2017 175 Pro XS s/n 2B399702
Recent maintenance: Plugs replaced (the good ones from the Merc shop). Replaced primer bulb with OEM bulb.
The last time the motor ran wide open was November. Ran it on the muffs a few times since
First trip after the maintenance, I did a lot of idling. Finally made it to a boat lane and decided to stretch its legs. Throttle down and the motor does like it should for 30 seconds then starts spitting and sputtering and falls on its face. Throttle back to idle and it catches up to itself and idles fine. Try to go WOT and it just spits and sputters and bogs down. Still idles fine. Let it idle a while, and it will run for 30 seconds again. One time I let it idle for a while, gave it WOT just to get it on plane, then backed off to 2800ish RPM and it ran a lot longer before it again spit and sputtered and fell on its face.
Replaced fuel filter. Nothing changed. Ran a hose from the ball inlet to an external gas can to isolate the boat fuel system. Nothing changed. Thought maybe I pinched a fuel hose when I dropped the lower cowling, but hoses seem free to move. Any ideas? Thanks in advance!
And I did check the plugs and wires for security and all good.