Like Tree0Likes

Fuel Pumps Questions.

Reply
Old 10-30-2004, 07:46 AM
  #31
GLH
Platinum Member
Platinum Member
Thread Starter
 
GLH's Avatar
 
Join Date: Dec 2002
Location: Burlington, VT
My Boats: Azimut
Posts: 15,267
Default Re: Fuel Pumps Questions.

Quote:
Originally Posted by Lmarth
To build on what 42MTI said (Post #8),the 800SC & 900SC use a different pump (p/n 821031) than the 600SC. After following 'more motivation', we're all probably thinking, who cares?
My mech is looking into that with Merc Racing but from my research it looks like the pump for 800&900sc's run off a pushrod mines are off a cam so I wonder if it is compatible.

More motivation...
Attached Thumbnails
Fuel Pumps Questions.-1bikinibabes011-meda.jpg  
GLH is offline  
Reply With Quote
Old 10-30-2004, 08:41 AM
  #32
Gold Member
Gold Member
 
Join Date: Oct 2002
Location: Fairport,NY
My Boats: 1998 Hustler Slingshot
Posts: 747
Default Re: Fuel Pumps Questions.

GLH- Good catch! I really don't know. You're right, my 800SC's have the pushrod. The Merc website doesn't show a pushrod with the 600SC. Let us know what Merc says. This has gotta be right. Funny how we gravitated from 'motivation' to 'pushrods!'
Lmarth is offline  
Reply With Quote
Old 10-30-2004, 08:56 AM
  #33
Registered
 
Join Date: Aug 2003
Location: NEW YORK
My Boats: 1988 FOUNTAIN 33
Posts: 183
Default Re: Fuel Pumps Questions.

I have seen many fuel pumps that are fine but wrongly accused.
Check the fuel pickup screen for debri, & make sure the rest of the fuel lines are of sufficient diameter and no restrictions. The restricted fuel pickup is almost always the reason for a pressure drop after a long run. Try putting a vacuum gauge at the suction side of the pump, high vacuum & you have restriction that no pump will overcome.
JIMG is offline  
Reply With Quote
Old 10-30-2004, 09:46 AM
  #34
GLH
Platinum Member
Platinum Member
Thread Starter
 
GLH's Avatar
 
Join Date: Dec 2002
Location: Burlington, VT
My Boats: Azimut
Posts: 15,267
Default Re: Fuel Pumps Questions.

Quote:
Originally Posted by JIMG
I have seen many fuel pumps that are fine but wrongly accused.
Check the fuel pickup screen for debri, & make sure the rest of the fuel lines are of sufficient diameter and no restrictions. The restricted fuel pickup is almost always the reason for a pressure drop after a long run. Try putting a vacuum gauge at the suction side of the pump, high vacuum & you have restriction that no pump will overcome.
Thanks Jim checking for restriction was done everytime we changed the pumps and the cam.
My mech will again go thru the whole line next week before we head down to FL with the rig.
GLH is offline  
Reply With Quote
Old 10-30-2004, 09:51 AM
  #35
GLH
Platinum Member
Platinum Member
Thread Starter
 
GLH's Avatar
 
Join Date: Dec 2002
Location: Burlington, VT
My Boats: Azimut
Posts: 15,267
Default Re: Fuel Pumps Questions.

Quote:
Originally Posted by Lmarth
GLH- Good catch! I really don't know. You're right, my 800SC's have the pushrod.
I checked the pics of the parts at Bam Marine's website.

More motivation...
Attached Thumbnails
Fuel Pumps Questions.-babe.jpg  
GLH is offline  
Reply With Quote
Old 10-30-2004, 10:28 AM
  #36
GLH
Platinum Member
Platinum Member
Thread Starter
 
GLH's Avatar
 
Join Date: Dec 2002
Location: Burlington, VT
My Boats: Azimut
Posts: 15,267
Default Re: Fuel Pumps Questions.

Quote:
Originally Posted by sutphen30
motivation is working.have you checked the lines to the fuel pump,maybe its collapsing some where.what kind of line?
I will check this when I go up to the boat today I know they are hard lines passed the pump and rubber lines prior to the pump.

This is the merc stock rigging.

I've played with the contrast in order to see but here is how it is plumbed standard from Merc

Click on the pics for the big versions

Pic #1
You see the rooting from the tank to the electrical priming pump at the bottom right from there thru the fuel filter, from there along the center transom over the strainer to the mechnical pumps, the other rubber hose is the return from the mechanical pump.

Pic#2
Stainless hard pipe routing from mech pump up to the fuel rail feeding the two 700cfm Holley's, notice the electrical pressure sensor is at the end of the rail.

This set up is similar between the two engines and one works fine the other is driving me nuts
Attached Thumbnails
Fuel Pumps Questions.-fuel-line-routing.jpg   Fuel Pumps Questions.-routing-pump.jpg  
GLH is offline  
Reply With Quote
Old 10-30-2004, 10:34 AM
  #37
GLH
Platinum Member
Platinum Member
Thread Starter
 
GLH's Avatar
 
Join Date: Dec 2002
Location: Burlington, VT
My Boats: Azimut
Posts: 15,267
Default Re: Fuel Pumps Questions.

Keep the conversation coming....
Attached Thumbnails
Fuel Pumps Questions.-043_3360a.jpg  
GLH is offline  
Reply With Quote
Old 10-31-2004, 10:11 PM
  #38
Charter Member
Charter Member
 
rbtnt's Avatar
 
Join Date: Oct 2000
Location: Central, Ohio USA
My Boats: 2001 28 Eliminator Daytona
Posts: 1,074
Default Re: Fuel Pumps Questions.

I use the CV Products billet mechanical pumps on 650 hp motors. I changed the bases with the Mercury sea pump bases. This required drilling the treads out so they would screw together. I tapped the holes as BenPerfected did for the overflow line.

This made for a clean install, but was a little pricey. If you're paying someone to do your work, this would be cheaper than electric pumps with all the plumbing, wiring, safety switches, etc.

The only drawback I have is if I take the fuel bowls off put them back on, I have to fill them manually through the side plugs.
rbtnt is offline  
Reply With Quote
Reply

Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
turbosonoma
General Q & A
1
10-09-2007 01:25 AM
dyno
General Q & A
3
11-22-2004 08:07 PM
Shah Mat
General Q & A
3
07-03-2004 01:42 AM
35/25
General Q & A
4
09-15-2003 12:42 PM
XCAV8
General Q & A
19
06-23-2003 07:59 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 09:35 PM.


Copyright 2011 OffShoreOnly. All rights reserved.