1989 Force 150 ignition

[iCam]

OK Force gurus, I need some verification on my troubleshooting before I buy parts.

History;
I got the boat from my neighbor last year. The 1989 Force 150 (1508E9A) had a couple of issues that I corrected. One of them was a bad CD unit. There was no spark on 1 cyl. and of the units I had, the spare side on the unit controlling the #3 cyl, was also bad. I bought a good used unit off an auction site and installed it. Engine ran fine. I ran out of boating season last year before I could dial in the timing, so I winterized it. I disconnected the fuel line and let the engine run on muffs until all fuel was out of the lines. Drained the LU of water, removed the batteries, covered the boat and parked it on the side of my house.
Note the Engine ran fine.

Now I am getting it ready for the lake thinking all I have to do is start on the timing, dial it in and I am floating.
Well I could not get the engine to start, or even to catch. So I checked my spark, and I do not have spark on #3 and #4 cyl. I checked my connections and found 1 that was questionable (even it was the trigger to the CD unit for the #5 cyl) I repaired it re-tested to no change. Thinking I have a bad CD unit I started to test them by moving the known good unit (#1 and #2 cyl.) to the other locations. Still no spark on the #3 cyl, but got spark on the #4 cyl. At that point I switched the #3 cyl ignition coil with the #2cyl one, and got spark on #3, but not #2.

This tells me that my stator and trigger are good (correct me if I am wrong), and I have 1 bad ignition coil, and a bad CD unit.

What raises red flags for me is I am questioning how 2 good electronic units can work until I let them sit with no voltage and they go bad. So I am wondering if there is another part (ie. breaker, relay, resistor, regulator) to the ignition/electrical system that could go bad and cause these units to crap out. I don't want to buy a good unit and put into a system that will break them.

Am I over thinking it? or is there something I am missing?

 

[pnwboat]

Re: 1989 Force 150 ignition

I feel your pain! The Prestolite ignition system with the blue coils and CD units can be a real pain to troubleshoot. It does sound like you definitely have a bad coil. The problem moves around with the coil. As far as the CD units, I wouldn't buy a replacement just yet. Check the spade lug connectors that go from the CD units to the terminal block. Sometimes there is a small piece of black heat shrink right where the wire is crimped/soldered to the spade lug connector. I've found a few intermittent problems due to a broken wire inside the heat shrink. You can't tell that there is a broken wire because the heat shrink holds the wire to the spade lug connector. In one instance there was one strand of wire left on one of the trigger lines. It OHM'ed out OK but apparently it was not enough to pass the actual trigger signal. Re-soldered the connection and it fixed the problem. Also make sure all the coils are properly grounded to the coil mounting plate. Make sure the coil mounting plate has a good ground connection to the block. I believe that there is one wire that goes from the coil mounting plate to the block.

NOTE: Also be aware that a bad CD unit may fire the coils, but can cause a good one not to fire the coil(s).

 

[iCam]

Re: 1989 Force 150 ignition

I agree with you on those stupid spade connectors. I think I may just inspect them all, re-solder and heat shrink any questionable and re-test. I think while I am at it I will do the same for all the spade connectors on the engine. I figure a 23 year old engine might have some bad ones. might as well fix them while I am on a roll.

Also I am trying to research an alternative to those CD packs. On this post (http://forums.iboats.com/showthread.php?t=484275) Jeep8589 used a MSD unit. Now this would only work on 1 cyl. Are there any known (single unit) systems that would work on a distributor-less 5 cyl marine engine? I am going to start to research the ignition systems of circa 1980-90 outboard ignitions and see if other manuf. have something that will work and is a little more reliable/ available. I have a buddy that is a GM ASE mechanic, and he seems to think that Buick had put out a similar ignition system. Problem with that is the ECM, crank and camshaft sensors the autos require. He is going to look into it and try to see if there is a way around those roadblocks.

 

[pnwboat]

Re: 1989 Force 150 ignition

I have a 1988 125HP motor. I looked into the MSD systems. The MSD units for the distributorless ignition systems were more than what I was willing to spend. The lower cost units either required a distributor, or you would have to have a separate box for each cylinder, also expensive. What I ended up doing was converting my Prestolite system to a later model Mercury Thunderbolt system that uses the CDM modules. The CDM modules are combination coils and CD unit built into one. I scavenged used parts over period of about a year on line. Had to get a different flywheel, stator, trigger. I also upgraded the rectifier to a regulator/rectifier. Had to make some brackets to mount the coil plate. Works great! Best thing that I've done to the motor....so far. It's been two years now and zero ignition problems. The spark plug wires are replaceable on the CDM modules. They are not replaceable on the old Prestolite blue coils.

Here's a picture before.



Here's a picture after.

 

[iCam]

Re: 1989 Force 150 ignition

Hmmm, sounds familliar. Did you have a thread on that conversion? Did you use the late model Merc flywheel/stator along with the CDM modules? Did you run across any issues with mounting the stator and flywheel to the force block/crank or did you have to do some modifications?

That sounds like what I want to do. Any P/n or info you have I would love it, and I will start piecing together a shopping list and start collecting myself.

 

[pnwboat]

Re: 1989 Force 150 ignition

I don't think I did a step by step thread on the conversion, just a few comments and pictures. Yes, I used parts from 1996-1998 for the electrical stuff (stator, stator mount, trigger, CDM's w/mounting plate and regulator). The flywheel is from 1992-1995 motors. They changed the diameter of the crankshaft snout starting around 1995-1996. The hole in the flywheel is bigger from 1996-1998. You can tell by the flywheel. The 1996 and later flywheels have a lip that sticks up about 1/2 - 3/4 inch around the center hole, and it's threaded internally. The 1992-1995 flywheels have the six separate magnets like the 1996 and later, but have the same size crankshaft snout as the 1991 and earlier motors. These flywheels have a slight ridge, maybe 1/16 - 1/8 inch high, about an inch wide around the center hole.

I just realized that since your motor is a 5 cylinder, that may present a problem. They made a change in the design of the triggers when they went to the CDM ignitions. The Prestolte triggers (like yours) and some of the early Thunderbolt triggers on the non-CDM ignition systems used a wire coil. You can measure these with an ohm meter, 48-52 ohms. The triggers for the CDM ignition systems use a solid state Hall-Effect sensor. I don't know of any Hall-Effect type triggers for the Force 5 cylinder motors. I think they stopped making the 5 cylinder motors around 1994. The signal output for the coil type trigger is .5 volts. The signal output for the Hall-Effect trigger is 1.5 volts, or three times higher.

Here's the problem....I don't know if the CDM system actually requires the Hall-Effect trigger (1.5 volts) to fire the CDM modules. If it does, then you cannot upgrade. If it doesn't, then it might work. Since as far as I know, they never made the Hall-Effect triggers for a 5 cylinder motors, you're in uncharted waters so to speak. Since mine was a 4 cylinder, I was able to use off the shelf parts.

Having said all that, my Prestolite ignition system problem that I was having was most likely due to a bad stator. I was swapping out CD modules and coils until I was blue in the face. I upgraded so I never really had a chance to really test that theory out. The resistance readings on one of the windings was lower than the other. I don't remember the exact readings, however, the one that read lower was just borderline from reading the minimum resistance according to the charts. Both stator windings should read very close to being the same.

 

[iCam]

Re: 1989 Force 150 ignition

Alright here is what I did. I went through and cut off all those spade terminals all together (I found 2 questionable connections) and re-terminated to a new terminal block. I removed those old ones and put this other style on. I like these because they are smaller and have 2 sides to them. I also verified all my grounds, measured the trigger and stator leads, and those all seemed to be fine (I forgot to measure the trigger voltage, I will do that and get back to you. Here is a pic;



While I was in that deep I measured all my readings on my coils and CD units. I noticed that #2 Cd unit- 2nd cyl (#3 cyl.) were bad readings. I knew this though. the only other reading was on the #4/5 unit 1st cyl. (#4 cyl). Only one bad reading. Here are the readings of the CD units;


When I did the reading on the ignition coils they read all good. I am not sure why the #3 cyl is giving me an issue. I will probably get one anyway, and if it is not the issue, I will have a spare (which is not a bad thing).

 

[bentle]

Re: 1989 Force 150 ignition

Just a thought. The wires that come right out of the trigger housing can break and if broken or shorting out far enough up in then impossible to repair.
This happened on my 89 125 force original trigger and I ended up replacing it.
The new one was upgraded and had less wires to contend with and made it easier to reconnect.

 

[iCam]

Re: 1989 Force 150 ignition

Thats what I had thought originally (or the stator and flywheel). But when I switched around the CD units and ignition coils to different locations, using the same triggers, I was able to get a strong spark at the plugs that were not firing before. In fact when I switched them around the problem followed the units in question. I can't remember if I checked the resistance of the trigger coils, or if I had checked the voltage, so I will do both again today.

I may of found a solution to the CD units though. I am going to try and contact the manufacturer with some questions though and verify how they exactly work but I found some high performance after market CD units for 2 stroke ATV's. Each unit controls 1 cylinder and they are around $25 each. If they do as I suspect, they will take the trigger and fire to the ignition coils with little modification. There are alot of "if's" on this, but I will dig into it a bit more.

 

[pnwboat]

Re: 1989 Force 150 ignition

If you have any electronics expertise, here is an article on how you can build your own replacement CDI module. I never actually tried this as I was able to use off the shelf stuff. Just another possibility if you feel adventurous. It does explain in general how the CDI module works.

http://www.siliconchip.com.au/cms/A_110499/article.html

 

[iCam]

Re: 1989 Force 150 ignition

You read my mind, I was just about to dig into one. Thanks for the link, I will let you know how it turns out.