Outboard advise needed please!

[Iva-Cod-on]

Its for a mate of mine he has a second hand Tohatsu 3 to 4 hp four stroke and was across the lakes with the boat but after a couple of hours running it started to splutter then chucked it then after that each time it started it would'nt pick up in power, he changed the plug and got it briefly checked by a local boat yard and the plug is ok and no water etc in fuel the bloke that checked it sugested the carb any advise would be great??

[mark]

built in fuel tank or external?

if its external... there's a brass nut on the bottom of the carb bowl, crack it open half a turn and pump the primer bulb for 20 seconds or so, that should flush out the carb bowls and any debris that might be sticking the jets

if you see air bubbles coming out as you pump it, there's a crack in the fuel line somewhere sucking air in, possibly be the fuel pump diaphragm traingular ish or shquarish metal disk with a fuel line at each end. take the cover off and check the diaphragm aint cracked/perished

also check the fuel lines for tight fit

[Iva-Cod-on]

Thanks Mark thats spot on I'll check those for the lad thanks again i'll let you know how I get on

[mark]

sounds like it might be sucking air in somewhere...

that said could be loads of other things as well

a compression test will confirm the engine itself is ok

[Iva-Cod-on]

Sorry to be a pain but just spoken to the lad and it's an internal tank Mark any other ideas?