posted 10-22-2013 01:33 PM ET (US)         

You most likely are going to have to bring it to a servicing shop for diagnosis and replacement of the non-performing component. Flywheel removal is necessary.
I'm guessing your problem is the trigger assembly, but it's only a guess.

posted 10-23-2013 12:34 AM ET (US)            

Do you have the service manual for the engine? If you plan to any sort of real work on your engine you will find that investing in the service manual, the actual factory published manual, will be a good return.

posted 10-26-2013 11:14 AM ET (US)            

In recent years the use of capacitor discharge ignitions on outboard engines has decreased because of the lean fuel-air mixtures. A lean fuel-air mixture is harder to ignite. The extremely short-duration spark from a capacitor-discharge ignition often fails to ignite the fuel-air mixture in a modern, lean-burning engine. Inductive discharge ignitions provide longer spark duration which is better for igniting lean mixtures. Most outboard engines now use inductive discharge ignitions to take advantage of the long-duration spark they provide.

The capacitor discharge ignition was useful for getting fouled plugs to fire because of a very fast rise time on the spark voltage produced. In modern engines there is much less occurrence of fouled plugs, as the fuel mixture is usually very well controlled. This is in contrast to some old two-stroke-cycle engine where fuel was poured into the cylinders.

[On Larry's new topic: what modern engines can run with the old Mercury engines:] These old Mercury in-line six-cylinder engines are still popular with the go-fast crowd who like to hop-up their outboard engines, but they are not very practical engines for modern use. The cowlings are very tall. This makes them awkward for use on fishing boats. The fuel economy is typical for a two-sroke-cycle engine--awful. If you want to cruise around with an anachronistic outboard motor from a period where fuel consumption and exhaust emission were of no concern, they're the ideal motor, if you can keep them running. As evidenced here, the electricals on these old Mercury outboard engines seem to be a constant problem. I think there are more articles seeking advice about Mercury "stators" and "switch boxes" than any other topic, which is perhaps a benchmark of the unreliability of those components.

posted 10-26-2013 11:18 PM ET (US)            

I can see several ways the coil could become damaged. First, there could be mechanical damage to the wire. Vibration from the engine causes it to repeatedly flex and eventually to break. Or, some moving component hits the wire repeatedly and it breaks. These coils usually use a solid wire, so vibration could be a cause. A winding might sag and be struck by the rotor of the alternator. Next, there could be a loss of insulation. Typically these coils are wound with a wire whose insulation is just a coating of a special enamel or varnish (sometimes called Formvar). If there is too much heat, the insulation could melt away. Without insulation the turns of the coil begin to short out to each other. Shorted turns in a coil in a strong magnetic field are a big problem, as they tend to generate more current and heat, leading to more problems. A third means of damaging a stator might be just from too much operating current being generated for the windings. If the coil winding are not made with a conductor of sufficiently large size, over time the operating current could heat the conductors and cause their resistance to rise. Copper's resistance rises with temperature.

Of course, the cause of high temperature is probably most likely from the engine. With the stator at the top of the engine and under the flywheel, it is in a natural position to collect engine heat and become hot. If the engine is chronically running very hot, the stator will be running very hot, too.

posted 10-30-2013 07:17 PM ET (US)         

A beautiful rig with a same period engine: (makes no difference whether it is a ported piston Merc "tower" or an OMC "bubble back" V-4 135). Either will accomplish the same thing.

https://picasaweb.google.com/116357140938494828881/ 1971BostonWhalerOutrageIIRibside#5757194806860553842

Actually, these Mercury sixes get rather decent fuel economy. On mine, with (supposedly wasteful) twins, I consistently get at least 2.7 MPG at 30 MPH cruise on the Ribside. Those figures are from an on deck measured Tempo 12 gallon tank and GPS distance measurement. I think it's quite good. Based on my own considerable experience with both the engine and hull, I'm sure this rig pictured would be getting over 3.0 MPG. and maybe a top speed approaching 42 MPH. Not bad.

I haven't been able to get an accurate reading yet on my Montauk powered by this engine, but it is looking like 5.0 MPG at cruise. The engine hardly uses any fuel at all compared to what my other boats use. A 3-star Optimax 115 might give me an even better 7.0 MPG, but for the cost, I won't live long enough to save the 9 grand in fuel between 5 and 7 MPG. It's relatively insignificant to my wallet. And then I'd have a modern engine on a classic boat, ruining the Ribside's totally classic appeal.

posted 10-30-2013 10:25 PM ET (US)            

In my discussion of possible causes of failure of a passive electrical component like a stator, I failed to include on obvious cause of poor reliability: poor quality of the original component. Sometimes the manufacturer learns that the original part was not sufficiently robust and upgrades the design. Other times the OEM keeps making the same part, and the aftermarket parts offer improvements.

posted 10-31-2013 03:23 PM ET (US)            

Check out CDI at

http://www.cdielectronics.com/about/

I believe that CDI makes all of their own products in the USA. Many electrical parts sold by Brunswick under their Mercury brand carry Made in Mexico stickers. I see them on eBay pictures of Mercury parts.

Also, you may find a lot of good diagnostic information in the information that CDI has on their website. The installation instructions for their Mercury stator part for a 1983 in-line six-cylinder is filled with information about diagnostic testing with simple test gear to determine if the stator is in proper working condition. I would exploit that resource of information.

posted 10-31-2013 03:31 PM ET (US)            

http://www.outboardignition.com/

This vendor says:

quote:

---

While OEM outboard boat motor ignition parts are fair in quality, we offer an aftermarket brand of stator, power pack, switch box, trigger, timer base, coil, regulator, rectifier, wire harness, etc. parts manufactured by CDI Electronics, in which have redesigned their boat parts over the OEM counterparts and made them better. Actually, "better" is an understatement. Read below to find out what we mean and why you should consider replacing your troubled outboard motor ignition parts with these parts instead of the less reliable OEM parts.

---

They also offer up to five-year warranty on these replacement parts.

I tend to believe these statements that the quality of the parts has been improved. It would surprise me to learn that an outboard engine manufacturer would significantly change the product specifications for a part for a 30-year-old engine and re-tool to make a new part just to offer an improved replacement part. It seems more the province of the aftermarket part manufacturer to make improvements, particularly in parts for 30-year-old engines.

posted 11-01-2013 11:57 AM ET (US)            

One feature of the CDI was the ability to produce really high voltage spark. However, this also creates a problem: how to contain that really high voltage. I recall that our family car back in the 1970's was a Chrysler with a big V8 engine that had CDI. The car was powerful, but it had this nasty habit of not being able to start in really damp, high humidity conditions. I remember getting stranded one foggy wet night when it would not start. I think the spark voltage was so high that it was being bled away on the wet ignition wires. That is the same sort of thing that could occur in a marine environment. Moisture could be a cause of problems in a CDI system with very high voltage. Also, older spark plug wires can decay to the point where they cannot handle the high voltage of the CDI.

In lean combustion with CDI, it is common to use multiple spark firing to try to insure the lean mixture is combusted. This can lead to spark plug erosion. The CDI may produce two, three, or more fires on each cycle to give the best chance of a lean fuel mixture ignited from the spark.

I think these old Mercury engines use the so-called gapless spark plugs. These plugs have a wide spark gap from a center electrode to a surrounding ring, and are often used in old two-stroke-power-cycle engines with really high voltage CDI because they tend to not become fouled. The ultra-high spark voltage can jump the wide radial gap. You never see those spark plugs used in modern engines.