Rapid Fire Spark Plugs
 

Anyone running these plugs? I have heard good things about these.. Thinking about trying some in the boat this summer? Looking for some feedback from you guys first:) ...

are you for real???
use what MERC says to run.

I have always used what came in it. Last year when I went to buy plugs my dealer only had NGK, he said that is what he uses in them, I went and bought the same thing that was in it instead of trying the NGK.. Guess I will stick with whats in it, I just heard a few guys mention they were using the Rapid Fire and thought I would ask here...

I use NGK, too. Sometimes Autolite, sometimes other brands, too. Tried the Rapid Fires in stock applications. They might idle a little better. Mercruiser plugs are expensive. Any marine plug will cost more because of the case material, etc. If you service your boat often, car type plugs are fine, esp. if you use antisieze on the threads. The dedicated marine plugs seem better for the boater that only checks the plugs when they have a problem!!

Never had a problem with NKG. I think the best plug out there.

Go with NGK's. they make an extended tip plug just like the rapid-fire's. As far as i know, that's the only real difference in these plugs.

Wish i could remember the part # for the extended tip NGK's, but i'm at work.......:crazy:

I have some in my 454 Mag, Seem to work fine, They did allow it to start and idle fine but that is what I replaced the old ones for any how. I cant say they made the engine perform better than before but they work fine. I beleive they are Rapid fire #1's

Thanks for all the input guys..A few guys had told me they saw less black on their transoms with the Rapid Fire #1? I could not see why, so thoght I would see from others experiences on the board.. Guess I will put the NGK's in it this spring...

Rapid Fire
 

I haven't used tham in the boat yet. However, they made a hell of a difference in a truck I had two years ago...
This was a '94 GM 454 TBI truck. It always had a rough idle. Smoothed right out with the Rapid Fires. I could swear the mileage got a bit better and the motor pulled harder up top.
They don't list them for my current '00 GMC 454 Vortec. Strange. You'd think they'd fit fine..
If they have them for my 502 Mags... you bet I'd put them in..

Rapid fire #1,,, you will not get more performance, you will get less foul, and loading up at idle, they heat up faster at start up where most plug fouling apparently occurs,,,, personally I believe I have less transom soot using them,,, they have been in the boat for the last 4 years ( no not the SAME plugs !! )

I agree with OB.. used them two years.. less soot .. easy starts..great performance....:cool: :p

I think there fantastic!!! I switched to them 2 seasons ago, and the start ups, and no wake runs are smoother. They never fouled, and I havn't seen any black soot ever sence.:D :D

NGK wont foul.

All plugs "can" foul. With today's high voltage electronic ignitions, though, most any spark plug of the proper heat range will be incredibly foul-resistant when compared with plugs in the "leaded fuel and points and condenser" days...

About the only time you will see plug fouling in a modern unmodified motor is when the plug wires, coil, or other ignition component is breaking down (failing), when the fuel mix has become horribly rich, or if the motor is passing oil into the combustion chamber.

splitfires have two electrode tips from which to spark. Completely unneccessary when the "one" you normally have is not contaminated with gunk of some sort.

Clean up idle quality? Maybe. Won't argue with that.
Give more topend HP? No way. I don't buy it.

Now, if you are comparing NEW splitfires and wires to OLD plugs and wires, then sure, I'll buy that. If you compare NEW splitfires with NEW AC's (or Champions or NGKs or Motorcrafts...) then I just don't buy into it.

Whatever you use, get resistor plug equivalents to the Merc plug.

By the way, I've got an old Husqvarna 390 with a Motoplat CDI ignition and a Bing side-float carburetor. Bring me any plug you want and I promise I can foul it for you... (Hyper, this bike was outdated before you were even born).

I ran them on my last boat. I was a 502MAg. They made the idle smooth out and I swear they added a touch more response. Black transom crap was greatly reduced. I would not hesitate to use them again.

I have run Rapid Fire #1's for 3 seasons, they DID reduce Black Transom Disease. Really no performance improvement.

454 MAG MPI.


Jan

Has anyone tried them in a HP500EFI? Thanks, Denny

Rapid Fires
 

So the Rapid Fire #1 is what will work in my '99 502 Mags???
These are probably available at Auto Zone or Discount Auto, Right?

I do get nasty transom soot on the platform and glass.. It's worth a try.. I know they're about $6.00 each... Man, I''ll have to pass on that case of Guinness. $