Replacing stator on mercury outboard

[Spycatcher2018]

Dear All
I am thinking about designing a system to replace the electrical output to the switch packs that comes from the coil.
This could be a get you back item or permanent installed either on the motor or external .
Has anyone thought of trying a solid state a DC to AC converter that produces a AC regulated voltage output to the switch pack. This output can be controlled by a rpm switch that switches the voltage to a higher level as the rpm increases above 3000 .It seems very hard to find the total specifications for the coils or any information on the waveform form it produces ,my understanding as an Aircraft avionic engineer it should be something like a sine wave but ,on other sites i have heard it is a three phase voltage, which i am not sure is true as three phase would require either 4 wires or three depending on the star delta configuration, to start designing I would need the max amperage Amperage /Voltage that the coil is designed to produce is this date available or an internal wiring of the switch box so can work out the sccr's maximum rating .
Is this feasible or have people tried and failed .

Thank you all for your time and appreciation
Best Regards
Peter

 

[GA_Boater]

I think you're off on the wrong foot from the get go.

Coils don't feed the switchbox, the switchbox feed the coils, so your basic premise is wrong. And what DC are you going to convert to AC? The stator produces AC, not DC. What do you mean by "replacing the stator"?

And what you want to do is already done by the Merc system and does it well. Why reinvent the wheel?

 

[jimmbo]

Engineers love to change things, even when it works fine, even when they don't understand it, hence the saying 'Better is the enemy of Good'.
Management is the same. They make a change, so they can say they did something, so they can rationalize a Bonus, then when the change fails they return to the old design, claim they solved the problem, and deserve another Bonus. Meanwhile the people who actually work, and the customers, are left shaking their heads

 

[GA_Boater]

Before a system can be redesigned, the workings of original system has to be understood in order to replicate it. This understanding seems to be lacking here.

 

[jimmbo]

Reverse engineering is not the easiest concept, and has shown to create products that are close(close, works with Horseshoes, Grenades, and Nuclear Weapons) to the original, but not 100%

 

[Chris1956]

Spy, Stators are pretty robust, being made of coils and permanent magnets and wiring. Not sure you would ever need your back up system.

Towing insurance covers all kinds of breakdowns, steering, ign, fuel, physical damage etc. I would stick with that approach, vs a back up system for a reliable OEM system.

 

[Spycatcher2018]

Thank you for your Input

The DC to Ac converter is to convert the 12 to 14 volts from the main battery or stator charging coils to an AC signal thus simulating the stator itself . The speed switch in my circuit acts to increase the voltage output once a certain rpm is obtained thus substituting for the high speed coil.


As for the normal operation of the system this is how it works as i understand please correct me if I am wrong .Initially on start up the low speed stator coils provide a lower voltage output to the Switch boxes ,as the engine speed increases the high speed part of the stator provides a voltage increase to the switch boxes.
This happens because the inductance of the high and low speed coils are different .The low speed coil is more effective at low rpm ,as the rpm increases the low speed coil gets to a state the it saturates and no increase in voltage is therefore obtained .The high speed coil becomes more effective because of its electrical characteristics, the high speed coil then takes over as the primary stator coil and increases the voltage output to the switch box .
The signal from both low and high speed coils is then fed to the switch box ,the existing trigger then switches the gate of the SCR(Silicon Controlled Rectifier this acts like water tap) the trigger is attached to the gate(Tap) of the SCR controlling the switching of the pulse which inputs into various components inside the switch box(I do not have a circuit of internals of the switch box) ,the switch box then sends a pulse to the ignition coil that is related to the timing of the engine.
The ignition coil then acts as an auto-transformer( as per a normal car coil) increasing the voltage at the spark plugs this is due to the windings ratio and cross dimensional size of the input an output coil windings.

I run a 1995/ 150 mercury 2 stroke black max non EFI ,new and used motors here are around twice the price they are in USA. All i am after is some technical information about the stator. I can buy a power supply or make one for around 100 dollars a stator here is over a thousand .


I live on the south china coast sea, no coast guard ,no towing ,poor vhf coverage ,many people here have had problems with stators failing causing long trips back ,in a very unpredictable ocean (thats if you have a spare engine).
Regards
Peter

 

[roscoe]

I guess in that situation and conditions, I would be running twin outboards.
Also, in my experience, coils and switch boxes go bad more often than stators, so have spares of those on board.

 

[Spycatcher2018]

I do have twins but some people don't and i carry a switchboxes on board,but most of my problems have been bad stators and triggers.
Reg
Peter

 

[Faztbullet]

There is a rectifier inside the switchbox that flip/flops off of low/high speed stator output..this is then dumped into a capacitor which is discharged into the coils when SCR is triggered

 

[sam am I]

am after is some technical information about the stator.

 

[leonreno]

If you have the capability to build what you are intent on building, maybe you could make your own stators? Sell them as back up only. How much are the materials in a stator, can’t imagine it would be anywhere close to $1000. But then again I don’t understand half of what you guys are talking about.