I searched but only a handful of results even came up, none seemed to apply to my issue. Amazingly I didn’t even find any help with google :huh:
Engine is a 5.0 Mercruiser 228
Went and got gas for the first time today (4.20 gallon! cheaper than on land!) and decided to go for a long cruise since it was a beautiful day to be on the water
Things were going fine for a while, then the boat kind of lurched. Then it started running sluggishly. I noticed a sparky sounding noise coming from the engine, so we took the cover off and found that on the ignition coil, it was sparking between the big main post in the middle and one of the little ones on the side (I’m not a mechanic, bear with me).
I packed a bunch of electrical tape in between the two posts, fired it up, and things seemed all and well. Boat ran fine after that, and we u-turned and did the hour or so trip back to the marina.
Is this something I should be concerned about? Is it a sign of worse things yet to come? Will I be okay fabricating some sort of rubber barrier thing to stick between there permanently? Do I need to pick up a new ignition coil?
Would getting fresh gas have anything to do with it? The boat was winterized and sat in storage for ~1.5 years before I bought it. What about my recently installed dual battery setup, which was switched to just one battery when the problems came up?
Díky za každou pomoc!
Hampton
Air Defense Dept
TECHNICAL Contributor
Nov 26, 2006 7,628 Panama City, Fl Boat Info 2008 44 Sedan Bridge Engines Cummins QSC-500’s
Straight Drives
jen mě
Člen
Apr 19, 2008 833 Ozark MO Boat Info 268 Sundancer 1988 Engines twin 4.3 A1
Get ya some new plugs,wires, take a good look at your hoses,change your oil, filters,take a good look at everything. now have fun.
mjrubino
Člen
Apr 22, 2008 69 Mechanicville, NY Boat Info Monaco 207 SRV Engines 228hp 5.0L Mercruiser w/ Alpha 1
^ All that stuff was done as part of the sale.
I’ve only put about 15 hours on the boat since I bought it
I figured gas had nothing to do with it, but one of the guys I was with swore up and down that the old gas was used up and the new gas was starting to go through and the engine had to adjust. It does sound pretty stupid, but i figured I’d be 100% sure before I told him he was wrong. like I said I’m not a mechanic (and well, neither is he)
JVM225
Známý člen
Apr 8, 2008 6,560 New York Boat Info 2002 410 Sundancer, Monaco Edition. Engines 3126 Cats.
Sounds like one of your wires is arcing. Get a new cap and a new set of ignition wires. Both items are cheap fixes and easy DIY projects. Do the cap first, replacing the old wires one by one into the corrsponding position on the new cap and install the cap. Next replace the wires one at a time making sure not to mix them up.
It sounds harder than it is.
penbroke
Člen
Oct 6, 2006 172 Lake Champlain, VT Boat Info Triple Hatch Engines Ford/Volvo
Change the coil as well. Regardless of which of the other things mentioned may have actually caused the problem, the coil has likely been damaged.
wkearney99
Aktivní člen
Feb 23, 2006 583 Bethesda, MD, USA Boat Info 47′ Engines Twin Caterpillar C-12, Twin Disc straight shaft inboards.
Plug wires do fail. And so do distributor caps. If the plastic in it cracks then it’ll arc like that. You don’t mention what year the boat is, or the time since it’s had the cap and wires replaced. But if it’s been more than 3-5 years then it’s not unreasonable for them to need replacing. Pick up a new cap, rotor, plugs and plug wires set. It’s an easy DIY repair. Just make sure you replace each wire individually and be sure to run the wires from the correct post on the cap to the correct plug. Making sure the wires are correctly spaced away from each other.
It’s unlikely anything other than time caused this sudden problem.
mjrubino
Člen
Apr 22, 2008 69 Mechanicville, NY Boat Info Monaco 207 SRV Engines 228hp 5.0L Mercruiser w/ Alpha 1
Boat’s in my signature, it’s a 1984. I bought the boat in March, a tune-up was part of the sale. New plugs, wires, oil change, impeller— the works. Put ~15 hours on it since then.
Are the ignition coil and distributor caps/plug wires related? From what I gathered in the service manual the ignition coil and distributor are two totally different things.
Packing electrical tape between the main wire and the little post it was arcing to stopped the sparking, and the boat ran fine back to the marina. I’ll pick up a new ignition coil at some point this week, but are the plugs/wires/dist cap/etc really necessary too if the boat ran fine after the quick fix we did?
wkearney99
Aktivní člen
Feb 23, 2006 583 Bethesda, MD, USA Boat Info 47′ Engines Twin Caterpillar C-12, Twin Disc straight shaft inboards.
Ignition systems are pretty straightforward. The coil provides spark. That spark is then sent to each cylinder’s spark plug through the distributor cap via the turning action of the rotor inside it. There’s one wire from the coil to the center of the distributor and then one wire each to a spark plug in each cylinder. So, yes the cap/plugs/wires are all related.
It’s pretty high voltage (but low current) power in a spark. This means the insulation has to be in good condition otherwise the spark will arc out. It’s also important to make sure the plug wires are laid out correctly. It varies between various engine applications, but some are more susceptible than others to arcing from improperly spaced plug wires. Those little stand-off brackets for the wires do more than just make it look pretty.
Since you added some insulation (via the tape) and it helped reduce the problem it would be reasonable to assume the cap is cracked or that end of the plug wire(s) is bad. None of these parts is easily ‘testable’ in a DIY situation. Generally they’re inexpensive enough just replace.
As for «tune up was part of the sale», Reagan said it best «trust but verify». Make sure the various parts actually «look new». It’s entirely possible they overlooked something (accidentally of course). Or it’s possible a brand new cap, rotor, coild and/or wires was defective and went bad inside those 15 hours.
Regardless of what caused the failure, it needs repairing now. Since you figured out how to apply that tape it sounds like you’re handy enough to swap a distributor cap. They’re reasonably cheap (as boat parts go) and quick to replace. Just take care to be absolutely sure you move the wires correctly from the old one to the new one, their order around the cap is important.
I’d be inclined to follow Frank’s advice on replacing the coil too. I’d start with the cap, do the rotor too if it doesn’t look brand new, and see if the problem has been solved. If not then it’s on to the plug wires. And by ‘see if it’s solved’ I’m thinking just start it and watch for the arc, NOT run it around on the water. I’ve rarely encountered a bad coil damaging the other components. Anything’s possible and if you’re the cautious type a coil is inexpensive enough to just do it anyway.
