1988 Force Spark Issue

Wide_N

Petty Officer 2nd Class
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Jul 14, 2015
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I picked up a 1988 Force 50 HP. I also picked up a parts motor from the same guy. The guy said that he had switched out the coils on the motor. The motor I am working on has the blue coils and power pack. The other set does not have a separate power pack. It looks like there are two coils/power packs that are each separate units. I am only getting fire on one cylinder. Here is what I have done so far:
1. Tested the stator voltage (With DVA) and it is good. Yellow to Blue
2. Tested the Trigger Voltage and it is good after repairing the wire ends.
3. When I switch the coils the spark switches with them so I am assuming my coils are good.
4. All resistance is good.

I believe it to be the switch box but just want someone smarter than me to give an opinion. I guess the thing that I question a little is the stator on the parts motor has two blue and two yellow wires. I would assume that this stator would match up with the coils from the parts motor so that each power pack would be fed. Any help is appreciated. I am sure I have forgotten something that will be needed for someone to help me.
 

Jiggz

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Oct 23, 2009
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I am presuming you are working on the motor with a prestolite ignition system ( CD module) and the parts motor has the thunderbolt ignition system (switchbox).If you switched the coils, i.e., top coils goes to the bottom while the bottom coil goes to the top and the spark follows, it means one of the coils is bad.

Here's the logic to that one. Let's say before the switch the top coil got spark. After the switch if the bottom coil was good then there should still be spark at the top. But you said the spark follows, which with my understanding, after the switch the spark went from the top to the bottom, hence following the top coil. Meaning initially the bottom coil is bad.

For a quick remedy get one of the coils from the parts motor and try again.
 

Wide_N

Petty Officer 2nd Class
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Jul 14, 2015
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Actually the coils are not the same. After researching I found this out. The stator on the "good" motor only has two wires. The stator that is supposed to go with the blue setup actually has four. Two blue attach together and two yellow attach together. Could this be my problem of getting fire on only one cylinder? I know it is not correct at the very least. My plan today is to try and hook up the coils that actually go with the stator and see if it does anything.

I don't think I explained myself on the switching the coils very well. I switched the wires that connect to the coils. Before I switched them the bottom coil had spark and the top did not. After I switched them the top coil had spark and the bottom did not. So both coils had spark at one point.

Thanks for the help!
 

Jiggz

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No Title

There are two ignition types with the 1988 50 HP. One with the CDI system that uses the combo coil and cd module units. There are two of these CD modules/coil units. The stator for this ignition system has two blue wires which are used to feed each of the CD/coil modules, i.e. one blue wire to #1 CDI unit and the other blue wire to the #2 CDI unit. Each CDI unit has a black wire that connects to ground. There are also two yellow wires from the stator which connects to the rectifier for charging the battery.

And then there is the "D" type which uses the prestolite ignition system which has two separate coils and one CD module that feeds both ignition coils. The stator for this unit has 6 wires, 2 blue (or brn/blu) wires, 2 yellow (or brn/yel) wires, and 2 green/yellow (or yellow) wires. For connecting the CD module to the stator, the two blue wires (or brn/blu) go together to connect to the same color on the CD module and the same with the two yellow (or brn/yel) wires. The other green/yelllow or yellow wires go to the rectifier unit. Here's a wiring diagram of the two types of 88-50HP Force. Verify which one is yours. You might want to save it and then view it enlarged to make it readable.
 

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Wide_N

Petty Officer 2nd Class
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I believe that was part of the problem. The guy who had it last tried to use the D coils on a non-D motor. like you said, it is supposed to have two wires that go together from the stator (X2). I rewired everything with the non-D coils and have decided I have a faulty coil/pack. Hopefully I can find a used one.
 

Wide_N

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Jul 14, 2015
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I got it. The stator was not correct. Got it all on the correct motors and good to go!
 

jerryjerry05

Supreme Mariner
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May 7, 2008
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17,923
Great it's working!!
​Be careful when changing gear oil.
Don't remove the wrong screw.
 

Jiggz

Captain
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Oct 23, 2009
Messages
3,817
It is the gear shift pivot point. And it's a SOB to reinstall if you inadvertently remove it.
 

Wide_N

Petty Officer 2nd Class
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Jul 14, 2015
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😂I did it with it laying down putting a new impeller in. Guess I got lucky!
 
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