2005 df140 surge. Fuel or mechanical (video)

[90mustang]

Hello all
Here is my situation. Purchased boat knowing it had a previous fuel issue from sitting. After changing all the filters including vst and draining and fuel tank completely the boat ran great for two outings. Noticed water in the separator so I drained it and filled it with fuel and reinstalled . I then flushed the motor and after running for 15min the boat shut off and would not restart. Noticed no fuel was in the separator. Tried priming but I could not pull fuel from the tank. Removed filter and filled with fuel. Primed the bulb and the motor fired and ran for another 15 min ans shut off. The separator was installed with 2 90's which seemed restrictive so I changed it out with a head with straight fittings. Was able to prime and run the boat for longer than half hour without issue. The boat then sat for a month and a half. Took it out yesterday and it would not get up on a plane or rev past 3000. Once it got up to about 2500 it would bog and surge. In the driveway it runs smooth up until the safety kicks in at 3000.

A few questions
Purpose of the first fuel pump? Could I have burned it up when it was running it and not pulling fuel?

Are the fuel lines under the cowl supposed to be really soft?

Looking at the video does anyone think spark related as opposed to fuel.

Thanks!!

[MarshMarlowe]

Where's the video?

So you changed the VST, or drained it, or?

A similar surge issue on a DF140 was described in this thread on THT
Suzuki DF140 fuel problem fix - The Hull Truth - Boating and Fishing Forum

The fix involved removing the VST tank and cleaning it out

My understanding is that the low pressure fuel pump serves to keep the fuel primed to the engine.

When you're running the engine and it begins to surge, have you tried squeezing the primer bulb while this is happening? If so, what happened (if anything)?

I had a surge issue once on my old DF140, but the symptoms were different than what you describe. The Suzuki OEM fuel lines are very soft, and prone to kinking. This was my issue on my DF140. The fuel line had kinked in front of the engine, and caused my engine to surge violently after 5000 RPMs. I rerigged with stiffer fuel lines and a Yamaha primer bulb. This fixed the surging on my engine.

Here's a video of what my engine was doing
https://www.youtube.com/watch?v=6Ht6pkbYOQs

[aquamort]

Could be a number of things, but one quick one...the Breather? Is the primer sucking in? Does it run ok with tank cap off?