I called CDI and they said just wire it with a NC microswitch on the ground for the ignition amp so that when I shift it breaks the ground and stumbles. I'm not sure if it's going to work though. A marine mechanic friend of mine said that the dog gears in an OMC don't like to "unlock" if the ignition just gets cut like the Merc's do. I'm going to give it a shot and see what happens. If need be I'll wire in the ESA.
OMC didn't use a simple ignition "interrupt" like the Dog-Clutch Alphas use. I don't know if the dog-undercut angle is the same for a Mercruiser or not.
OMC originally used a 3° "under-cut" angle and later changed to a 5° "dog" because they thought 3° wasn't enough. (The problem turned out to be lower shift cable defects)
If Mercruiser uses 3° it's possible that a simple momentary interrupt will reduce torque on the dogs enough to get them apart. If you have 5° dogs, maybe not.
You will know because it will take a fair amount of force to pull them apart and if it's a "Push" on the (Lower Shift) cable vs "pull", they may not come apart at all!..........And this means that it will come out of the "pull" gear, but NOT come out of gear when you're pushing on the (lower shift) cable etc.
The ESA actually "pulses" the ignition making the engine "lope" and it's during the momentary "torque-low" that the dogs can be easily pulled apart.
If you have regular electronic ignition you should be able to wire in a CDI ESA unit and they will be able to tell you how it should be connected. You want it set up so that it actuates only when coming out of gear.
If it actuates going
into gear, linkage, shift actuator, lower shift cable "drag" is causing the thing to actuate (The tension of the shift interrupter spring is what allows the shift interrupter to move far enough to operate the ESA.
When going into gear, the shift interrupter will usually move, but shouldn't move far enough to operate the switches..... If it does, it's usually due to lower shift cable binding (corrosion, bent, damaged cable etc) or the internal shift mechanism in the drive.
Set up properly, a Dog clutch clutch Cobra will shift into gear very nicely, and come right out of gear with only a momentary actuation of the ESA.
And for those of you who say I can't do that for whatever reason I don't need to hear it. I changed the starter to a marine one and things like the head gasket and freeze plug are no different (I checked).
The reason the ABYC (and USCG) says the pump should be within 12" of the engine is that the fuel line from the pump to the carb/EFI unit is usually steel and the pump is mounted on the engine.
The fuel line from the tank to the filter and pump is flexible USCG A1 fuel line because there's an anti-siphon check valve at the tank.
You cannot have a "hard" line from the tank to the engine because the engine moves slightly on the mounts ....possibly enough to cause the line to crack or break.
The (flexible) USCG A1 fuel line from the tank to the engine is under suction (pump at engine) .
So even if a fitting leaks, becomes loose or the line "breaks", the pump will clear the line and eventually "kill" the engine........ and because of the anti-siphon check valve, fuel can't siphon out of the tank into the engine compartment.
(if you have a tank transfer pump it cannot happen either because there's no pressure from any tank TO the engine)
If you have a pump in the tank (and even Mercruiser doesn't do this) you can have a situation where, if the flexible fuel line from the tank to the engine breaks/cracks/leaks, the pump WILL pump fuel into the enclosed bilge below the engine. (BOOM)
This might be what Maclin was trying to illustrate above. Just about all the EFI engines in boats have the (electric) pumps on the engine and have hard (stainless, etc) fuel lines from the pump to the EFI/carb, and if the engine quits, the pump loses power (as yours probably does also)
No one wants to "beat you up" on your project. But you could place yourself at great liability if you have a "boom/fire" and the neighbor kid is sitting in the back and gets hurt or killed. And believe me, the "kids" family "Slip-& Fall" lawyer will have pictures and documentation of everything "illegal" and all the social media info (here and any other place you have documented your project) to prove intentional noncompliance with all those USCG/ABYC guidelines. (they can then call it "Negligence") And if you were to sell that boat to someone else and they killed themselves, you can bet the family would come back looking for whomever set the boat up to "blow"............It isn't all about just starter, alternator, and core plugs......
All most of us want to do is ensure you have all the info on what you're doing and have "Eyes wide open"....then we'll just watch from afar!
Regards,
Rick
