Mercury outboard coil replacement - finding parts

[Symo007]

Mate I have a 2001 200EFI sitting in my shed with a broken powerhead I want to get rid of it was running great untill it went bang, I will sell pretty cheap if interested as I have new engine on the way

[testlab]

You would need an ohm meter to check the resistance of each coil, remember each coil is made up of 2 windings, a primary and a secondary.
You would also need to find out the resistance specs for the coils or at least compare all the readings so see if you got an odd one.
If you're trying to get away from the dealers then you should buy a genuine Merc manual, they explain everything you will ever want to know.

Just to add to these checks.... coils often don't fail in a way a simple resistance check will show up. Often they suffer internal insulation failure and this only shows up as a breakdown in the output voltage and/or its waveform.

So although the resistance measures OK it may not work properly when in use. Sometimes the coil breaks down only after it heats up or under a high load (high speed).

Any second hand coil should have a money back or right of return warranty as there is no reliable way of knowing if its a good one until its been for a good long run.

[Fed]

Noelm, Pazz says nothing about the 'miss' being inconsistent.

Testlab, Pazz says nothing about the 'miss' only happening when hot.

OK, resistance testing is not the final word but it's sure better than throwing a set of coils at it without at least knowing what's causing the rough running.


Now stop picking on me and get down to the important things in life...

Noelm, how's the cat going, where are the pics, I hope you put the bigger motors on it.

Testlab, aren't you doing some E10/condensations test or was that someone else, if it was you how about some updates.

[Pazz01]

Hey guys

The old fella is goin to have a look at testing them on the weekend.

The miss is only when we are idling all the time. Like when we are sounding around to anchor up and sends shudders through the whole boat. Probably around the 1000rpm range.

Pazz

[testlab]

Now stop picking on me and get down to the important things in life...

Noelm, how's the cat going, where are the pics, I hope you put the bigger motors on it.

Testlab, aren't you doing some E10/condensations test or was that someone else, if it was you how about some updates.

Picking on ya???? Nahhh..... I was agreeing, just didn't want to see him get some coils without a right of return - even if it fixes the idle problem no telling they/it won't break down at speed.

E10 test.... did I offer to do that??? Its the kinda thing I'd offer to do and forget about (because I got busy doing other things) Time to search the E10 threads and see if I've tripped up

[rayken1938]

Some times it pays to go to a reputable dealer.
I have a 50hp efi merc that started to run rough and wouldnt rev out when I was up at Monduran last week.
I lifted the cowel and noticed that the bottom coil was rusty looking and decided that the chances ofn getting a replacement locally was out of the question so I put up with it.
Checked the coil when I got home and it seemed to be throwing plenty of spark and rather tham mucking around trying to diagnose further booked motor in at Wondall Road marine.
Dropped it off yesterday morning and told Brian Neville ( Owner of business) the problem and also said to give the motor a service.
Brian put the motor on the computer and said that a plug was faulty so he reploaced 4 plugs,changed the engine oil and filter ,checked the gearbox oil,greased the prop shaft,said that the water pump was fine as impeller was replaced only a year ago.
He said that he would do the lower unit and impeller at next service.
Said that the coil was only cosmetic as the bottom ones often get salt on them.
All up cost was only $185 for parts and labour.
Great to find honest dealer who doesnt rip you off with unnecessary and unneeded parts and service costs.
I was very impressed with the whole experience and who knows how much I would have spent changing parts in the dark.
Cheers
Ray

[testlab]

Some times it pays to go to a reputable dealer.
I have a 50hp efi merc that started to run rough and wouldnt rev out when I was up at Monduran last week.
<snip>
Brian put the motor on the computer and said that a plug was faulty so he reploaced 4 plugs,changed the engine oil and filter ,checked the gearbox oil,greased the prop shaft,said that the water pump was fine as impeller was replaced only a year ago.

Although I am not disagreeing with you, the computer had the diagnostic info and hence it was resolved nice and quickly.

Quite different to probems that either the computer doesn't log or happens to motors not so equipped. In which case its often back to "try this mate" and the business practices of the deaer/mechanic doing the work. They're not runing a charity but likewise customers don't want to pay for the wrong guess.

Trying the obvious and doing owner maintenance/repairs/diagnostics/elimination can avoid everyone getting pissed off when difficult problems pop up (however nothing oversomes a bad attitude by mechanic or customer).