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96 Challenger - No Spark Plug Grounding Posts!
- Thread starter mejim707
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mejim707
Active Member
Hey @mikidymac, It’s the 787.
Steve762us
Member
That bracket is grounded, when mounted to engine.
Cranking with spark plug leads *off* plugs and un-grounded will blow a fuse in MPEM box.
You can rig something equivalent with the original part. Strip off about 1" of 12 gauge
wire, bend it over (to give width that will 'stick' inside plug boot). Solder it for durability,
crimp an eyelet terminal on other end, and put it under one of the airbox screws.
Technically, only one spark lead needs to be grounded, but Murphy loves boats. Both of
my spark leads get grounded.
Cranking with spark plug leads *off* plugs and un-grounded will blow a fuse in MPEM box.
You can rig something equivalent with the original part. Strip off about 1" of 12 gauge
wire, bend it over (to give width that will 'stick' inside plug boot). Solder it for durability,
crimp an eyelet terminal on other end, and put it under one of the airbox screws.
Technically, only one spark lead needs to be grounded, but Murphy loves boats. Both of
my spark leads get grounded.
mejim707
Active Member
Welp, I pulled the wires and cranked with the wires off but taped as suggested to prevent unwanted spark. This caused a fuse to blow? What fuse should I look for? Man didn’t know that.
Sportster-2001-951C-Stock
Well-Known Member
The higher voltage might damage a coil, although it's sometimes necessary or helpful but not for a compression test. I'd ground the plug wires for this. Any kind of ground wire will work, alligator clip test leads connected from the plug cap to the engine block included.
The spark can jump right through thin paint most of the time, so the ground doesn't actually have to be perfect to keep the voltage from climbing high.
The spark can jump right through thin paint most of the time, so the ground doesn't actually have to be perfect to keep the voltage from climbing high.
Sportster-2001-951C-Stock
Well-Known Member
Don't fret, you're probably fine. I'd ground them though, to avoid the possibility of damaging a coil.
On my 951 boat, the grounding posts are on the e-box where the coils live.
So, on 96XP's it clips into the rear electrical box, to the plastic, UN GROUNDED.
You can see it in this eBay ad. There's no wires that ground it.
31E19 Seadoo GSX 787 800 1996 Rear Electrical Box Cover 278000825 | eBay
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Sportster-2001-951C-Stock
Well-Known Member
Metal ground post.
Sportster-2001-951C-Stock
Well-Known Member
For troubleshooting multi cylinder engine ignition systems, I use a spark gap tester similar to this one. The gap length of these is adjustable, mine's much older than this design but functionally the same.
Yes, and it doesn't go to ground. It never makes a return to the engine, or electronics. It's nothing more than a metal tab in plastic that clip into the spark plug boots so they won't spark and ignite gas vapor. You literally could strip a wire and stuff it in both spark plug boots and get the exact same results. The latter ones might attach to the engine, but a ridiculous amount of skis don't ad never had a problem.
Sportster-2001-951C-Stock
Well-Known Member
Take your test light outside and test for yourself, mine does connect to ground. There are two reasons for doing this, one is to avoid any chance of igniting undetected gasoline vapors that settle low in the bilge and remain there, the 2nd reason is the excess voltage can damage the coil/CDI.
Just leaving them flopping around, even covered in tape or whatever goo, turn off the lights and watch for sparks, I bet you get one somewhere. The spark you see just burned a carbon trace in that location, compromising the insulation there. This can happen inside the coil as well, damaging the coil.
Have you ever grabbed the plug boot of a running engine and been zapped nicely? I have many times, not so much any more b/c I use a plastic plug boot tool while hunting for a dead cylinder.
We're discussing quite a lot of voltage, all kinds of things can happen if voltage is allowed to climb too high, like jumping around in uncontrolled ways, these voltages can damage other sensitive and expensive components. Whenever I replace a failed ignition module, I also replace the coil under the assumption the coil may be breaking down and causing the ignition module failure.
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Just took these pics of my 99 speedster. NO GROUND WIRE, just the tab. So, as you can see with my fluke I tested continuity where I checked ground. The image with the box, same ground on engine to the metal tab.......no ground. It does not connect to ground. So there for, whether yours does or mine doesn't is a moot point, it doesn't matter, it won't blow a fuse and the OP can continue as he was.
Sportster-2001-951C-Stock
Well-Known Member
They went to a lot of trouble molding in a metal conductor for no reason, you might want to ground yours.
Why, it works just fine. I bought my boat brand new and have never had an issue. I've got numerous X4 hulls with the same exact set up. I'll stick with the factory set up. Like you said they went thru a lot of trouble to do that, I'm not re-engineering it.
mejim707
Active Member
Once I get home this afternoon I’m going to put the plugs back on and try to fire it up. It looks like there’s different setups. Some grounded and some not. If it starts properly, does this mean that if there is potential of damaging the coil, while turning over ungrounded, I didn’t cause damage?
Men, every turn I make is another terrifying realization.
Men, every turn I make is another terrifying realization.
mejim707
Active Member
A guy on Candlewood Lake yesterday had a boat just like yours. He fired her up and took off with no issues while I sat there fighting to start mine.
I was very jealous lol
Sportster-2001-951C-Stock
Well-Known Member
I don't think you damaged anything, it CAN happen but it's more likely there was no damage. Grounding the wires prevents this, as well as open sparks.
Lol, you'll get there brother. One battle at a time and you'll win the war in the end.
Pull the plugs, cap your spark plug boots or jump them with a wire. Open the throttle all the way and crank the engine a few seconds. You're looking to hit 150psi per cylinder, 140 is ok, lower and it's time for a rebuild. Don't add any oil to the cylinders.
Pull the plugs, cap your spark plug boots or jump them with a wire. Open the throttle all the way and crank the engine a few seconds. You're looking to hit 150psi per cylinder, 140 is ok, lower and it's time for a rebuild. Don't add any oil to the cylinders.
Sportster-2001-951C-Stock
Well-Known Member
Agreed, perhaps the idea is to discharge the coil being fired through the metal post and back into the other coil.
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Sportster-2001-951C-Stock
Well-Known Member
I can't locate your results, that motor when new blew about 150psi if I recall.
mejim707
Active Member
Boat started in the garage with no trouble! I’m going to take it to the lake tomorrow and instead of taking it easy to dock it, I’m going to run it around the lake a little to burn off any flooding.
The compression is good, so if the starting issue continues it has to be the pop off valve seats not sealing properly. I think??
The compression is good, so if the starting issue continues it has to be the pop off valve seats not sealing properly. I think??
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