2000 Epic 22...cutting out at > 1/2 throttle.

[sirsleepalot]

Looking for insight.  I've lost a lot of power off idle and my engine will cut out intermittently at greater than 1/2 throttle.  It doesn't stall but will act like it's hesitating when it's under load with a tube or heavy wakeboarder.  It always starts easily and idles without problem.  I noticed a hole in a water hose feeding the exhaust.  Hole is approx 1/4"L x 1/16"W where it's become weak and rubbed against the serpentine belt on the front.  I'm going to replace the hose tomorrow, but looking for advice as to good starting points to investigate.  Boat gets winterized every year by my marina with oil change, new oil filter, new fuel filter and fresh plugs in July this year.  I might have put 20 hours on it since dewinterizing in April/May.  I haven't pulled the fuel filter yet, but will since it feels like a fuel delivery/metering issue.  I wanted to see what you guys thought.  Any advice is welcome. 

[ktdust]

Start with the easy things and work towards the more difficult. I had the same problem when I first got my boat. Turned out to be dirty spark arrestor and Mass Air Flow (MAF) Sensor. Try taking them both out and cleaning the spark arrestor with throttle body cleaner, rinse, dry and reinstall. Clean the MAF with SensorKleen, let dry and reinstall. It should eliminate the 'hole' at half throttle. If that doesn't work check that both fuel pumps are running by pressing the red primer button on the back of the engine.

[sirsleepalot]

I'll give them both a shot and report.  The advice is greatly appreciated.  I had a second issue I forgot to include in the OP.  I seem to be taking on a decent amount of water but can't figure out where.  The scupper drains in the rear appear to be working as one way valves should.  The bilge is working fine when there's water in the bilge area.  Most of my water seems to be coming from the starboard side in the rear.  I'm using the trunk for a far sac locker and the lines to and from the fat sac are checked off at the ballast pump.  Any common areas to look for water intrusion? 

[sirsleepalot]

I did get water line changed out tonight and gave it another run.  Here's some extra symptoms:

1.  Lots of power loss
2.  Poor/sluggish throttle response at greater than 1500k
3.  Very slow to accelerate from idle
4.  Wants to lurch or hesitate when running at constant throttle position
5.  starts fine, idles fine and will restart without difficulty.

[blindside]

Spark plugs are the most common problem for me. Have to replace them every year or two. Has the same symptoms.

[wakejunky]

I would check to make sure both fuel pumps are working and if so ditto on the spark plugs. 3 years ago I went through 3 sets of plugs . Granted I put 130 hrs on it that summer

[sirsleepalot]

I removed the flame arrestor and MAF sensor.  Both were fairly dirty.  A good cleaning to all parts fixed the power outage.  How often do you guys change your fuel filters?  I've read the manual.  I usually go by hours rather than time periods.  I'll need to do that this off season and a few other upkeep things. 

[blindside]

Great news. I need to clean mine! It's never been cleaned.

[blindside]

Cleaned the flame arrestor and boat starts faster and seems to use less gas. It was fairly dirty.

[IndianaEPIC21]

Starting to get boat ready for Memorial Day here in Indiana.  I am pretty handy but a novice engine guy so I don't want to create a future problem.  I see cleaning the MAF sensor mentioned a lot.  I want to run the prevent and clean it before a problem occurs as I do see belt wear debris.  How do you gain access to the MAF sensor and how do you clean it?

[ktdust]

Check my previous post from this thread for how to clean the MAF. It's installed the backside of the air intake on the top front of the  engine. If You download the engine manual under the maintenance tab it should give you an illustration. Real easy to do. Just unclip the electrical connector and remove the two bolts to remove the MAF.

Good luck.

[ktdust]

IndianaEPIC21,

Take a look at page SF-27 on the M1UZ Shop Manual under the maintenance tab. It will show you the exact location of the MAF. I think toyota freak may have also had a post showing the 'dust bunny/ghost turd' in his MAF.