Go Back   TeamTalk > Maintenance Tips, How-tos and Refurbishing Topics > Engine / Drive Train

Reply
 
Thread Tools Display Modes
  #1  
Old 06-23-2018, 07:06 PM
tr6coug's Avatar
tr6coug tr6coug is offline
MC Fanatic
 
Join Date: Aug 2007
Boat: Mastercraft 2007 X2 MCX
Location: OR
Posts: 847
MCX Engine losing power at low RPM

My '07 MCX is loosing power at low RPM. Last week on the lake at around 1500 RPM it would briefly drop rpms and sometimes die. Started up OK and idles OK. At higher RPM it runs better but not perfect. I'm not getting any check engine warning!

So, I immediately thought it was a fuel pump/filter. Today on the drive way I put a pressure gauge on it and its holding steady at 56 psi even though at 1200-1500 rpm the revs go up and down about 100 rpm.

This is the original fuel pump & filter and I do have a replacement pump and filter, but I don't want to pull that out of the tank if its not the problem.

Any ideas?
__________________
'07 Navy Blue X2 MCX
http://www.wakeblaster.com/
Ballast Timer Reprogramming Info

Last edited by tr6coug; 06-23-2018 at 07:22 PM.
Reply With Quote
  #2  
Old 06-23-2018, 09:10 PM
snork snork is offline
MC Maniac
 
Join Date: Jul 2007
Boat: 07 xstar
Location: south
Posts: 2,713
depending on the engine hours, it could become a problem, change it out and be done with it
what youre experiencing could also be bad gas
Reply With Quote
  #3  
Old 06-23-2018, 09:19 PM
tr6coug's Avatar
tr6coug tr6coug is offline
MC Fanatic
 
Join Date: Aug 2007
Boat: Mastercraft 2007 X2 MCX
Location: OR
Posts: 847
Quote:
Originally Posted by snork View Post
depending on the engine hours, it could become a problem, change it out and be done with it
what youre experiencing could also be bad gas
It might be bad gas. I'm changing out the plugs, wires, distributor and rotor now since that hasn't been done in several years. If its still acting up I'll fill it with non-ethanol and see if it improves.
__________________
'07 Navy Blue X2 MCX
http://www.wakeblaster.com/
Ballast Timer Reprogramming Info
Reply With Quote
  #4  
Old 06-23-2018, 09:48 PM
lakedrum03's Avatar
lakedrum03 lakedrum03 is offline
MC Fanatic
 
Join Date: Jul 2017
Boat: 2003 X-Series MCX
Location: Ohio
Posts: 536
Sounds like bad gas to me.
__________________
Being on a boat that's moving through the water, it's so clear. Everything falls into place in terms of what's important and what's not. - James Taylor
Reply With Quote
  #5  
Old 06-23-2018, 10:33 PM
CruisinGA's Avatar
CruisinGA CruisinGA is offline
MC Devotee
 
Join Date: Jun 2009
Boat: '01 X9 330HP
Location: Georgia
Posts: 2,324
I’m not sure what it is, but checking fuel pressure in the driveway with no load is not the same as checking under load. Takes a lot less fuel to rev in the driveway vs pushing the boat to speed. However, I would expect a fuel supply issue to show up more at higher speeds than moderate like you mention
__________________
Bailey
'02 X-9
Lake Blue Ridge
Reply With Quote
  #6  
Old 06-23-2018, 11:55 PM
tr6coug's Avatar
tr6coug tr6coug is offline
MC Fanatic
 
Join Date: Aug 2007
Boat: Mastercraft 2007 X2 MCX
Location: OR
Posts: 847
I changed out the cap/rotor and plugs. It seems to be running better now on the driveway. Taking it to the lake tomorrow to give it a good test.
__________________
'07 Navy Blue X2 MCX
http://www.wakeblaster.com/
Ballast Timer Reprogramming Info
Reply With Quote
  #7  
Old 06-24-2018, 08:35 AM
jj4smith jj4smith is offline
TT Regular
 
Join Date: Feb 2012
Boat: mastercraft, maristar, 1995
Location: midwest
Posts: 83
Iíve been having a similar issue. Did you end up testing it?


Sent from my iPhone using Tapatalk
Reply With Quote
  #8  
Old 06-24-2018, 09:10 AM
CantRepeat's Avatar
CantRepeat CantRepeat is offline
 
Join Date: Jul 2008
Boat: Passively looking for a CSX 265
Location: Roll Tide!!
Posts: 14,508
Sodar had an issue where the engine would hunt at low rpm. Turned out to be a bad pedal position sensor at the helm. If that turns out to be the case this thread has the part number and is 80 bucks.

https://www.mastercraft.com/teamtalk...ad.php?t=56678
__________________
Tim

"Heavy" beer is for wine drinkers that are too embarrassed to drink wine in front of their buddies. "Light" beer is a drinkin' man's beer!
Reply With Quote
  #9  
Old 06-24-2018, 05:40 PM
tr6coug's Avatar
tr6coug tr6coug is offline
MC Fanatic
 
Join Date: Aug 2007
Boat: Mastercraft 2007 X2 MCX
Location: OR
Posts: 847
So it IS the fuel pump. Got to the lake today and around 1200rpm fuel pressure was all over the place. Up near 50 then down below 20psi.
__________________
'07 Navy Blue X2 MCX
http://www.wakeblaster.com/
Ballast Timer Reprogramming Info

Last edited by tr6coug; 06-25-2018 at 01:17 AM.
Reply With Quote
  #10  
Old 06-25-2018, 09:23 AM
Cumminscj Cumminscj is offline
TT Enthusiast
 
Join Date: Oct 2016
Boat: 86 Magnum Skier
Location: Southeast
Posts: 276
Let us know if the pump fixes it. Sometimes fluttering fuel pressures can be the regulator.
__________________
1986 Marlin Magnum Skiier-sold
2000 Maristar 210VRS-weekend ride
1996 205 with LT1 cracked block-winter project
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


All times are GMT -4. The time now is 01:17 PM.


2018