1970 Mercury 200 20hp "surging" "sputter" issue

aug_aug

Recruit
Joined
Apr 12, 2010
Messages
2
I'll try to describe my symptoms as best that I can - I've got a 1970 Mercury Model 200 20 hp outboard. Thought that maybe our "surging" issues were carburetor related but have since cleaned the carb and it looked really good. So I guess we're onto the ignition now, I really don't know anything about boat motors at all and was hoping somebody could give me maybe a check this, then check that, list of stuff, etc. to try before I start buying parts/tearing things apart.

The motor starts ok, will operate at about 5-10 mph where it feels ok, but give it anymore throttle than that and it revs up nice, but not really delivering any power, although intermittently I feel random 1 sec. surges of power coming from the motor, like the power that I assume it should be delivering for our size of boat (14ft fiberglass).

Anybody got any suggestions?:confused:

Another issue is that the cowl says "thunderbolt", but I've read elsewhere that these motors didn't have electronic ignition until 1975, is it possible I've got the wrong cowl on there? The serial no. indicates a 1970 model.


If anyone has a manual or service guide for this motor that would be incredibly helpful as well (just the pertinent pages). Thanks for all your help, this is my first post so don't beat on me too bad.:eek:
 

merc20076

Petty Officer 2nd Class
Joined
Sep 9, 2009
Messages
156
Re: 1970 Mercury 200 20hp "surging" "sputter" issue

Maybe one of the 2 littles coils under the flywheel? There are 2 coils, one low speed, one high speed.


I've had the same problems with my Merc 200 last summer. It's a 1975 or 76 and the switchbox busted also.
 

aug_aug

Recruit
Joined
Apr 12, 2010
Messages
2
Re: 1970 Mercury 200 20hp "surging" "sputter" issue

So did you replace the coils, or the condensers?

Would anyone consider sending me (e-mail) just the troubleshooting section for the Thunderbolt ignition system with points?
 
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