Seahorse ETL70

[JD010257]

I have a problem with a Seahorse ETL7077. Starts and idles in gear or out of gear with no problem every time. Accelerate and it will die, if accelerated in small progressive movements the motor will stumble along, seem to pick up and then be fully responsive. It will run no problems for as long as required, if it is stopped and started within 5 minutes the motor is still fully responsive. If you stop for anything longer than that 5 minutes the motor will do the same thing die on constant accelaration or will stumble and pick up slowly with slow progressive accelaration. The motor has been serviced, new plugs, compression is good, ignition good.
I have put a kit though the fuel pump, replaced the fuel line, replaced all the fuel hoses between the motor body and each carbi ( thinking it may be sucking air) any ideas?

[gapowell]

Had the same problem with my johnson 15 hrse '76 model. I ran some sea foam through it and ran it for an entire afternoon. It gradually got better and better and before long could run it wide open!! I had pretty much given up on the motor!

[JD010257]

Have run a carbi cleaner that is designed to be added to the fuel, still same problem!

Any other suggestions?

[hornsfan]

Does your fuel cap have a screw on top?

If yes, it has to be open for fuel to flow freely.

I had a similar sounding problem with a boat I bought recently that didn't want to run until I figured out that the screw was closed.

Ran good after that!