2013 250 Pro XS - surging/bogging above mid-RPM range

[WalleyeRanger]

2013 250 Pro XS, 112 Hours

Serial # 1B963022

2013 250 Pro XS
23 Pitch Bravo I XS
5750 WOT
~4psi idle/20psi WOT water pressure
smartcraft gauges


First encountered this problem July 3, 2018. Fished for a few hours in the early am and found a nice bunch of smallmouth, called the family to see if any of the kids wanted to join me and met them back at the launch. Was running back out to the spot ~3 miles away (running trimmed mostly down, around 4000 rpm) and engine bogged for a second. I pulled back on the throttle, it ran smooth. Pulled back to idle and checked smartcraft for any alarms, none. Throttled up and it ran clean. Later in the day while tubing the kids around it happened again and I cut it, called it a day.

Brought it in to a Ranger/Merc dealer and they put it on the computer, no codes. They ran it for 20 minutes and no problems. Pulled up part of the floor and saw a fuel tank vent valve that others have had problems with in the past and replaced it. Told me I should be fine.

July 24, 2018 - launch the boat on first day of family vacation with nice water conditions, after an easy warm-up, thermostats cycle and I head across the bay to our cottage. After 30 second run, surging/bogging is (still) present. Ugh.

Take the rig in to the Merc mechanic up there, they ID a problem with fuel pressure. Apparently the high pressure pump had failed and my fuel pressure was only 35psi on the rail.

High pressure pump replaced, fuel pressure on rail (and air pressure) returned to spec.

July 27, 2018 - water conditions give window for boating, problem persists. Tech comes out and hooks up computer. We run drop tests on cylinders, suspect cylinder 4. Recommendation is to replace spark plugs 1st, then #4 coil pack if spark plug change does not correct the issue.

Having about $1200 into this issue, I'm feeling like the next steps are shots in the dark and would be interested in your thoughts and direction.

Thanks!



Video of problem:

Shows the engine from idle, holeshot, full throttle, power loss / surging. Skip to the 1 minute mark if you want to jump right to the trouble spot.

[Savage]

You need to have a technician lake test the boat with a CDS connected.

Watch the fuel and air pressures as the problem is occurring.

Watch the TPS as the problem is occurring.

[WalleyeRanger]

Thank you for the advice - I am going to get it back in front of a tech ASAP. This has been a very frustrating process...

[WalleyeRanger]

Update: Still problematic...

Short verison: Fuel and Air pressure were both varying when the problem was occurring. Consensus was that the compressor was not working well enough to feed engine at WOT. Replaced compressor - problem persists. Ugh.

I feel like we're chasing a ghost at this point.

[EuropeanAM]

Running out of fuel in VST.

Several steps to accurately identifying this problem. Good STARTING point is a separate portable fuel tank, with it's OWN line and bulb, connected directly to the engine. Go run and see if the problem persists. Problem GONE- it's in the BOAT fuel supply system.

Still present- it's inside the cowling.

Then we can look at potential causes based on that outcome... report back.

[WalleyeRanger]

Ran the motor on separate tank / line/bulb assy and problem persisted.

After multiple test runs and pressure readings, tech discovered that pressure from the boost pump was falling off over time (as we run the boat over 3500rpm). Hoping that new boost pump is the solution at this point.

That will make the repair saga come to:
1)new fuel tank vent
2) new High pressure fuel pump
3) new compressor
4) new boost pump

At this point I'm just anxious to get back on the water - been broken since July 3rd.

Will update!

[EuropeanAM]

Make sure the pulse pump is functioning properly, and that the hoses/fittings feeding it pulses from the crankcase are open.

Verify good REEDS. Especially on the two cylinders driving the pulse pump.

Verify needle, seat, and FLOAT SETTING (check float for wear or "dimple" where it contacts the needle).

Also inspect fuel pump harness carefully while out- have seen a few with poor connectors.

[WalleyeRanger]

Update:

Replaced Boost pump and rebuilt pulse pump.

Problem resolved!

[rocketman6965]

Make sure you get to keep old compressor. I'll bet there is nothing wrong with it. Glad you got it fixed.

[EuropeanAM]