EST ignition installation on Mercrusier 3.0L

[mrsaundep]

MCM 140, Serial number, 5568367

Good day,

Further to previous post July 11th, 2012, 01:09 PM...

I purchased the 3.0L Delco EST distributor kit from Michigan Motorz as recommended on above post by Don S.

I have finally received the parts from the States and got round to start the installation today and have a couple of questions please; I have removed old coil and distr, installed the new coil and 'distributor' mechanically.

Electrically I found that the old coil had TWO wires connected together onto the coil ?+? terminal;
- 1 purple/yellow - connected to the starter motor solenoid,
- 1 brown colour (but when I dug further into the harness it was actually a pink/purple colour) ? cant trace where it goes to as lost in the harness wiring.

I have checked the Battery voltage = it was 12.6VDC.
The Voltage on purple/yellow wire to the coil + (with Ignition key in the run position) = was 0.0 VDC!
The Voltage on brown (pink/purple under the harness) wire also connected to the coil + (with Ignition key in the run position) = was 11.4 VDC.

The Instructions from Michigan motorz only mention 1 wire purple/yellow. These instructions also state that the voltage to the EST coil ?should be 12V - battery voltage?, but that it must be more than 10.9 volts. I am getting 11.4V, but as stated my battery voltage is 12.6V. So I guess that a resistor must be fitted?

Now then, the Mercruiser manual#3 wiring diagram shows the purple/yellow wire between coil and starter motor, and a purple resistor wire. So I appear to have both these wires on the installation but I am confused as to why I have 0V on the purple/yellow wire and 11.4V on the purple resistor wire?

So, my questions are;

1). Which wire(s) of the existing purple/yellow @ 0.0V and purple wire @ 11.4V should I connect to the purple wire on the new EST pigtail plug to the coil?

2). Or, should I run a new cable direct to the coil to give full battery voltage @ 12.6V direct to the purple wire on the new EST pigtail plug to the coil? If I should run a new wire, where is the best source (location) to run the wire from?

3). Is the grey wire connected to the old distributor the tacho cable? (This is not shown on the engine wiring diagram I have from Manual #3).

I am quite tempted to experiment, but am a bit worried about blowing something up!! So I thought I would dig into the mass of experience on here yet again!

Many thanks in advance for your helpful replies...
Paul

 

[Don S]

Re: EST ignition installation on Mercrusier 3.0L

1). Which wire(s) of the existing purple/yellow @ 0.0V and purple wire @ 11.4V should I connect to the purple wire on the new EST pigtail plug to the coil?

2). Or, should I run a new cable direct to the coil to give full battery voltage @ 12.6V direct to the purple wire on the new EST pigtail plug to the coil? If I should run a new wire, where is the best source (location) to run the wire from?

The purple/yellow wire comes from the starter to assure full battery voltage to the coil when cranking. Your engine wiring harness has a resistor wire going to the coil it should be purple too. Trace the resistor wire back to it's connection to the harness and splice in a new solid wire. You do not want that resistor wire in the system for the EST distributor.

The gray wire going to the tach, get hooked to coil gray wire connector as mentioned in the instructions.

 

[mrsaundep]

Re: EST ignition installation on Mercrusier 3.0L

Thank you Don. Do I also connect the existing purple/yellow wire from starter to the new coil? or just the new solid wire only?

 

[Don S]

Re: EST ignition installation on Mercrusier 3.0L

Yes, you can add it to the connection as well.

 

[mrsaundep]

Re: EST ignition installation on Mercrusier 3.0L

I have installed the EST kit fully, including the cut out switch, set base timing, and all appears o.k on the timing front.

However, I still had a problem with idling speed, so, I bit the bullet and stripped / rebuilt the carb myself. Followed manual 3, section 4b step by step, found some crap and that one of the thin brass tubes on the venturi cluster was blocked up, see attached photo. This and everthing else cleaned up OK, and rebuilt with new rebuild kit "CARB REPAIR KIT QUICKLSILVER 823427A1".

Fitted and tested and runs o.k, but I now have a fuel starvation issue, I will start a new thread on this as it is a seperate issue and I need some help.

One thing about the carb rebuild, the manual shows a baffle "8. Remove baffle, (Figure 10)". When I opened my Carb there was no baffle fitted around the needle assemby as shown in the manaul, see attached photos. I have re-assembled the carb as I found it, without baffle. Will this cause any problems?

 

[mrsaundep]

Re: EST ignition installation on Mercrusier 3.0L

One thing about the carb rebuild, the manual shows a baffle "8. Remove baffle, (Figure 10)". When I opened my Carb there was no baffle fitted around the needle assembly as shown in the manual, see attached photos. I have re-assembled the carb as I found it, without baffle. Will this cause any problems?

View attachment 165418View attachment 165419View attachment 165420

Does anybody have any opinion/advice regarding this missing baffle?

 

[Don S]

Re: EST ignition installation on Mercrusier 3.0L

Personally, I've never left one out to find out if there is a difference or if it needs it.

One reason you won't get many answers is you changed subjects from changing your ignition system (See title of your tread) to a carb problem. Might try asking a carb question in a new thread.