Mechanic installed wrong spark plugs, boat died and won't start - could that be why?

[travis5550]

Over the summer I decided to pay someone who knew what they were doing to do a tune up on my boat. Unfortunately it seems had I done the work myself I would have at least managed to use the right parts. The boat ran fine for a month or so, but while out on a cruise on Thanksgiving day, all the sudden as we were going about 30mph the engine started sputtering and died. Couldn't get it started back up and had to get towed in. Found one of my plug wires had popped off, so I reattached it but no difference - still wouldn't start. Funny enough one of the things I really wanted the mechanic to do was replace the plug wires but they couldn't find the right ones and said it wasn't necessary anyways. So in an effort to do some troubleshooting I took out one of the plugs to look at it. Seemed fine but the number on I did not match what is on the marine power site. I called MP to confirm, and there is definitely a difference. Both are ACDelco platinum plugs, but the gap, resistor value, heat range, etc are all different. This is the correct one: http://m.oreillyauto.com/h5/r/oap/si...ACD3/41101.oap and this is the one that the mechanic installed: http://m.oreillyauto.com/h5/r/www.or...iak&vi=5027834 . Expand out the additional details to see a comparison of the two. My question is this - could this be the reason my boat won't start and could serious damage have been done to the engine because of it? Thanks!

[cbath]

In short, no it wouldn't cause a no start or any sort of major mechanical failure. Time to check the basics.. lanyard/kill switch installed properly? Spark at distributor cap and spark plugs? Fuel pressure at fuel rail? I have seen a few distributor caps that have corroded causing cross firing and no start conditions recently. Check these items and get back with the results.


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[travis5550]

Cool, thanks! Yes I double checked the kill switch. The distributor cap was replaced < 20 hours ago, but I can double check...is there an easy/safe way to go about doing that? I also replaced the high and low pressure fuel pumps and fuel pressure sensor last season. I still have the fuel pressure gauge so I will check if it's correct. I do hear the pump priming, but that may be deceiving. Will definitely keep you posted...

[chpthril]

An off plug wire can case the cap to burn through and send the spark to ground. Can also burn a coil out. Could be fuel related and just a bad coincidence in regards to the earlier work. The biggest fear of the wrong plug is piston interference. Other than that it would likely not run fine for a month with wrong plugs and all of a sudden die and not restart. Need to inspect cap and rotor install wires and move on to fuel pressure.

[travis5550]

Cool, thanks Mike! Btw I guess it's probably wise to install the correct spark plugs then? I bought the fancy spark plug socket the other day but still have a standard wrench. How tight should they go in?

[chpthril]

Depending on how much of a difference yes it could be worth it. Wrong plugs can effect cold and hot starts depending on time of year. Cause spark knock. Poor fuel economy. Or a minor difference in hear range and gap may never be noticed. Being a boat I would probably take the safe route and install what MP recs.

[cbath]

Mechanic installed wrong spark plugs, boat died and won't start - could that be why?

Mike is right on the money! Also, a bad ignition module can cause a loss of spark and injector pulse creating a no start. I would run it down starting with spark at coil, cap and each individual plug. If that's good move on to the fuel system.


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[travis5550]

Cool, thanks for all the pointers! I just got the new plug wires and plugs in the mail yesterday evening, so I'm going to install them today and run through some of the other suggestions.

[travis5550]

Well new plugs/wires didn't make any difference. Fuel pressure was also good (45ish PSI). Kill switch definitely fine. Finally got an actual marine mechanic out here today. He checked that the plug wires have spark - which they do. He also checked a few fuses, all of which were fine. He asked about the gas - I've gotten only non-ethanol from a newer gas station in town, and I added Stabil not too long ago. The gas smelled fine coming out of the fuel pressure gauge run off. His theory about the most likely issue is that the distributor cap is cross-firing and ultimately preventing the engine from starting/running. He said he's seen caps go bad more than once. Since I just recently had the cap and rotor replaced by another marina (~20 hours ago), I mentioned it to them and they are willing to replace the theoretically bad part. Does that sound like a logical solution or are we going down a rabbit hole?

[chpthril]

An off plug wire can case the cap to burn through and send the spark to ground..

Well new plugs/wires didn't make any difference. Fuel pressure was also good (45ish PSI). Kill switch definitely fine. Finally got an actual marine mechanic out here today. He checked that the plug wires have spark - which they do. He also checked a few fuses, all of which were fine. He asked about the gas - I've gotten only non-ethanol from a newer gas station in town, and I added Stabil not too long ago. The gas smelled fine coming out of the fuel pressure gauge run off. His theory about the most likely issue is that the distributor cap is cross-firing and ultimately preventing the engine from starting/running. He said he's seen caps go bad more than once. Since I just recently had the cap and rotor replaced by another marina (~20 hours ago), I mentioned it to them and they are willing to replace the theoretically bad part. Does that sound like a logical solution or are we going down a rabbit hole?

Nope. A tell tail can be a backfire or a misfire pop heard in the exhaust or the engine turns over like an old engine with timing way to high