2-stroke carburettor problem

[skyflyer]

Mariner 2.5hp two stroke

My outboard was running fine at end of last year, (Late September) and on trying it today at home it started but almost immediately cut out.
I stripped everything and put in new fuel. That helped a bit but still it would only run at idle and the slightest increase of throttle and it died.

I then took carb apart and could see no sign of any obstruction or blockage. Eventually I replaced the carb entirely (as I had a spare from previous defunct outboard). It ran fine.

so something has happened over winter within the original carb. I‘M just curious as to what! If it has “gummed up” it’s a microscopiclly thin layer as all jets and ports looked clean as a whistle.

its A much newer carb than the old one I put on so I’m keen to get it going if I can. I noticed the size of the screw in jet that sits in the fuel bowl is not The same in the two carbs but that doesn’t explain how it was working before and now doesn’t!

 

[penfold]

Give the drilled holes in the carb a dousing in aerosol carburettor cleaner and a blow out with compressed air if you have it; there will be clag in a small hole somewhere.

 

[TernVI]

As above, but you could also check the float valve is flowing a proper amount of petrol.

 

[Adios]

Agreed if carb cleaner doesn't work you really need to take the float valve out and check it, i've had to replace one where the aluminium swelled with corrosion enough to reduce the flow, there's not much gap around it as it is