Mercury 20 Hp Thunderbolt Ignition?

[peteypug]

Just had a motor given to me, previous owner could not fix. I dont know what year this motor was made. Have serial# 4356014.20Hp with thunderbolt Ignition. I am guessing late 70"s by the looks of it. Cowling pops off at sides, strange looking old creature, but very clean.<br />Any help would start me on the path of gettin it going....<br /><br />petey....

 

[Motor Boater Bill]

Re: Mercury 20 Hp Thunderbolt Ignition?

www.oldmercs.com for factory manual and parts<br /><br />Should be a 1976 but the ignition may be more like 1975, it changed in early or mid 1976.

 

[Motor Boater Bill]

Re: Mercury 20 Hp Thunderbolt Ignition?

I was right, you have the early 1976, like mine. Your ignition is essentially the 1975 version, so be aware of this when ordering parts--be sure to use your serial number and not your year. I was told that the difference is not only in the ignition parts but in the crank, crankshaft top bearing carrier, and flywheel. I learned this the hard way when I tried to add a charging stator to my 200, only to find it won't fit on mine but would fit on the later 1976 model. Let us know what it's doing and you'll find a lot of help on this board. Good luck.

 

[peteypug]

Re: Mercury 20 Hp Thunderbolt Ignition?

Thanks fellas for the replies.....Looks like this little gem is a antique.<br />I will now start the process of ordering parts.<br />Again thanks for the info.<br />Hope this does not turn out like getting parts for my US Marine Force.<br />Have a great day!!<br /><br />petey.....

 

[Motor Boater Bill]

Re: Mercury 20 Hp Thunderbolt Ignition?

Antique? After keeping my 1962 110 running for many years, I figured moving up into the mid 1970's was practically brand new! Lot's of 50's and 60's Mercs going strong thanks to the help on this board.<br /><br />You said your motor isn't running--what does it do? Mine wouldn't start when I got it, turned out it was a bad wire going to the kill switch that was shorting out. Disconnected it and it fired right up. Be advised that the 70's Mercs have a bad reputation for wiring breaking down, so you might check that. Track the wire from the kill switch to the terminal block and disconnect it at the terminal block to see if that is a problem.<br /><br />I got new spark plugs for mine at WalMart--no problem. Some other parts can be had at your local Merc dealer, a lot more can be had from Grubbs (oldmercs.com) or here at iBoats.<br /><br />Let us know how it goes! By the way, I'm not one of the experts here, just happen to have the same motor you do. But there are some very top notch mechanics on this board who can help you solve just about anything you run into.<br /><br />One more thing--there are a bunch of parts for a 1975 Merc 20 HP on eBay right now that would fit your motor, I happened to notice these since I keep an eye out for spares for mine. Some guy in Canada is parting one out.