Notices

3800 rpm wall

Thread Tools
 
Old 10-19-2013, 09:40 AM
  #21  
Registered
iTrader: (3)
 
Join Date: Oct 2007
Location: yorkville,il
Posts: 8,427
Received 87 Likes on 49 Posts
Default

this may sound stupid but did you change the fuel filter,it does not take much water to impede the fuel flow and pressure.
mike tkach is offline  
Old 10-19-2013, 09:55 AM
  #22  
Registered
iTrader: (3)
 
Join Date: Apr 2006
Location: Toledo Oh
Posts: 10,061
Received 690 Likes on 276 Posts
Default

Originally Posted by Knot 4 Me
Not aware of a VST tank on a 7.4L MPI.
mine has one, it also houses the 650 dollar fuel pump.......

[ATTACH=CONFIG]510282[/ATTACH]
Attached Thumbnails 3800 rpm wall-gedc0996-2-.jpg  
phragle is offline  
Old 10-21-2013, 03:43 PM
  #23  
Registered
Thread Starter
 
Join Date: Oct 2013
Location: Buckner, KY
Posts: 32
Likes: 0
Received 0 Likes on 0 Posts
Default

I just ran this thing on the trailer and it runs up to 4800 smooth as silk. Hits the rev limiter at 4900. Runs fine not under a load. I'm going to put a fuel pressure gauge on it and run it in the water to see exactly what I'm getting under load at WOT, also taking some spray to squirt in the intake to see if RPM's go up to try and narrow it down to fuel pump problem.

Last edited by Toolman62; 10-21-2013 at 04:23 PM.
Toolman62 is offline  
Old 10-21-2013, 03:50 PM
  #24  
Registered
iTrader: (2)
 
Join Date: Mar 2002
Location: Miami Beach
Posts: 2,142
Received 3 Likes on 2 Posts
Default

Originally Posted by Toolman62
I just ran this thing on the trailer and it runs up to 4800 smooth as silk. Hits the rev limiter at 4900. Runs fine not under a load. I'm going to put a fuel pressure gauge on it and run it in the water to see exactly what I'm getting under load at WOT, also taking some spray to squirt in the intake to see if RPM's go up to try and narrow it down to fuel pressure problem.
how did you get enough cooling water to the motor on the trailer? Curious because my engines pump more than the hose will give at anything over 1000 rpms.
pstorti is offline  
Old 10-21-2013, 04:22 PM
  #25  
Registered
Thread Starter
 
Join Date: Oct 2013
Location: Buckner, KY
Posts: 32
Likes: 0
Received 0 Likes on 0 Posts
Default

Hose wide open with deep water pickup! Temp runs around 170. Plus just bounced the rev limiter, didn't hold it at a high RPM very long

Last edited by Toolman62; 10-21-2013 at 04:24 PM.
Toolman62 is offline  
Old 10-21-2013, 09:43 PM
  #26  
Registered
 
Join Date: Oct 2008
Location: Slidell, La.
Posts: 1,634
Received 32 Likes on 16 Posts
Default

My 350 mag did that when timing was off, under load it cough and sputtered?? On hose ran fine.
nailit is offline  
Old 10-22-2013, 01:36 AM
  #27  
Charter Member # 55
Charter Member
 
Griff's Avatar
 
Join Date: Oct 2000
Location: Omaha/LOTO
Posts: 19,558
Received 1,821 Likes on 907 Posts
Default

Originally Posted by Toolman62
I just ran this thing on the trailer and it runs up to 4800 smooth as silk. Hits the rev limiter at 4900. Runs fine not under a load. I'm going to put a fuel pressure gauge on it and run it in the water to see exactly what I'm getting under load at WOT, also taking some spray to squirt in the intake to see if RPM's go up to try and narrow it down to fuel pump problem.
Youu said you had 80% and 60% leakdown on 2 cylinders and stopped after that......DING!!!! DING!!!!

No fuel issue is going to cause that. The engine needs to come apart.
Griff is offline  
Old 10-22-2013, 07:51 AM
  #28  
Registered
Thread Starter
 
Join Date: Oct 2013
Location: Buckner, KY
Posts: 32
Likes: 0
Received 0 Likes on 0 Posts
Cool

Griff I agree about the rebuild!! I'm going to do my own leak down test to confirm results from service. If this is the case then I think that I'm just running out of HP because of loosing power from the week cylinders. 57 mph at 3800 with the equivalent of a 5.5L in a 4200 lb boat running a 23P prop isn't to bad. She should come up and be happy with all cylinders working again
Toolman62 is offline  
Old 10-22-2013, 08:03 AM
  #29  
Registered
iTrader: (5)
 
Join Date: Jul 2009
Location: Taunton Ma
Posts: 8,527
Received 698 Likes on 341 Posts
Default

If that motor doesn't run like a complete piece of $hit at all rpm then those results are wrong.
Unlimited jd is offline  
Old 10-22-2013, 08:10 AM
  #30  
Registered
 
Knot 4 Me's Avatar
 
Join Date: Jun 2005
Location: Central IL
Posts: 8,363
Received 749 Likes on 402 Posts
Default

Originally Posted by phragle
mine has one, it also houses the 650 dollar fuel pump.......

[ATTACH=CONFIG]510282[/ATTACH]
Yours is the older LX with the Lingenfelter intake. The L29's like his will not have that.
Knot 4 Me is online now  


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.