Like Tree0Likes

575 sci acting up

Reply
Old 07-15-2008, 10:14 AM
  #11
Platinum Member
Platinum Member
Trade Score: (1)
 
JRider's Avatar
 
Join Date: Jul 2007
Location: MI
My Boats: DCB
Posts: 2,507
Default

Had a similar problem this weekend and it was a loose spark plug wire... You can always dump your water seperator in a coffee can and see what you have there.
JRider is offline  
Reply With Quote
Old 07-15-2008, 10:15 AM
  #12
Platinum Member
Platinum Member
 
Quiet Storm's Avatar
 
Join Date: Apr 2002
Location: Lake Michigan
Posts: 1,683
Default

It sounds more like your loosing the head gaskets. The head gasket material between the cylinders gets very thin on the 575's and will burn out causing cross firing. Especially if they are original Mercury gaskets.

Be carefull, it could cost you alot of money.
Quiet Storm is offline  
Reply With Quote
Old 07-15-2008, 10:36 AM
  #13
Platinum Member
Platinum Member
Trade Score: (1)
 
JRider's Avatar
 
Join Date: Jul 2007
Location: MI
My Boats: DCB
Posts: 2,507
Default

Quiet storm is correct...if you have over a 100hrs change them to atleast felpros 17048 gaskets. I just had mine changed and they were pretty much toasted between the cylinders. While you have it apart I would send the blower out for a refresh also. Already been down that road also.
JRider is offline  
Reply With Quote
Old 07-15-2008, 02:38 PM
  #14
Registered
 
Join Date: Aug 2007
Posts: 14
Default

What about a possible vacuum leak?
JOKER_FTW is offline  
Reply With Quote
Old 07-15-2008, 04:20 PM
  #15
Platinum Member
Platinum Member
 
Join Date: Jul 2006
Posts: 22
Default 575sci help

The head gaskets and heads were done @ 260hrs. I put felpro head gaskets on at that time. It has 395hrs on it now. The Iac reads 36 at idle. Injector on time is 2.4ms at idle. Doesn't the IAC only control idle? It runs rough at idle and at speed. It back fires through the throttle bodies when it back fires. I have replaced the following so far:
Distributer, module, wires, plugs, rotor, cap, solenoid.
Electric fuel pump. I took apart the mech. pump The diaphrams were fine. I even installed a temporary electric fuel pump to eliminate the mech. pump and a gas can to eliminate the tank and fuel line to the tank.
New MAP sensor.
Alternator (it actually was bad)
Fuel filter, fuel/water separator.
I have checked the vacuum line from the cool fuel regulator to the throttle body. I also checked the vacuum line from the map sensor to the intake. Is there some other vacuum line I'm missing? Any response or help would be appreciated.

Thanks again,
Dminnick is offline  
Reply With Quote
Old 07-15-2008, 04:34 PM
  #16
Registered
 
Join Date: Aug 2007
Posts: 14
Default

Try gapping the plugs down. Almost sounds like detonation to me.
JOKER_FTW is offline  
Reply With Quote
Old 07-15-2008, 05:07 PM
  #17
Platinum Member
Platinum Member
 
Join Date: Jul 2006
Posts: 22
Default

They are at 35. What do you recoomend and what would this tell me?

Thanks
Dminnick is offline  
Reply With Quote
Old 07-15-2008, 05:43 PM
  #18
Registered
 
Join Date: Aug 2007
Posts: 14
Default

I would try 32 and see if that improves it. Cant really recommend a gap, but im familiar with issues like this on turbo applications.
JOKER_FTW is offline  
Reply With Quote
Old 07-15-2008, 06:26 PM
  #19
Platinum Member
Platinum Member
 
Join Date: Jul 2006
Posts: 22
Default 575 Mef3 computer

Anybody ever heard or seen a Mef3 computer go bad? Who can test this? Jim @ Arizona speed said it would take about 2 weeks before they could get to it.

Thanks for all the ideas!!!
Dminnick is offline  
Reply With Quote
Old 07-15-2008, 09:17 PM
  #20
OSO Moderator
Charter Member
 
BillR's Avatar
 
Join Date: Oct 2000
Location: Virginia Beach, VA
My Boats: '00 Scarab Sport 302 CC
Posts: 3,580
Default

Get the IAC back down to 15 and try it. Betcha it will run properly.
575SCi's are picky about IAC setting.

If you had scan tool plugged in, why didn't you adjust it?
It is adjusted by what looks like idle screw on fron throttle body. Careful-you don't need to turn it too much. Let it settle - then blip throttle - let it settle and then check reading. Repeat as needed.
__________________
BillR

'00 Scarab Sport 302 CC
'02 Cigarette Top Gun TS
'02 PQ 340
'00 PQ 280
'98 Scarab 22
'97 Baja Outlaw 20
'72 Checkmate
'65 Glastron

Last edited by BillR; 07-15-2008 at 09:20 PM.
BillR is offline  
Reply With Quote
Reply

Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
lakeman2
General Q & A
7
09-17-2008 07:24 PM
dennis r
General Q & A
1
07-19-2007 09:34 PM
jharran
General Q & A
3
05-21-2007 10:15 AM
SuperiorOKC
General Boating Discussion
1
01-12-2007 04:09 PM
Quiet Storm
General Q & A
8
02-02-2003 12:02 AM



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
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -5. The time now is 04:24 AM.


Copyright 2011 OffShoreOnly. All rights reserved.