipment it makes some sense. Plus they cant make a profit be keeping old equipment die and forms sitting idle the biggest part of the time. Having old part just sitting in warehouses still cost money every year to store them.

On top that there have been a lot of improvements over the last years. Cylinder coating have changed. Even the metal formulas have changed. All this affects the equipment lifetime and performance.

With the creation of synthetic oils, we are cutting equipment pollution. Here in the US going from 16:1 to 50:1 has had a noticeable. Our equipment are no longer foggers. Now if we can only cut out a lot the other pollution sources like all the jet planes and automobile. Both after our 9/11 and the first lock downs for Covid-19 there was visible improvement in the air quality around here. Our skies became dark blue again but of course that didn't last when everything went to the way it was before.

Of course here have businesses burning construction waste openly doesn't help. Here I live near a pallet factory that like to try to smoke us all out and there isn't a thing we can do about it as the government allows it to happen because they collect a lot taxes off this business. I did raise problem for them when they start importing construction waste from a local trash company and was burning it as if it was pallet factory waste. Some companies will do anything for money. Yet here I do whatever I can to offset their polluting by trying to recycle everything I can.

It’s a misprint. Your maths is correct.