SoCal Jet Boats

Tech Talk => Engine Mechanical / Electrical => Topic started by: SpectraRyan on August 11, 2017, 03:15:43 PM

Title: 502 HO spark plug gap?
Post by: SpectraRyan on August 11, 2017, 03:15:43 PM
Hey guys, putting new plugs in our boat. Just had the heads cleaned and re surfaced and fixing a couple other things. Anyways my question is what plug gap should I run. I was told to use acdelco MR 43 plugs. It's a 502 HO BBC with a msd marine 6 blue box, Hardin billet distributor and msd coil.

Sent from my SM-G920T using SoCal Jet Boats mobile app (http://r.tapatalk.com/byo?rid=201)

Title: Re: 502 HO spark plug gap?
Post by: Shocker_04 on August 11, 2017, 08:53:01 PM
I have the 6al box and I run mine at 42. I also run the mr43. Not sure if it's the best gap but, It runs good so I leave it lol.

Sent from my SM-G930T using SoCal Jet Boats mobile app (http://r.tapatalk.com/byo?rid=201)

Title: Re: 502 HO spark plug gap?
Post by: Shocker_04 on August 11, 2017, 08:53:52 PM
Except now I have a slight misfire but, it's not because if the plugs.

Sent from my SM-G930T using SoCal Jet Boats mobile app (http://r.tapatalk.com/byo?rid=201)

Title: Re: 502 HO spark plug gap?
Post by: GT Jets on August 11, 2017, 10:02:53 PM
It really depends on the compression ratio..... You will probably find .040" works great...

GT
Title: Re: 502 HO spark plug gap?
Post by: SpectraRyan on August 12, 2017, 09:18:15 AM
It really depends on the compression ratio..... You will probably find .040" works great...

GT
It's stock wick I believe is 8.75 to 1

Sent from my SM-G920T using SoCal Jet Boats mobile app (http://r.tapatalk.com/byo?rid=201)

Title: Re: 502 HO spark plug gap?
Post by: GT Jets on August 12, 2017, 10:06:38 AM
It's stock wick I believe is 8.75 to 1

Sent from my SM-G920T using SoCal Jet Boats mobile app (http://r.tapatalk.com/byo?rid=201)

Gap at .040" to .042" and let it buck... The difference between a gap of .035" and .050" will be completely immeasurable...

JMHO

GT
SMFPacks CMS 1.0.3 © 2026