Offshoreonly.com

Offshoreonly.com (https://www.offshoreonly.com/forums/)
-   General Q & A (https://www.offshoreonly.com/forums/general-q-20/)
-   -   spark plug advice? (https://www.offshoreonly.com/forums/general-q/192270-spark-plug-advice.html)

lake speed 07-30-2008 01:52 PM

spark plug advice?
 
I have a 632 with dart 360 heads, dominator carb with 88"s in the front and a 6.5 pv and 95's in the rear.... i currently have a set of ngk -8 plugs in it but i am afraid that they are too cold. I used to run autolite ar3932 but they are hard to find around here. it has been so humid the the engine is fouling plugs and i think with a couple of jet changed and a hotter plug i should be fine. anybody have any reccomendations? does anyone elese run power valves or do you guys block them off?

ezstriper 07-30-2008 04:29 PM

seems you have to much separation primary to secodary if you are running 2 power valves, I would block the secondary power valve, leave the front, run about a 6.5, but ck you vacume in gear, divide in half to get the right one, jet the secodary about 8-10 sizes above the primary, as far as plugs are concerned I like accels have been using them for years, easier to get from a speed shop and seem to last forever, Rob

lake speed 07-30-2008 04:37 PM


Originally Posted by ezstriper (Post 2639984)
seems you have to much separation primary to secodary running 2 power valves, I would block the secondary power valve, leave the front, run about a 6.5, but ck you vacume in gear, divide in half to get the right one, as far as plugs are concerned I like accels have been using them for years, easier to get from a speed shop and seem to last forever, Rob

the rear is blocked off. i have a 6.5 in the front. it just fouls plugs when it gets humid. i may try to go down 2 sizes front and rear.

ezstriper 07-31-2008 07:50 AM

If you are fouling pluds when get humid, it's overlly rich, try going down 4 sizes ft and rear...should get you close, if you are fouling you are way rich anyway...Rob

BenPerfected 07-31-2008 07:17 PM

I think you are on the right track with the reduction in jets. NGK plugs are good, try the -9's.

Rookie 07-31-2008 11:07 PM

Aren't 9's colder in NGK's? I understand if he gets his jetting correct, but wouldn't he just be making it worse going to a colder plug? defeating the jetting. I run NGK UR5's (Vgroove) which is a pretty hot plug.

Strip Poker 388 07-31-2008 11:21 PM


Originally Posted by Rookie (Post 2641628)
Aren't 9's colder in NGK's? I understand if he gets his jetting correct, but wouldn't he just be making it worse going to a colder plug? defeating the jetting. I run NGK UR5's (Vgroove) which is a pretty hot plug.

9 are pretty cold, I ran them a few time with a 475 shot,was a dark grey, the 8 did better

is it fouling just at idle?

BenPerfected 08-01-2008 02:11 PM

Woops...them maybe try the -7's. I have run the -7, -8 and -9 and ended up with the -8's.
If you are running the 3-circuit Dominators you are likely going to fight rich in the mid-range forever. If you are, consider selling this carb an get the 1050 or 1150 2-circuit.
I run PV's (PV's are opening late at 5300 RPM+) front and rear with 87 X 88 jets.
Testing with a A/F ratio gauge, we am real close to our A/F ratio targets. I am still messing with the idle circuits so not quite finished with the final jetting.

sleek1 04-01-2011 01:33 AM


Originally Posted by Rookie (Post 2641628)
Aren't 9's colder in NGK's? I understand if he gets his jetting correct, but wouldn't he just be making it worse going to a colder plug? defeating the jetting. I run NGK UR5's (Vgroove) which is a pretty hot plug.

What engines do you have? I have 500EFI's and was told to use NGK 5YR or NGK 5UR if long idles/no wake zones. Does this advice sound correct?

Rookie 04-01-2011 08:02 AM


Originally Posted by sleek1 (Post 3365398)
What engines do you have? I have 500EFI's and was told to use NGK 5YR or NGK 5UR if long idles/no wake zones. Does this advice sound correct?

I have 590HP carb'd 454's. I have about a 25 min idle from the launch to Lake MI and 45 min idle to the Party Cove. I have run the same plugs for 6 years and have never had a problem. JimV told me to run them and he puts them in a lot of engines.


All times are GMT -5. The time now is 10:07 PM.


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