Outboard problems fuel?

[sailabroad]

I have a 3 year old Yamaha F2.5A that is refusing to start. Im stuck for finding the cause.

It's run rougher and rougher until now where it just does not start. The local mechanic suggests the Yamaha carb cannot handle the local gasoline(
We are Bonaire where the gasoline is from Venezuela) but everyone else here seems to be OK except for me.

I cleaned the carburetor with solvent and blew the 2 jets with clean compressed air, spark gap and spark are good. Compression seems fine with some bounce-back, choke can engage and disngage, fuel filter is not blocked and clean, tried 2 different fuel sources here, I haven't touched the fuel air mix as it requires a special tool. The carb gaskets look OK but I will replace them, and will check valves today.

One weird thing I found was sometimes there is a puff of escaping air from the intake manifold into the carb, not sure if that's normal?
Another thing it seems there was a little oil above the piston (perhaps when the outboard wasn't stored at quite the right orientation) .

When I cleaned the carb I accidentally bent the float valve and it was flooding, I didn't notice this for a while and it might have leaked into the oil but only a tiny amount, the oil was changed when I started having problems.

Does anyone have any tips for checking an outboard, anything that might lead me somewhere? STUCK!

Thanks, I would really appreciate any input, ideas or even musings!

[sailormed]

Take out spark plug. Start and check for spark. Air filter clean?


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[tkeithlu]

Try starting with choke, fail, then pull plug. Wet- too rich, start without or with less choke and maybe more air (throttle). Dry- you're not getting gas to the cylinder for any of several reasons. Similar test - squirt with ether. If it starts and then dies, you're not getting fuel to the cylinder.

[RaymondR]

I have found that I need to replace spark plugs fairly regularly these days. The problem appears to be fuel related but disappears with a new set of plugs. I suspect it's related to the inbuilt resisters they have.

[sailabroad]

Thanks for the replies, I finally found the problem!!

(1) The float was over adjusted and was blocking all fuel and (2) i had dropped a tiny part of the idle jet, it must have fallen out when I opened the carb!

All is working well again!