Engine hard to start

[rutstyrelic]

Hi first timer wondering if your brain trust can help me out.
I have a 40VETO 2 Stroke that sat for a few months while rebuilding the floors of the boat.
The 1st time I started it was slow to start but ran ok
The next day I put fresh fuel in it and it started fine then started to run rough and stalling at idle after a few seconds.
The fuel is not the issue I used the same fuel in my other boat and all good.
I’m guessing it is the carbies but don’t want to strip it down without asking you guys first
Cheers

[DennisG01]

I think you're on the right track, especially if you don't religiously use a good additive like Startron (or similar). You "might" get lucky with adding a very healthy dose of something like Mercury's Quickleen to your fuel and running that through for at least a few gallons. It might clean things up - and it certainly can't hurt. There's probably other products that have similar effects - Seafoam, for example. But I know that Quickleen is purposefully designed for this and does well (according to a few mechanics that I know). If it doesn't help after a few gallons, or maybe 6, then you probably need to disassemble and clean.

[99yam40]

you did not mention draining the tank and putting then in the fresh fuel,
so adding fresh to old bad fuel just gets you more bad fuel

[robert graham]

Try draining each carb onto a clean white rag to try to get an idea of any water or debris in float chamber….I do this and spray carb cleaner into the drain hole to possibly loosen debris in there…

[rutstyrelic]

99yam40. The tank was cleaned before putting the first lot of fuel.

[rutstyrelic]

Thank you all for your help. After draining each carby and seeing the colour of the fuel in the bottom carby in particular I decided to strip them down and discovered blocked jets as well as significant crud that the cover on the jet had fallen out and glued itself to the bottom of the bowl.
All back together now and purring like kitten again.
Cheers

[DennisG01]

Good! Thanks for posting back.

[robert graham]

Maybe consider installing a fuel/water separator type cartridge filter on the inside of transom…really helps with water/ debris in fuel…..Walmart/Atwood is a good unit for about $28 and easy to install….