Logo

1986 Force 85HP - No Spark on top cylinder

kevinj

Advanced Contributor
My friend just bought a Bayliner with a 1986 Force 85HP. The initial runs were great but he took it out this weekend and lost power. I helped him troubleshoot on the water and we found the top cylinder (#1) was dead. The motor has 140PSI on all 3 cylinders and starts at the first turn of the key. When it did run it had good strong, smooth acceleration so I'm certain the motor is in overall good condition.

Last night we used a spark gap tester and found nothing on #1 but good strong spark (7/16" gap) on cylinders #2 & #3. We took the plugs out and grounded them and there wasn't any spark on #1 at all. I switched leads on the CDI between cylinder #1 & #2. With spark plugs removed I grounded the gap tester to the block to avoid firing out of order. The no spark condition traveled to #2 and #1 now had spark. I hadn't yet found the testing procedures on Outboard Ignition . com but will do more detailed testing now that I have that info.

Here's the weird thing: after putting the CDI leads back on the correct coils, cylinder #1 suddenly had spark :confused: It would only jump about 1/4" gap, but at least it had some fire to it. After reading more info on OBI . com and other sources it seems the wiring connectors on Force motors are very poor. I think a fractured wire in the connector might explain why I now had spark. I probably just jiggled things enough for it to make connection.

Would it make sense just to replace all of the original CDI-to-Coil connectors with marine grade insulated bullet or spade connectors? Surely that wouldn't be a problem if they are all snug fit and di-electric grease is used to keep out moisture.

Thanks and I appreciate any additional info.

KJ
 
Do the tests from OI and changing the connectors might help.
The trigger leads can break under the shrink wrap and stop that cyl. from firing.

Your motor was made with 3 different ignition systems.
Early a models used a plug and play connectors.
Later b@c used the screw down connectors.
Try pulling the wires and see if any break ?
 
Where are you referring to the trigger leads breaking? The wires coming from the coils or out of the power pack? Or are the breaks happening elsewhere leading to the power pack?

The fact that coil #1 had excellent spark after swapping leads from the power pack makes me think it's in the Ppack wiring. If it is a stator issue, wouldn't both cylinders fed by that power pack have poor/no spark?

We'll go with whatever solves the issue, but hoping it's not the power pack. The cheapest I've seen new power packs is $260. That's a little steep.

Below is the style of connector on the Power pack. Is that the 'Plug & Play' type?
Ppack_Connector.JPG
 
Yes that's a P@P
Try e-bay.301940955415 This might work? Make an offer??
The no spark could be the stator or maybe the pack??
Do the tests you can(ohms) with an analog meter.
You could possibly have an aftermarket stator so make sure you know what you have.
Might have to remove the flywheel?

Maybe try swapping the packs and see if it follows the pack.
 
Back
Top