Mercury 15 - trouble starting - this is cracked?

Barter · 29 June 2019, 20:57

[IMG]

custom virtual dice[/IMG]

Been having trouble starting a mercury 15hp, on inspection this part is cracked... could anyone advise on what this part is called? Many thanks

Fenlander · 29 June 2019, 21:00

They are your coils. The crack could allow the spark to leak to earth.

Barter · 30 June 2019, 08:47

Quote:

Originally Posted by Fenlander

They are your coils. The crack could allow the spark to leak to earth.

Thank you. I’m new to outboards, any idea on where to get a replacement? Simple fix? Or would I be better taking this to a specialist.

beamishken · 30 June 2019, 08:53

Prety easy to change just a straightforward swap over parts should be available from any merc dealer

Fenlander · 30 June 2019, 09:16

Looking at this again... do you mean this OB isn't a great starter or it won't start at all?

This could be your problem or it could be coincidental. You could remove the coil, clean it with a barely damp rag and dry properly it in a warm place. Then fill the cracks with silicone sealant which will insulate and see if that makes a temp repair.

Somewhere online there are electrical test figures for the Mercury 15 2-stroke ign system and you could check your coils.

There were two different colour coils fitted to this OB range. Earlier ones (say 2000 and before but just a guess) had blue coils like yours and later ones black coils. They may be electrically different but I don't know so check out before buying.

Finally note the two coils have different lead lengths. Again I'm not sure if the leads are integral to the coils or can be changed but if they are integral don't buy a short one if you need the long side... I think it is the long side to lower cylinder you are showing as cracked. You can check if the leads can be changed over I'm sure by removing the cable tie and pulling the rubber caps back.

Fenlander · 30 June 2019, 09:34

Here's than OE repair manual online... http://www.baads.org/wp-cms/wp-conte...nual_PART1.pdf

Section 2 for ign and the coil test figures are in the spec table. I see they mention a pre/post 1999 ign system change but not clear if the coils are physically different... dealer or online parts listing for your serial number would sort that. They seem to have the same test figures across those years anyway.

Info in that manual does seem to show the coil leads can be swapped if the length were wrong.

Edit: Should have asked if you've done the basic checks... taking plugs out and earthing then pulling over looking for a spark... seeing if plugs wet or dry etc.

Barter · 30 June 2019, 11:41

Quote:

Originally Posted by Fenlander

Looking at this again... do you mean this OB isn't a great starter or it won't start at all?

This could be your problem or it could be coincidental. You could remove the coil, clean it with a barely damp rag and dry properly it in a warm place. Then fill the cracks with silicone sealant which will insulate and see if that makes a temp repair.

Somewhere online there are electrical test figures for the Mercury 15 2-stroke ign system and you could check your coils.

There were two different colour coils fitted to this OB range. Earlier ones (say 2000 and before but just a guess) had blue coils like yours and later ones black coils. They may be electrically different but I don't know so check out before buying.

Finally note the two coils have different lead lengths. Again I'm not sure if the leads are integral to the coils or can be changed but if they are integral don't buy a short one if you need the long side... I think it is the long side to lower cylinder you are showing as cracked. You can check if the leads can be changed over I'm sure by removing the cable tie and pulling the rubber caps back.

Thank you for this, great help. It’s running fine once it’s going. Some times it starts first pull. Flushing it yesterday and it ran for around 10 minutes then just cut out. Couldn’t get it started after that... nothing seems seized it just can’t quote get going off the pull. I can’t seem to find the blue coils anywhere online, will another fit? I will take it off and try sealing it as you advised first though.

Barter · 30 June 2019, 11:49

I’ve searched my serial number and nothing seems to come up... it’s 09701570 - I think I could replace the part if I knew what to order ha ha.

GuyC · 30 June 2019, 13:01

It may be co-incidence but if you go to the following website:

Marine Engine Parts, Spares & Repairs | Holes Bay Marine Poole, Dorset

you can select Mercury and 15 and then if you ignore the first zero, your serial number does seem to fit an available serial number range.

I've never used them but I'm looking round for a spares kit for my 15hp Mariner and happened on this website.

Fenlander · 30 June 2019, 16:05

Had a look at the Holes bay parts listings. Seems whichever of the serial number ranges of the mid 1990s on models you try be it a 15, 9.9 or XR10 they all come up with the same coil part number at about £46 plus VAT.

As you say you will do I'd really want to try re-sealing the existing coil as a test first as I'd have expected it to cause perhaps rough running/idle or a misfire if intermittently earthing through the crack... but not cutting out totally after ten mins as it should just be capable of chugging along on one cyl.

There are so many things that could cause your problem such as heat soak failure of flywheel coil/CDI unit or the fuel system blocking (tank bleed open and OK?) or pulling in air.

jeffstevens763@g · 30 June 2019, 17:37

Personally I would clean the crack then run a soldering iron down the crack see how it goes

Barter · 30 June 2019, 18:53

Thank you all for the excellent advice. I’ve looked back on pictures from the listing of which I bought it from, it actually had a cracked coil then which I hadn’t noticed (engine seemed to work fine then) I’ve taken the cowling off again just now, and inside there is visible water and fuel/oil... maybe a bigger problem than I first thought! I think I am out of my depth with this so will take it into a dealer next chance I get. Thanks again everyone.

Fenlander · 30 June 2019, 20:31

Oh that's a shame. Water coming from the engine in that location could be as simple as the pee tube connection or thermostat gasket and if getting into the cracked coil would obviously cause problems.

Oil misting could be a loose spark plug or both oil/water could both be a failing head gasket which is super easy on a 2-stroke.

Do report back on what the dealer finds.

beamishken · 30 June 2019, 20:33

The moisture is likely just condensation which could explain the bad starting. Moisture + a cracked coil will likely equal no spark until the revs get up a bit when starting on the good cylinder
But if your not confident then maybe a trip to the dealer is in order.
On the other hand a cracked coil isnt going to heal up so you have nothing to loose by changing it first. even if it doesnt cure the fault it needs replacing or it will be a fault at sometime

jeffstevens763@g · 01 July 2019, 10:33

might be an ill fitting cowl seal i notice rubber on the first picture near the catch and quite a bit of water near the tell tale in that area. my advice would be to fix the crack WD 40 to get rid of the water and clean up get an hair dryer on it and go again see what happens before spending money

beamishken · 01 July 2019, 11:00

Quote:

Originally Posted by jeffstevens763@g

might be an ill fitting cowl seal i notice rubber on the first picture near the catch and quite a bit of water near the tell tale in that area. my advice would be to fix the crack WD 40 to get rid of the water and clean up get an hair dryer on it and go again see what happens before spending money

Surely the best advice is replace the obviously damaged coil? It won't heal up and is likely to become an issue when you least want it to. Why would you advise bodging up a critical ignition component?
Even if its not his current issue it needs replacing before it becomes his next issue.
And it might just be his current issue.
If the engine is leaking water and spraying under the hood a run with the hood off should show the source of the leak. On the other hand unless its condensation on the engine it shouldnt be wet at start up as presumably it would have dried out during storage

jeffstevens763@g · 01 July 2019, 12:11

because a temp repair and drying out will give him chance to sort the water issue new coils will still be affected by water spraying over them once the water's sorted then go for a permanent repair

Fenlander · 01 July 2019, 12:34

I think we have all got slightly different ways of going about this were it our own OB and they are all valid. It's just frustrating that it's not in our yard with the opportunity to check it over with benefit of experience.

jeffstevens763@g · 01 July 2019, 13:00

Quote:

Originally Posted by Fenlander

I think we have all got slightly different ways of going about this were it our own OB and they are all valid. It's just frustrating that it's not in our yard with the opportunity to check it over with benefit of experience.

my angle is the OP says he knows nothing about outboards which is fair enough and says he's thinking of taking it to a dealer thats where the money starts i was guessing the engine ran ok when he bought it until the water appeared if it is just splash from the cowl or there's the tell tail pipe spraying water thats easy to fix for him or if there's a gasket blown then he can set about buying a new coil & getting the gasket replaced i just think get it running to see where the waters coming from before jumping in spending dosh

Fenlander · 01 July 2019, 13:05

Yep I agree Jeff and were it me I'd have it in the tub on the back yard doing just that... and that's what I mean about frustrating when you know you'd get to the bottom of it quite easily but can only do so much advising at a distance.