1989-91 Force 85 Stator/CDI Box problems

[poison26]

Hi all. I have a Force 85 thats between the years of 1989 and 1991 (haven't looked up SN# yet). I took it out after not running it for 2 years and discovered the 3rd cylinder was not getting a spark. Each sparkplug has its own ignition coil. Its a 3 cylinder engine and the top 2 cylinders are controlled by 1 CDI box and the bottom one is controlled by a 2nd CDI box with the extra wire not connected to anything. <br /><br />The second CDI box that controls the bottom cylinder is not working. New sparkplugs are in. The ignition coil for the 3rd cyliner is working fine as I tested it by hooking it up to CDI box 1. CDI box 2 does not produce a spark for either the unused output (for cylinder 4 if it had one) or the regular third cylinder. The engine was working fine the last time I fired it up 2 years ago, so it was a sudden problem not gradual.<br /><br />This leads me to the conclusion that either the CDI box 2 is bad or the stator is bad. Both of which are expensive, I believe. <br /><br />My question to you all is: Is there any easy way to test to see which one of these items is the problem? I noticed there is a terminal block with the exact same wire setup for each CDI box. I was thinking of switching these wires to see if its the CDI box or not but that seems risky. I have purchased the Force 85 repair manual but haven't looked to closely at it yet. <br /><br />The Fuel system is working fine besides this. I ran 4 tanks of gas through it on these 2 cylinders only getting about 30% its normal power because of this problem (No carb issues). <br /><br />I can use a multimeter to test the connections on the terminal block but am not sure what kind of signal to look for (resistance, VDC, or VAC) from the stator blue/yellow wires. I also don't know when to measure these leads (engine off, on, while starting?) <br /><br />This is my first time working on a boat engine but I have extensive knowledge in computers and electronics. <br /><br />What I'm looking for is anyone out there that will say to me: "I had the same problem and it is _______ " Or "Sounds like your heading in the right track but whatever you do don't do _______". Any info any of you boat engine guys can give would be great. <br /><br />Thanks a ton,<br />Erik Von Schuessler<br />fireflyz@hotmail.com

 

[Schoe]

Re: 1989-91 Force 85 Stator/CDI Box problems

You are correct about unit #2. Get from E-Bay as they are far cheaper than the marine stores. I have seen them for between 10 and 50 bucks. Stators are available as well but the stator sensor for plug #3 can be tested by taking cdi box 1 and puting it in place of cdi box 2 and checking for spark if no spark then it is the stator if spark then cdi box 2 is bad. Check the wiring as well.

 

[poison26]

Re: 1989-91 Force 85 Stator/CDI Box problems

I tested the Voltage on the stator while starting it and both boxes were recieving around 175-200V AC which is what the repair manual I bought says it should be. I also checked the resistance of the stator coils and it was around 750 ohms and the trigger wires were around 50 ohms which is also what the repair manual says they should be. So I went to boatfix.com and got a new CDM module for $178. Wired it up and PROBLEM SOLVED. All 3 cylinders are sparking now. Every mechanic shop told me a replacement CDM module was $300-500 so don't get pulled into that BS. THe one I got was brand new CDI electronics and looked better than the stock one. So the moral is: Take the time to buy a repair manual and see if you can fix it yourself as I did through a process of elimination. It could save you hundreds or even thousands.