Replacing the whole electrical system

[mattmann1972]

Hi

I have a 50HP Merc Brown Band 1985 4 cylinder serial number 9421064.

There is no spark at the plugs and on testing i think the Blue wire circuit in the stator has gone which is causing the problem, i understand this is the low speed part of the stator which is why there's no spark.

I've tried hunting for a stator for this motor here in the Uk without joy so i'm looking on ebay in the USA and i see that they are plentiful.

Now due to exchange rates i see that parts are a lot cheaper in the US so i'm tempted to replace everything, Stator, Trigger, Rectifier, Coils, Plugs and leads.
Hopefully i'll be able to pick these items up for somewhere south of $350 delivered.

I have a manual on order at the moment and am pretty mechanically minded but is there anything i need to be worried about before undertaking this replacement operation and should i consider any other parts too?

Matt

Weymouth, UK.

 

[pnwboat]

Re: Replacing the whole electrical system

I think you've got it all covered. I would caution you though about replacing everything, especially with used components. The old saying, "If it's not broken, don't fix it" has come back to haunt me several times in the past. The CDI replacement components (stator, triggers coils etc) generally have a good reputation. Just make sure you note where all of the wires connect, and double check the ignition timing (important if you change the trigger) when you're done.

 

[mattmann1972]

Re: Replacing the whole electrical system

Hi

Yeah i will make sure and take an awful lot of photo's before hand.
I'm gonna replace the stator and trigger with new parts rather than used, i don't want to get caught out in the Portland race with a failed engine! (The UK's equivilent of the cape of good hope!)

Matt

Weymouth, UK.

 

[j_martin]

Re: Replacing the whole electrical system

Hi

Yeah i will make sure and take an awful lot of photo's before hand.
I'm gonna replace the stator and trigger with new parts rather than used, i don't want to get caught out in the Portland race with a failed engine! (The UK's equivilent of the cape of good hope!)

Matt

Weymouth, UK.

You said "I think it's.........."

My recommendation is if you are going to spend that kind of money, start with good documentation and test equipment. You should be good to go with a factory service manual and a good DVA.

With good diagnostic practice, you replace the bad part. If you keep records of your diagnostics, you can identify trends, and maybe even prevent a failure when it counts.

The trouble with the shotgun approach is that you are likely to introduce one or more new problems, and then baffle yourself.

Good documentation and test equipment also sets you up to make small performance adjustments and immediately examine the results, and leave yourself a way to take that step backwards if it doesn't do what you expected.

hope it helps
John

 

[mattmann1972]

Re: Replacing the whole electrical system

Hi John

Thanks for your comments. I have a good DVA but until i install a new Stator i guess i won't know 100% that this is the problem, heck it could even just be a bad wire connection. Do you recommend that i should just start off by buying a new one of these and go from there? My only concern is that as i'm buying from overseas it'll take at least a week between each delivery should i then need a trigger etc.

My symtoms are it won't spark at the plugs and there is a strange resistance between the blue and blue/white wires on my 50HP Merc Brown Band, 4 cylinder, 1985 serial number 9421064.

Matt

Weymouth, UK.

 

[j_martin]

Re: Replacing the whole electrical system

Hi John

Thanks for your comments. I have a good DVA but until i install a new Stator i guess i won't know 100% that this is the problem, heck it could even just be a bad wire connection. Do you recommend that i should just start off by buying a new one of these and go from there? My only concern is that as i'm buying from overseas it'll take at least a week between each delivery should i then need a trigger etc.

My symtoms are it won't spark at the plugs and there is a strange resistance between the blue and blue/white wires on my 50HP Merc Brown Band, 4 cylinder, 1985 serial number 9421064.

Matt

Weymouth, UK.

Right now, with a DVA you can test the stator and trigger. They are independent of each other. If the trigger looks good, just buy the stator.

You need good stator power to the switchboxes to go beyond that.

Stator replacement shouldn't change timing, but trigger would. You need more tools to properly set up the linkage and timing.

hope it helps
John

 

[mattmann1972]

Re: Replacing the whole electrical system

Thanks for the tip, ok i may just try the stator and go from there.

Matt

Weymouth, UK.

 

[mattmann1972]

Re: Replacing the whole electrical system

OK, i've just ordered a brand new Stator, Trigger, Plugs and Leads from Don at outboardparts.com who was very helpful indeed.
I'm only going to change the Stator and plugs to start but i will have a trigger should i need one.

It's crazy how we Brits get ripped off here in the UK, if i bought a Stator alone from a local agent i would have to pay $500 just for this part! I managed to pick up all the above from the USA for $285 including delivery!

Matt

Weymouth, UK.

 

[mattmann1972]

Re: Replacing the whole electrical system

Just had a thought that perhaps i should also replace some of the other wires going to the switchbox, what grade and type of wire should i use? I'm guessing traditional copper wire's not up to the marine enviroment?

 

[j_martin]

Re: Replacing the whole electrical system

Just had a thought that perhaps i should also replace some of the other wires going to the switchbox, what grade and type of wire should i use? I'm guessing traditional copper wire's not up to the marine enviroment?

UL1426 is the wire specification. It is stranded a bit finer than automotive primary wire, and has tin electroplating on it and fire resistant insulation sometimes called self extinguishing.

Putting a crimp on connector on this wire would totally negate any improvement possible with the superior wire.

I have found a trick when terminating marine wiring. I cut the insulation clear of the terminal end of the crimp sleeve on a heat shrink connector. Then I hold the stripped wire vertical in a little vise, set the connector on it. Solder the connector with eutectic resin core solder (electronic high grade stuff) When you solder the connector, the heat shrink plastic will flow over the solder. There's a bit of timing to it, but it's not critical. Heat shrink the connector insulation and you have a marine grade connection.

You can use an uninsulated connector and adhesive lined heat shrink and make a very high quality soldered connection also.

I've never had a failure in one of these connections. Crimped, on the other hand, is a circuit failure in planning.

BTW, I would warn you against shot gunning a bunch of changes in at one time. You can put in a secondary fault that could baffle you. (ask me how I know)

hope it helps
John

 

[mattmann1972]

Re: Replacing the whole electrical system

Cheers John

I'll see if i can source some of that wire in preperation for when the stator etc turn up mid next week. I'll let you know how it all goes.

Matt

Weymouth, UK.

 

[mattmann1972]

Re: Replacing the whole electrical system

Ok, the parts have just arrived from the States (thanks Don) in exactly a week after ordering. The weathers a bit crap here in the UK at the moment so fingers crossed they'll be a break from all this rain over the weekend so that i can fit the new stator, plugs and leads. Even though i have a brand new trigger here i'm not going to fit this at the moment, lets just see if the stator does the trick first!
I'll post back once it's done! Wish me luck!

Matt

Weymouth, UK.

 

[RaScLeS]

Re: Replacing the whole electrical system

another well detailed thread. very nice good luck !