Engine Loosing Power. Bayliner Capri w/85hp Force Outboard 1988

[Themanofsteel]

I have a Bayliner Capri w/85hp Force Outboard 1988. For some time now my engine has intermittently lost power. • Sometimes it worked fine. I made it all the way to Catalina and Back with no problem at 35mph. • Other times it would loose power and I couldn't get it past 15mph. Sometimes I'd have it at full power then it would start to sputter. • Then again I'd take it out and no problem all day with maybe a hiccup here and there. I checked the carbs, the inlet and float. Made sure they were working and adjusted. I looked at the Reeds and their are no chips or cracks. I did a WOT test and saw not fuel kicking back. I have NOT done a compression or timing check. I checked the spark with a spark tester. The top cylinder is getting weak spark. The 2 other cylinders seem to be getting a good spark. I checked all the wires on the terminal board and they are not broken and are making good contact. Also, I have a inline fuel filer and it stays full. I’ve attached a photo of the side of the engine with the spark wires. What is not working here? I replaced the spark plugs in July.

 

[Jiggz]

When you said you have an inline filter, is it located between the fuel pump outlet and the carbs' inlet? If not then it needs to be relocated. You need to ascertain the spark problem on #1 and #2. An inline spark tester will help to determine if there is spark . . . but to ensure you consistently get a spark you are better off using an induction type timing light and bounce of the light on a dark piece of paper to watch the consistency of the sparks.

 

[Themanofsteel]

Filter placed correctly. The first attached picture is before I installed it.
So I tested again with the spark tester. Since it was darker i could see the tester better.
The top cylinder is firing but the spark indicator is really faint compared to the other 2 cylinders which are bright.

 

[Themanofsteel]

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Here are 3 pic of the Sparks. The faint one is the top cylinder.

 

[Jiggz]

Since #1 and #2 are fed from the same CDM but from totally isolated different ckts. The next step is to switch the CDM's. The CDM feeding #3 only uses one of the two ckts so make sure you are aware of this. When switching, make sure you connect #3 cylinder to the same ckt that #1 was originally connected. The reason for this is to isolate the problem. If you connect #3 to the same ckt that #2 was originally connected when you switched CDM's you will never be able to locate the source of the problem.

With #3 connected to the same ckt that #1 used to be connected after switching CDM and the problem follows i.e. meaning the faint spark moves to #3 then you know the problem is that particular ckt on that particular CDM. Next is to move the #3 ckt now to the spare ckt where #2 used to be connected to. And this should resolve your problem.

However, if the problem stayed on #1 (faint spark) after switching CDM's, then problem could be in the trigger ckt.

 

[Themanofsteel]

I'm not sure what ckt is or means.
But I swapped wiring behind the CDM's, 1 & 3. And I assume I had to also swap where the spark plug wires plug into right.
That is what I did and the Faint spark moved to the bottom. I'm a little confused as to your instructions after determining the faint spark moved to 3.

The 2 Square Blue Boxes are the CD Modules and the 3 other blue boxes with the spark plug wires are the Coils right.
I see what you mean by 1 & 2 being fed by CDM1 and CDM2 feeding 3. CDM2 has and extra unused red connector.
So the faint sparking is not a issue with the Coil?

 

[Jiggz]

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Ckt stands for circuit. If you switched the CDM's correctly and you said the faint spark moved from #1 to #3 then the problem is with the CDM1 (originally feeding #1 and #2 plugs). This means all three coils are perfectly working. So now with the CDM switched, connect #3 coil to the #2 ckt on CDM2 (remember this used to be CDM1 before the switch, where #2 used to be connected before the switched). Here's a diagram to help you. In the diagram the CDM's are labeled based on the number of the cylinder it is feeding, i.e. CDM1 is CDM #1 and #2 while CDM2 is labeled CDM #3.

 

[Themanofsteel]

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So I don't think I did it quite like you intended me to now that i'm reading your reply.
What I did was Connect the top coil to CDM2 then plugged it in to the bottom cylinder.
I also connected the bottom coil to CDM1 and plugged into the top cylinder.
I attached a Pic of what I did.

Not being 100% sure on your instructions, I assumed rearranging the connection on CDM1&2 might be equal to mixing up the spark wires and I always heard you should never do the.
Please bare with me. This gets kind of confusing.

 

[Jiggz]

From your diagram it seems you switched the coils rather than the CDM. And technically, only two coils were switched, i.e. #1 and #3. Note #2 plug is still fed by #2 coil which is still being fed by CDM1. Now note #1 plug is now fed by #3 coil but is still fed by CDM1. The same with # 1 plug is now fed by #3 coil but is still fed by CDM2. However, since the problem followed the switching of the coils, then it means the #1 coil is going bad. To validate this, restore the original wiring and then instead of switchting #1 and #3, try switching #1 and with a known working coil #2. If the faint spark moves to #2, definitely have a failing coil on #1. But if the faint spark stays on #1 the problem is not on the coils but upstream of the coils, i.e. CDM's or trigger unit/wires.

If you decide to switch CDM, that requires physically disconnecting all wiring connections on each CDM and physically switching their locations or slots and rewiring them back. This is the only way as the trigger wires are permanently designated for each cylinder. Make sure you label all wires accordingly and take photos for future reference,

 

[Themanofsteel]

Yeah, I don't think I want to try to switch the CDM. From what you described is seems too complicated. Ill try your other suggestion to validate and will update. Thanks.

 

[Themanofsteel]

I could buy a New Coil for $50 but it's is for a 1989 Force Outboard. Mine is a 1988 Force. They look identical. Would it still be ok to use even though it's 1 year newer than my engine?

 

[Jiggz]

You can. But before shelling out $$$ always validate you actually need a new coil. Where you able to validate the #1 coil using #2? The amount of work involve in replacing the coil is not that much different if you validate by switching.

 

[Themanofsteel]

So I switched coil 1 with 2 and started. The faint spark shows on 2 now.

 

[Jiggz]

Now you know for sure you need a new coil. Yes, the 125 and 85 HP 1988~1989 are virtually identical with the exception of the number of cylinders and obviously plugs. The part number should be F685475 for the original 88-85HP which should be the same for the 125 HP. On going price for a new one costs around $100. And for used ones $40~$50. Goodluck.

 

[Themanofsteel]

Thanks for you help. Appreciate it. One more question. I've always had a some start trouble and backfiring. Would this issue contribute to that?

 

[Jiggz]

Does it happens everytime even when the engine is warm? Or only when cold? Are you following the standard three steps for starting cold? Prime, choke and fast idle?

 

[Themanofsteel]

Yes on the 3 steps for cold starting. It happen sometimes when out on the water. Takes several cranks. Just sort of unexpected. Usually it starts fine. Then randomly it's difficult to start and may backfire a couple of times.

 

[Jiggz]

That is most likely a problem with the ignition system. Report back after replacing the faulty coil and see if the problem persists.

 

[fisheymikey]

i have not had to post my "FIXED" post on ALL my termoil with my 125 1988.

but here is something that i could tell you.. Dont waste your time with a million different test do as follows and you will thank me later.

check all resistance on all components.. stator,coils and trigger. if possible also check voltage when cracking and assure they match the specs for each component. if that comes back ok then BUY 2 new CDI modules. these modules contain a bunch of small components inside and they will fail under load and cause so many different problems. i.e. weak spark, interminent, surge of power loss of power etc... i had amazing help here but the truth of the matter is you cannot diagnose any real certainty without having the core component ignition delivery system being brand new.

 

[Themanofsteel]

What does the core component ignition delivery system consist of?
FYI the Starter and Solenoid have been replaced. Battery connections have been sanded and cleaned thoroughly for a solid connection.

Other smaller issue is the Nav Lights and Horn. They intermittently work and don'r work. Thinking maybe their is a short in a wire. Dashboard lights always work no problem.