Tohatsu 18MFS B2 starts and runs fine low rpm, but dies in high rpm after 10 sec

[_tp_]

Hi, my 4-stroke tohatsu worked fine few days after I changed new sparks and cleaned carburetor with appropriate liquid. Then, after a low-rpm use in fishing-trip started to die suddenly when using full rpm about 10 sec. Changed the the hand-pump and fuel line from tank to motor - no help. Using the hand pump when problem occurs doesn't help, but if I pump between high and low throttle, engine often somehow stays running and I can use full throttle 10 sec again.
Is the fuel pump worth of changing or should I try something else first?

 

[Sea Rider]

Welcome to Iboats,

Is fuel tank, internal mesh filter and fuel pump filter immaculate clean ? You changed a complete fuel line or only parts ? The engine has issues at idle or when opening throthle ? You can always rebuild a fuel pump if defective, or buy a new one if that's not much price difference. BTW, how old is that engine, you bought it new or second hand ?

Happy Boating

 

[_tp_]

Idle is very nice and full throthle too, only issue (for years) is slight jerk when changing from low to full throthle. This new problem started without warning.
I bought Tohatsu as new 5 years ago and have used it less than 300 hrs. Changed complete fuel line from fuel filter to tank and filter looks clean. Tank has been changed to 'Little Joe' 2 years ago due to the theft.

Btw, some kind of soot or roughness seems to be after carburetor (picture), may it be symptom of something that is wrong...?

 

[pvanv]

Verify oil level and clean the carb correctly, then re-check.