running a 4 stroke for a time on 2 stoke mix

[patrol50]

mate mentioned he accidently ran his 4 stroke yammy 60 hp on a 2 stroke 1 in 50 mix the other day and asked me if i knew what could happen - he picked up the wrong fuel tank ( had 2 portable fuel tanks the same ) and connected her up and off they went - apparently bit of smoke etc and was running a bit rough and finally realized somthing was maybe a bit amiss but by then was out in the bay and had to motor slowly back - interested to know what sort of issues this is likely to cause re damage (if any) to a 4 stroke efi ob - and no it was'nt me that did it
cheers rob

[captain rednut]

hi rob
it wont hurt it, short term maybe a couple of tanks? ok, long term a dozen tanks? not good.
thanks jim

[White Pointer]

G'day,

I suggest pull the spark plugs and see if they are fouled. If they are replace them to ensure clean spark. It means the rest of the combustion chamber will be fouled as well.

The mix should not have caused excessive heating, so no long term damage should have occured. I suggest that a few tankfulls of BP Ultimate or an equivalent cleaning fuel will clean out any rubbish.

White Pointer

[black runner]

It would pay to give it a long run on new fuel asap and not let it sit around for any length of time with 2 stroke mix in the fuel system.

Having said that I have been running my 30 yr old B&S 4st mower engine on left over 2stroke mix for he last 5 years;D It loves it!

[patrol50]

thanks guys appreciate the imput as always good to get another opinion - did feel was probably ok but will now tell him to give it a good run on straight unleaded to clean it out
cheers rob

[White Pointer]

thanks guys appreciate the imput as always good to get another opinion - did feel was probably ok but will now tell him to give it a good run on straight unleaded to clean it out
cheers rob

G'day,

Not straight unleaded to clean it. You need a fuel that will clean the fuel injection system and the valves. Three tanks of BP Ultimate 98 should do it.

White Pointer