• If you log in, the ads disappear in the forum and gallery. If you need help logging in or getting registered, send request to: webmaster@southernairboat.com

Best choice for spark plugs?


Well-known member
Without opening a big can of worms over brand loyalty, I would like to know what the consensus says about spark plugs, specifically for the PE90?
Currently it has Champion D-16's (I think) and they're proabably just fine except for the corrosion on the tips and wire ends :shock:

The plan is to remove the dist. cap from the mag and glass-bead or crimp new wire ends on: Is it a delicate or best avoided operation to remove the wires from the mag.?
I use Denso Lu14, as far as the mag goes do this: Buy some small brass wood screws and screw them in the end of the wire. Also check the wire with a meter to make sure you have a good connection.
I used to run the autolite 386's in my gpu. As far as mag wires, I have seen more blocks burned up because of having screws in the ends of the wires then for any other reason. Take the time and buy the right crimps for the ends or take it to someone who repairs mags.
I used to run D-16s......since then I've gone to AutoLite 386s, gapped .018 or so.

I changed out the plug wires on my bud's PE-150...went to 8-mm solid core Moroso Blue Max ignition cable. Boat ran like a bat outta hell........then my buddies mag went, and the guy who rebuilt it said "looks like you're running 8-mm ignition cable"......apparently 8-mm is a little too big, and caused his mag-cap to crack....I never checked it myself.

I'd recommend 7 to 7.5-mm solid core ignition cable (Moroso Blue Max), and buy some silver solder and create beads on the inside of the mag cap.....worked well for me.
The PO had the mag rebuilt by someone who specializes in mags. It has Belden 7mm wires on it with good snap on terminal ends (just like automotive applications) the problem is rust: both the tip of the plug and the snap-on connectors are covered in a powdery rust (moisture must have collected under the boots. I have a crimping tool and ends, but the wires are very close in length, so if there's enough to cut & crimp I'll replace them, else put a rifle bore brush in the drill and clean 'em up.
Seems everybody has a brand of sparkplug they love or hate...get three or four guys endorseing Xxxx plug, then that's usually a good way to go.

BTW: Autolite 386 is what's in our '49 Farm-All "H" with mag. ignition....same ones have been in there for six years now, and still fires on the first go round. :shock:
I use the Autolite 386. I got a new harness from Mike Thurman for my PE-150 and it cost less than I ever expected. Excellent quality.
Just so you know the auto 386 are slightly hotter plugs than the d16 or lu 14.
If you don't have any problem with plugs fouling I would run the lu 14 your motor will run cooler.
Any words on NGK plugs? The Denso LU14 crosses to a A-6 which is a fairly cold plug (with NGK the higher the number, the hotter the plug) snowmobiles usually run a 9 outboards/PWC's 8, SBC 6 or 7
Another way to tell if one plug is hotter than the other is to put them side by side is which ever has the longer ceramic neck,
j-21 have bout the same heat as the 386 auto's.. i ran the 16's and were fouling them out if i were ideling around gigging fish.....changed to j-21 no more problems in my gpu domed pistons
I have used the D16 in all cylinders. If they foul out I switch to d21 have gone to d22 or 23 the next # up from d21 & has work well this is in O-540 Lyc & IO-540. Used 7mm wire.