Go Back  Offshoreonly.com > Technical > General Q & A
Rapid Fire spark plugs questions. >

Rapid Fire spark plugs questions.

Notices

Rapid Fire spark plugs questions.

Thread Tools
 
Old 05-02-2003 | 09:59 PM
  #1  
US1 Fountain's Avatar
Thread Starter
Ginger or Mary Ann?
25 Year Member
Charter Member
 
Joined: Oct 2000
Posts: 11,030
Likes: 9
From: L
Default Rapid Fire spark plugs questions.

Stock '99 502 MPI motors.

Gonna pull both motors on Sun to replace the drive couplers. Figure thats the time to replace the plugs.

Anyways, did a search on the AC rapid fire #1 plugs, Seems everyone has had great results as far as cleaner transom and better idle. Correct????

What should I gap them at..... .035, or .040?

Will changing to these plugs effect any other settings? Timing, fuel mixture?

Thanks
US1 Fountain is offline  
Reply
Old 05-02-2003 | 10:04 PM
  #2  
obnoxus's Avatar
Charter Member #1171
20 Year Member
Charter Member
 
Joined: Feb 2001
Posts: 4,018
Likes: 21
From: Clearwater, FL
Default

.040
__________________
I want to live in a world where a chicken can cross the road and not have its motives questioned.
obnoxus is offline  
Reply
Old 05-03-2003 | 06:39 AM
  #3  
Raypanic's Avatar
Charter Member
 
Joined: Oct 2000
Posts: 1,560
Likes: 0
From: Lake Orion, MI. USA
Default

Ob, Why .040? My 2000 says .035. I have used this for 2 years now with no problems with the Rapidfire #1's.

Would not .040 require more voltage out of the coil to properly spark? Or is the merc coil able to provide the larger spark?
__________________
Ray
Raypanic is offline  
Reply
Old 05-03-2003 | 07:22 AM
  #4  
Registered
20 Year Member
 
Joined: Nov 2000
Posts: 1,418
Likes: 20
From: Westport, Kentucky
Default

Jerry,

I used the #1's and they cleaned up my transom a great deal when I was over-carbed on my old Holly. If you gap them at 40 there would be a theoretical performance gain. The #1 requires a little less voltage/current to produce the same energy under the same circumstances. Under higher cylinder pressure excess gap is bad. Spark may break down. With stock compression you should be fine. With the older Merc ignition setup a large gap places more "stress" on the ignition module and can lead to premature failure. A friend of mine used to maintain a fleet of tow boats in Florida and some NASCAR fan gapped them all at 45 prior to his arrival and many ignition modules failed. Merc denied the warranty claim.
BadDog is offline  
Reply
Old 05-03-2003 | 08:27 AM
  #5  
Fountainclimber's Avatar
Gold Member
 
Joined: Feb 2003
Posts: 428
Likes: 0
From: Sunny Florida
Default

FREE
4 new but old style Rapid Fire #1's These have fluted upper ceramic part. ACDelco techs said best not to mix with new style smooth style plugs.

I am trying the Bosch plugs now.

Fountainclimber
Fountainclimber is offline  
Reply
Old 05-03-2003 | 08:45 AM
  #6  
Macklin's Avatar
Registered
20 Year Member
 
Joined: Dec 2001
Posts: 1,914
Likes: 5
From: Virginia Beach
Default

I used Rapid Fire #1's in my 502mag mpi with great results. Much improved idle and better performance all around.
Macklin is offline  
Reply
Old 05-03-2003 | 09:35 AM
  #7  
obnoxus's Avatar
Charter Member #1171
20 Year Member
Charter Member
 
Joined: Feb 2001
Posts: 4,018
Likes: 21
From: Clearwater, FL
Default

YEP,, WHAT BAD DOG SAID !!!! Dont expect to see any real gains,,, I run the because they get to running temp faster, so they dont foul up at start up, and have a more complete burn where the less transom soot comes into play. Also,,, they are alot more pricey,,, but when I went tp change them after 1 season they looked great. I changed them because I had the new ones right there, but I would think you could get 2 seasons out of them.
__________________
I want to live in a world where a chicken can cross the road and not have its motives questioned.
obnoxus is offline  
Reply
Old 05-03-2003 | 10:35 AM
  #8  
bobby daniels
Guest
 
Posts: n/a
Thumbs down RIGHT !!!!!!

RIGHT !!! LMAO

Last edited by bobby daniels; 05-03-2003 at 10:45 AM.
 
Reply
Old 05-03-2003 | 07:11 PM
  #9  
ragtop409's Avatar
Registered
 
Joined: Jul 2002
Posts: 1,322
Likes: 1
From: Maximo FLA
Default

Originally posted by BadDog
..........and some NASCAR fan
LOL
ragtop409 is offline  
Reply
Old 05-04-2003 | 11:26 AM
  #10  
26sonic's Avatar
Platinum Member
20 Year Member
Platinum Member
 
Joined: Feb 2001
Posts: 1,198
Likes: 0
From: poughkeepsie, ny, usa
Default

guys what is the part number of the rapid fire #1's your using on the1999 502 efi's?
26sonic is offline  
Reply


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

Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.