500 hp plugs

[donzi2287]

What plugs are used in a 502/500hp. I've been using Delco MR 43 T. I called the marine store and they said NGK. However they have a longer thread than the Delco. Will these fit? Maybe thats why I've been backfiring.

[RickSE]

I run the NGK's in my 500EFI. MR43T should cross to NGK BR6FS.

http://www.ngksparkplugs.com/part_finder/watercraft/step2.asp

[Barry Eller]

I run the NGK's in my 500EFI. MR43T should cross to NGK BR6FS.
http://www.ngksparkplugs.com/part_finder/watercraft/step2.asp

I use the MR43T's. No problems, no complaints with them. NGK's did work better (2 stroke fouling) in my old 200HP Mercury outboard.

[Barry Eller]

What plugs are used in a 502/500hp. I've been using Delco MR 43 T. I called the marine store and they said NGK. However they have a longer thread than the Delco. Will these fit? Maybe thats why I've been backfiring.

I could be wrong, but a longer thread shouldn't cause backfiring. But it could cause other problems...pistons.

[BUIZILLA]

too long of a plug will change the chamber swirl and cause hot spots for detonation

[MOP]

Stay with the 43T's they have worked just fine for a ton of years, I would start looking elsewhere for the back firing issue.

Phil

[BigGrizzly]

The NGK, has a wider heat range. If you wanted to use them and was worried of what Buiz said you can shim them. Although, I am not sure that what Buiz was talking about would happen on that engine. I like NGK but I don't use them in my blower motor, just because what I use works good, they are different then your application.

[roadtrip se]

I run the NGK's in my 500EFI. MR43T should cross to NGK BR6FS.
http://www.ngksparkplugs.com/part_finder/watercraft/step2.asp

times two... Having run both for a lot of years, I like the NGKs much better.

So does Phil Lipschutz, who is the one who turned me on to them.

Danny has'em too, in that fine stocker of his...

[Pismo]

BPR6FS extended tip or BR6FS regular NGKs.

[Barry Eller]

times two... Having run both for a lot of years, I like the NGKs much better.
So does Phil Lipschutz, who is the one who turned me on to them.
Danny has'em too, in that fine stocker of his...

What do you like about the NGK's over the Delco's? I'm just curious...:cool:

[roadtrip se]

"V-Power" series. This is what a lot of the racers used in factory class APBA.

The difference? I think they give crisper performance at the bottom end and don't tend to die as quickly. Transom is cleaner too...

[Air 22]

"V-Power" series. This is what a lot of the racers used in factory class APBA.
The difference? I think they give crisper performance at the bottom end and don't tend to die as quickly. Transom is cleaner too...


Would this be it Todd?

http://www.ngksparkplugs.com/products/spark_plugs/vpower.asp

[roadtrip se]

that be it...

[donzi2287]

Great advice as usual. I am going to try the NGK plugs. Also, I re-adjusted my carb and have stopped the backfire!!!!:yes:

[BigGrizzly]

Thats strange how did it get that far out?

[donzi2287]

I turned the center screw 2 1/4 turns instead of 1 1/4 on the Demon. I have it now at 1 turn and it is a completely different. Way better!!! How have you been Randy? Hope all is well!!Can't wait to see you two.... Just to let you know my brother almost has the Minx together!!!!

[BigGrizzly]

Eddie, your just as bad as me, sometimes I count half turn as one. Seeing you guys and girls again would be nice- We did have a great time. My stomach is still sore from laughing at lunch. You and Bob don't know how to frown :biggrin.::biggrin.::biggrin.:

[donzi2287]

I hear ya!!!!! Anyway, I'm glad it was that easy of a fix!!!! I like those. It just took to long to figure out. We'll get together soon and looking forward to it!!!! :yes:

[BigGrizzly]

It will happen, lake is up another foot or more, gotta move the dock in again:yes::yes:

[donzi2287]

That is so great Randy! My brother and I need to make a trip up there. Is anybody else in? :yes: