1991 force 50hp wiggling coil and cd module bracket kills one cylinder

[edauth]

Posted other thread about lost spark on one cylinder and tested stator and trigger and found good so I put new power pack on. Boat ran perfect for about 2 minutes, then same issues. I found out if I push the bracket that holds ignition module in towards engine it works perfectly, and if I pull it out it misfires on one cylinder. I then rigged up a zip tie through the bracket to put pressure towards engine to finish the day. I am figuring it is a grounding issue but why does it do this, there is only 2 bolts that hold it on and they are both tight. Just confused right now.

 

[Barnacle_Bill]

Re: 1991 force 50hp wiggling coil and cd module bracket kills one cylinder

Sounds like the bolts are a little too long and they are bottoming out .

 

[Eddie Rivera]

Re: 1991 force 50hp wiggling coil and cd module bracket kills one cylinder

Same thing happened to me, I've had a few posts about this. In my case 3 different times was a wire from one of the 2 ign. Coils that was bad and touching ground. There is very little space behind the pack and as you push in and tighten up you squeeze the wires too much and also pinch them. What I did was I pulled everything out and checked every wire from tip to tip, some I replaced cuz they were a bit lose at the connector some I added shrink tape others I covered with liquid tape. But at the end if the day it was wires pinched open. I'll include some pictures

 

[MickLovin]

Re: 1991 force 50hp wiggling coil and cd module bracket kills one cylinder

It probably isn't a bolt issue at all more than likely a loose/broken cable from the movement caused from it being loose previously, or as Eddie mentions, a pinched cable or even a loose negative can cause all sorts of intermittent problems, I have seen cables look fine on the outside but when stripped back, they were only joined by what was lucky to be a strand especially after being pinched, not so much on outboards, just in the electrical game period.
If your cdi or coil was loose though that would be a concern.

 

[jerryjerry05]

Re: 1991 force 50hp wiggling coil and cd module bracket kills one cylinder

Sometimes the wires from the stator/ trigger.
The wires on the trigger are very thin and under the shrink wrap the connector breaks.
The same with the stator.
If I suspect there is a "short" I replace all the spade connectors.
The stbd. motor would start but miss. Then it would pick up and run right.
It sat for about 3 mo. Started it up and the miss wouldn't go away.
I started checking the trigger wires and the first one I touched came loose.

 

[edauth]

Re: 1991 force 50hp wiggling coil and cd module bracket kills one cylinder

Checked all wires and rerouted and still same issue. Keep in mind power pack is new so the wires are in good shape, and all trigger wires I put new terminals on . When I was messing around, I took both bracket bolts out and it was just sitting there and it ran perfect with no change when wiggling wires or bracket, but when I bolt it back up the condition comes back, and even if I take one of the two bolts out it runs perfect. This is still very confusing to me. So I went back to the zip tie holding pressure on the top of bracket in towards powerhead with bolts installed and runs fine. I know this isnt necissarily right but it makes it work til I figure out what the issue is. Thanks and keep any more ideas coming.

 

[pnwboat]

Re: 1991 force 50hp wiggling coil and cd module bracket kills one cylinder

Sounds like there is a wire that is getting pinched between the bracket and the block. I know what you're going through. I've looked at some motors behind the coil/CD Module mounting bracket and it looked like a big ball of spaghetti! Just takes some time and patience.

 

[MickLovin]

Re: 1991 force 50hp wiggling coil and cd module bracket kills one cylinder

Possibly a broken cable inside it's insulation and when you bend it to put the cdi on you are pulling what fragile copper cable apart inside the insulation, I have seen cables lossing continuity, just by bedning the due to being in the one place with heat, the copper inside becomes brittle, you move some wiring while you do adjustments to the motor, then the cable has high ohm continuity due to internal breakage. Mostly this is caused by either a pinched cable put under heat stress or just lessening it's insulation resistance and even more so when bent. Conclusion, check you wires from the cdi make sure you feel no breaks in the cable or you may indentify a pinched cable, if you have enough cable from the cdi when you indentify the break or pinch, you may be able to cut the cable and re-join with insulted connectors, which you could tape and smear silicone over the tape. Sorry if I rattled on a bit.

 

[edauth]

Re: 1991 force 50hp wiggling coil and cd module bracket kills one cylinder

Finally found culprit, took it back out one more time and on the new power pack one coil lead is directly lined up with a bolt behind where it mounts to powerhead and wore through insulation and was grounding out on the bolt. Only bad thing is it hits right where it comes out of pack so not possible to reroute it, I just put a washer behind the bracket to push it out a bit, and put some liquid tape on back of power pack. Thanks for all the help guys. And a bonus, I didnt have to pay the shop 300 bucks to fix it

Eddie, sorry I didnt pay more attention to your pic because that is the EXACT same problem I found, I was just being ignorant and thought the power pack is NEW why would there be a bad wire LOL. But again thanks to everyone.

 

[Eddie Rivera]

Re: 1991 force 50hp wiggling coil and cd module bracket kills one cylinder

Hey man, I'm in the same boat here. I have been dealing with my motor since I bought it a year and a half ago and have never had it running at least 1 day in the water. I too refused to pay a boat shop after they wanted me to pay for 8 hours of labor on a job that took me 3 hours with no experience and only relying in the iboats forum angels you see here, shop wanted $1,290 to change out my exhaust gaskets and $630 to rebuild my carburetor and replace fuel lines. He'll no!
So I'm still identifying the best ways to install the wires behind the ignition pack and I covered the bracket's holding bolts with a small peace of wire hose and first used some liquid tape on the head of the bolt. Those wires I found out need their space and proper routing as to not touch rub or be pinched by bundling them or not using the right spacers in my case the spacers were missing and the coil packs being attached behind the bracket or in front. Good job and thanks for sharing with us all and passing on your knowledge. And thanks to the iboats angels!!!