Wont rev past 4k -ESA issue?

[SteveRI]

88 Fourwins 205 sundowner 4.3 omc cobra 4bbl won't rev past 4k unless I unplug the esa - then it runs strong, just won't shift...

2020 when I had the motor out for transom replacement, I fitted a new cdi esa
123-9898-P since my original hadn't worked for awhile.

2022 I finally finished my project and tried to do some boating but couldn't go over 3500 rpm in the water. Tried tune up, new fuel since the boat sat 2 years, eventually put it on the back burner.

2023 installed new carb - no change. That is when I realized I could duplicate the concern on the trailer. I also found that if I disconnected the 2 pin connector for esa the boat ran great. Unplugging just the switches doesn't help. Contacted CDI (now they charge $35 for 30 mins of advice), they said sounds like a bad esa module, too old to warranty, good luck. They also recommended switching to a cdi 123-9800. I ordered one and installed - no change. Then I swapped in my original ign coil I had replaced years before and it seemed somewhat better. I figured maybe the replacement coil had some resistance issue (cdi says they need 3 ohms) and I gently used the boat a few times - stalled a few times idling in gear, didn't like to go fast...

2024 - I really want to be able to buy replacement coils without fear they will not work. I bought and installed pertronix unit to replace points, installed their recommended flame thrower coil 3 ohms and ran a new wire from alternator to bypass the 1.5 ohm resistor wire. Set timing to 6°. The damn boat still won't rev past 4k unless I unplug the esa. What am I missing!?? 13.5v at coil at idle, ballast wire I originally overlaid has now been cut, alternator output on orange wire is .8v higher than output at bottom post that feeds coil/esa only when pertronix is connected - maybe internal alternator issue but I think 13.5v at coil should be enough.

Sorry for the very long story/ explanation but I'm at the end of my rope here. After doing a transom and stringers I really wanted to enjoy this boat for awhile...

Steve

 

[SteveRI]

Maybe alternator issue? It does surge past 15v @ 800-1300 rpms. Thought about wiring alternator pos to sense as I've seen mentioned in multiple posts but I have a question about that too, the coil and esa feed off the sense side. Would I move those to the excite side, then run pos to sense?

Overstroke switch taken out of the picture with the switches disconnected?

 

[bruceb58]

Is the ESA spring being depressed? Does your ESA have two switches?

Show a picture of the ESA switch plate both in gear and in neutral.

 

[SteveRI]

I'm not home so can't take a Pic at the moment.

I have 2 switches and neither are being pressed (boat is in neutral). I have disconnected the connector for the 2 switches to take them out of the equation but it didn't help.

When I press the main switch at idle it does cause the motor to stumble. When I hold the overstroke it does lockout the main switch. In forward gear it does lockout the main switch.

I also disconnected the lower shift cable, put the shifter in forward position so it was pressing the overstroke switch and it still had the issue.

 

[Lou C]

I had a similar issue with mine about 10 years ago. What I found was that the little buttons on those switches can wear and stick on. At the same time the ESA seemed to go bad not stumbling the engine. I replaced the switches and the ESA using CDIs 123-9898-P as you had and it’s worked fine ever since. Also re-wired the sense wire as per instructions I got from ARCO marine when I bought a new alternator from them. That eliminates the over voltage condition of the stock wiring. Went from 15.5V at the batteries to 14.2V.

 

[bruceb58]

Another thing that might be worthwhile doing is disconnect the tach. A failing tach can mess up ignition. Disconnecting the feed coming from the coil to it and running is a simple test.

 

[Lou C]

True I heard that was an issue with some Faria tachs

 

[SteveRI]

Another thing that might be worthwhile doing is disconnect the tach. A failing tach can mess up ignition. Disconnecting the feed coming from the coil to it and running is a simple test.

I did disconnect the tach ground at the tach with no change. It was easier than disconnecting at the coil since the tach ground and esa ground are crimped into the same eyelid terminal. I could cut them and crimp separate terminals on each wire to test if you think disconnecting at tach isn't a good enough test.

 

[SteveRI]

My most recent thought is power from alternator. I rewired power wire from alternator to sense post, R/PU wire from ign switch (mines actually P/W for some reason) taped up, purple wire that feeds esa and my new wire bypassing resistor wire feeding coil connected at excite post. Now my charging voltage seems steady and happy. Battery voltage post shows 14.2v - great!. Excite post (feeding esa, coil, and now pertronix) is only 13.2v (is this normal?). Maybe these 3 items are too much of a load to share this circuit? Unplugging esa frees up some power for ignition? I could overlay a power wire straight from the battery to coil and retest. Pertronix troubleshooting does say -

MY VEHICLE IS MISFIRING OR BREAKING DOWN UNDER LOAD. WHAT SHOULD I DO?​

This problem is NEARLY ALWAYS associated with low voltage at the unit, preventing the unit from operating correctly. The unit is actually turning off, and back on as the coil charges and releases energy.

 

[Redrig]

Excite post (feeding esa, coil, and now pertronix) is only 13.2v (is this normal?). Maybe these 3 items are too much of a load to share this circuit? Unplugging esa frees up some power for ignition?

I would think that 13.2 should be plenty , I would try running that circuit straight from the battery as a test like you said. To see if that changes the problem.

If it does solve it , you can run them all off battery through a switched relay for a permanent fix.

Just a thought

 

[SteveRI]

I would think that 13.2 should be plenty , I would try running that circuit straight from the battery as a test like you said. To see if that changes the problem.

If it does solve it , you can run them all off battery through a switched relay for a permanent fix.

Just a thought

That will definitely be my next step if the direct power line helps.

My last idea (and I may regret it one day) is to put the esa on a switch using a relay. The esa works, so I imagine it will shift well in the water. Unplug the esa and the boat runs good through the rpm range. If I put the esa on a switch I can have it on while docking and shut it off while cruising. Seems hack but I'm out of ideas.

 

[SteveRI]

Just want to give you guys an idea of why I want to enjoy this boat so much! I've spent enough hours on the boat in the driveway and just want it cruising again! I appreciate all and any ideas!

 

[Lou C]

great job on the transom, motor mounts, and deck!
I think my boat (200 Horizon) is the bowrider version of your boat....
I wish I could be more helpful, my old boat still has the points distributor, the only things that have been changed from OEM OMC is the ESA module, and the switches, they acted up about 9 years ago, causing low rpm issues, because the switches stuck on and then the module failed. Replaced both and no problems since.
My boat did have a similar problem when I first bought it 22 years ago, it would start, and rev in neutral, but would not plane out the boat. I checked everything I could think of then took it to a very good mechanic, he found that the anti siphon valve was corroded and restricting fuel flow. Replaced that and no further problems. Boat still runs strong given it is a little 4.3 in a fairly heavy boat.

are you SURE that the interrupt switch isn't sticking?

 

[Redrig]

Don't consider the relay concept a hack job . If done right those newer Bosch relays are great. It takes the load off of the ignition switch . I think it's an upgrade .

I was researching installing a DUI distributor into my boat . It's considered a "best practice" to feed that dizzy right off the battery with a beefy wire via a relay.

Maybe you just have an old wire with high resistance somewhere in that circuit that is limiting performance

And well done on the rebuild. That looks fantastic