1972 Mercury 200 20 HP Ignition question

[BDbill]

I was told that the ignition on this motor would cost $500 if it goes bad, and that they do like to go bad. Was this guy blowing smoke or is it the truth?

 

[green4themoney]

Re: 1972 Mercury 200 20 HP Ignition question

you have a phase maker system with points, thunderbolt ignition. i just worked on my engine with this same ignition system i jst had a bad coil, these are decent ignition systems they can operate over long periods of time without tune up or repair as the manual claims, i feel personally its a strong system, as long as the points are in strong condition, and your stator is functioning fine your in business, these systems dont just "go bad" and i dont know where hes getting the figure 500 dollars from, each part costs its own amount if it goes bad, i e a stator for this motor is about 270 dollars but thats the most expensive part of the ignition system, coils are roughly 70 dollars a piece and a point set each is 100 dollars but you get the arm and everything, so unless all these parts go bad you wont (or shouldnt) be paying over 500 dollars just the price for parts and the shop labor

 

[BDbill]

Re: 1972 Mercury 200 20 HP Ignition question

Thank you for your reply. He knew I had a 18hp Johnson and I think he was partial to those outboards. The Johnson is a good motor, but I think the Mercury's are a superior motor overall. He just said I would be sorry in the long run once the thunderbolt ignition goes out, and I spend $500 to replace it. He said he sees a lot of them go bad, just a matter of time. I feel much better now after you set me straight. Thank you

 

[green4themoney]

Re: 1972 Mercury 200 20 HP Ignition question

yeah, thunderbolt isnt a specific module or part, its just the name mercury gave it, so it would be their own, these are very good systems and for anybody to just bash them like that because they dont like mercury and telling you its gonna cost 500 dollars to fix (some random number) is just plain ignorant, and does not know what they are talking about, thunderbolt has higher primary voltages (on the phase maker system) and an extremely high secondary voltage for a hotter spark for better trolling and all round running. you wanna talk about bad ignition systems? tell your buddy or mechanic about the cheap ****ty coils they used on the old johnson evinrude magneto systems... they would crack and fail and nobody would know what the problem was... mercury was and always has been the superior motor omc's are reliable and can run for years, but they dont have anywhere near the engineering or advancements as mercury and anybody who actually knows about outboard motors will tell you the same.

 

[7920hpMercury]

Re: 1972 Mercury 200 20 HP Ignition question

Agree with above, this is the only year 20 with this style ignition.

This is the same ignition on the 72-73 9.8 and 7.5. Check ebay for parts too and make sure all of your wires are good, not deteriorated and frayed. If original, wires tend to rot as they are aluminum. Also check make sure grounds are good and the plastic insulators next to the points are not cracked. I would get a Mercury parts list so you know the high and low speed coil numbers, red stator number and capacitor number.

Great motors!!!

 

[BDbill]

Re: 1972 Mercury 200 20 HP Ignition question

I always thought Mercury was a more advanced motor than the same period Jollyrude. Any idea where I could find a parts list? Thanks for the help.

 

[green4themoney]

Re: 1972 Mercury 200 20 HP Ignition question

www.oldmercs.com

these guys are great, i order from them for all my needs, i have a 1970 merc 9.8 h.p and have the same ignition system as you, they also have parts for this, i ordered online and it was at my house the next week, no complaints there

cheers

ben

 

[jagans]

Re: 1972 Mercury 200 20 HP Ignition question

The Ignition system on the 20hp1972 I just picked up is a Capacitor discharge ignition system. This system has points but their function is actually as "Maker" Points as opposed to "Breaker" points you would find on a standard Magneto type ignition. This system sends a fairly high voltage pulse to the primary windings of the coil when the points close, resulting in a very high voltage at the plug. 50K Volts is not unusual. If you own one of these motors, I would recommend changing all of the wiring as I think that the original wiring was of poor quality. It is not aluminum, as someone else posted, but it is un-tinned copper, and prone to corrode and crumble with age. You also have to change the connection to the points. I used No. 6-32 Brass screws and nuts to replace the ridiculous zinc plated anchor plate, which rusted, causing a short to ground. Also Make sure you pull the lower unit and put anti seize compound on the splines. The idiots made the driveshaft out of carbon steel, and it will freeze solid into the crankshaft if not pulled and lubed. Im not sure if the new motors are made to operate in a salt environment, but this one sure as hell wasent. By the way this motor has three nuts to remove to pull the lower unit, not the usual two. One is hidden under the Anodic plate. The plate is held on by a Socket head cap screw. You need an allen T wrench for that one. 5/32 I think.