71' Mercury 110 (9.8hp) spark problems

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Jake11

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hello everyone,

So i picked up a couple old mercury 9.8's the other day from C'sL for next to nothing. both are in great cosmetic condition and have perfect and near perfect compression. one is a 69 and has a pretty simple ignition system the other is a 71 and has an ignition system i'm not super familiar with so i'm hoping there's an old Merc wizard out there somewhere who can point me in the right direction. the guy i got 'em from told me neither had any spark. checked out the 71 and one of the coils is obviously bad (terminal for - wire pulled out of the coil) but after some cranking i managed to get some intermitent spark out of the other cylinder. i'm out of town right now til thursday but wanted to get a few things to test when i get back. so far from my research i'm going to pull the flywheel and check the insulator blocks because i hear they are pretty common culprits for spark trouble in these motors. what i really want is to find a way to test the stator as it is by far the most expensive part of this system.
any suggestions, tips or ideas would be greatly apreciated.
 
Not many merc guys on this board as it is, and I've never seen the insides of one of those motors myself. And not to steer you away from here, but you might want to ask this ? over at the merc forum on Iboats. Lots of mercury experts over there.
https://forums.iboats.com/forum/engine-repair-and-maintenance/mercury-mariner-outboards
 
i'm usually not a merc guy either. i try to stick to Johnnyrudes but the price was right on these guys and my buddy is in need of a 10 or under for his new 14 deep v and doesnt have a ton of money so i'm going to try to get this one in good shape and let him have it for what i have in it. i will probably wait until my manual arrives before turning to iboats so i dont get 17 posts about how important a manual is and none about what your problem is.
 
Well I guess I'll update this in case anyone else ever has a similar issue. I managed to get steady and strong spark out of my good coil by taking the bad coil out of the circuit. After I got spark I swapped the other set of coil wires to my good coil to ensure that both were getting power and I had no spark.... Kept cranking and got a few weak and intermittent hits. Popped the flywheel off and.... the insulator block is cracked pretty good and the contact on that side is far from being set right. About to order the coil and see if I can find those insulators somewhere.... Iboats and marine engine say they are NLA parts but hopefully someone makes aftermarket or someone on eBay is willing to take my first born as trade. Will update when I get the parts and test.
 
Well after some searching I found that cdi does make the insulator blocks... Part number cdi-994-3981. Cheapest I could find them with shipping to VA was wholesale marine. Total was 15 and some change for 2 of them.
 
Ahhhh... the phase maker ignition.
Check all the wires under the flywheel, the insulation gets real soft. I had the same problem with a 200 model, cracked insulator blocks, then I read about the insulation, and sure enough, 3 or 4 of the wires from the stator to the coils were exposed. Replaced the wires and the blocks and she runs great now....knock on wood.

Link and Sync is important as well.
 
It lives!!! Got my parts in today, installed and now I have spark on both cylinders. Definitely needs a carb kit but it started and I managed to keep her running for a while! Thanks for the tip work2fish. I went ahead and changed the wires while I had the insulator blocks out, did away with the kill switch by permanently grounding that wire to the block. Still waiting on the impeller and need to find a carb kit then it should be ready for a test run.
 
Glad it worked out. One more thing, don't use the kill switch to shut the motor down, choke it off. Something about the fact how it sends the voltage to ground instead of interrupting the circuit creates problems. I think that is why the insulator blocks are such a problem. I don't know how true it is, but I haven't used the kill switch in 2 years. I just choke it to kill it.

Link N Sync is the synchronization of the carb opening and the timing advance. It's in your manual under timing procedures.


Andy

Just reread, you already bypassed your kill switch.....
 
Thanks again for the advice. I was just able to get back to this motor again.... Been underway for a bit. So when I start it up its idling super fast like I have to put it pretty far down into the shift range to idle normally and the idle adjustment doesn't seem to be doing much for it. Sound like this might be cleared up by the link n sync? Thanks for any advice.
 
been a few days since i messed with it but after taking a good look at it i noticed that the throttle follower arm was already contacting the control cam or whatever its called when the throttle was in the start position by about an inch past where it should be at that point. loosened the screw and set it so it was just contacting that cam at the start position and it fired right up and idled like a dream for about long enough for me to set the idle screw...... then started running rough and vibrating.... pulled it out of the water and popped the plugs out. spark on the top cylinder no spark on the bottom cylinder... the coil i didnt replace popped on me... showing open from where the plug wire attaches to the ground on top of it the good one shows short. i knew i should have not been a cheap skate and ordered both of those coils. oh well lesson learned. new ones on its way so hopefully i'll get it on the water by weekend.
 

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