fuel filter mariner 40hp

[g agus t]

hi all.

went for a trip during the week, engine stopped after 10 min, could not restart it. had the problem before and it was always the carbureto. next day went down to take it out but i noticed there something dark high in the fuel filter. unscrewed it and poured it into a container. it appears to be water and two stroke oil. its a mariner 40hp, 2 stroke, auto lube.

any ideas what is wrong ?

[JOHN1]

thats a lot of water, is there any chance you left your tank out in all of the wet weather and left the vent wide open, too much water there for it to be condensation imo .

[g agus t]

tank was closed. anyway i cleaned it and restarted the engine...smokey at first but then cleared. ran it for 45 min...no probs. next day returned to the boat...same problem again

[JOHN1]

there is a small possibility that water is getting into your two stroke tank, and getting into fuel filter that way .

[donal domeney]

by any chance is it fuel that was left in the tank since last year.

[g agus t]

tank was closed. anyway i cleaned it and restarted the engine...smokey at first but then cleared. ran it for 45 min...no probs. next day returned to the boat...same problem again

will check it out but its doubtful...its not easy too take unscrew the cap, it seals very well

[fishfeatures]

use fresh fuel, rinse out the tank if its a portable one, change the fuel filter and see if that helps.

[g agus t]

but why is there 2 stroke oil in the filter. only pure petrol goes through it and after leaving that it heads for the auto lube mixer which blends the petrol with the oil.

[fishfeatures]

if there's oil in a filter where you're sure only petrol goes through then your auto lube system must be forcing it back into the filter. Anybody messing around with your fuelpump or anything recently..

Have you a year or serial number for your engine..

[g agus t]

no one, it has not been touched. its an 40hp mariner 2 stroke 1998 i think

[g agus t]

serial number 9936152

[fishfeatures]

serial number 9936152

couldn't find that number, is there any other one on the engine?

Anyway are you sure it's two stroke in the filter as I had a look at the autoblend on another one from around that era and it does feed oil straight to the carbs which i reckon yours does too.... can't see how it can be brought back through the fuel pump and into the filter....

If you want ,you can try disconnecting the oil supply to the carbs (plug the pipes tight ) and mix up a portable tank at 50:1 and see if that solves the problem. If it does then we know that there is something going on with the autoblend.

[g agus t]

here is the lay out of the fuel and oil system

[fishfeatures]

ah now we can see.... i revert to my original post as the oil and fuel is mixied before the pump. if there is water in the filter like you say then it's coming from the tank. Check all fuel lines , primer ball and the tank itself for leaks or cracks... if the tank is not built in, wash it out with petrol, and put some new fresh stuff in.

[g agus t]

but i will ask again...how is the 2 stroke oil getting into the filter. the oil pump is at the bottom of the engine....the filter is on top. in reality the fuel filter is next to the carburetor as per the diagram above. i understand about the water and i will check all that out later.

[MAC]

Are you sure it was 2 stroke oil? Could be crud from the bottom of the tank?? Any 2 stroke oil would normally mix with the fuel in the filter and you get coloured fuel, rather that a build up of oil??

Kev

[g agus t]

look at the filter in the photo. the top of the filter has oil in it. it is the same colour as two stroke. the oil and petrol are automatically mixed after the filter so two stroke oil never gets near the filter. the oil pump releases enough oil to the petrol before it gets to the carbuteror....thats where the mixing is done. its called auto lube or auto blend. if you follow the diagram you can see that.

[fishfeatures]

i can only think that the oil was either sucked back through the lines somehow maybe an unvented tank or else it was pushed back that far somehow from the oil pump. strange one though.