coil issues??

whacker1982

i have a 35hp selva outboard, i have no spark form either of the plugs, ive put a multimeter where the plugs go into each coil and turned it over, in one coil there is no show of power reading form the mulitmeter, on the second coil its reading 10+ volts, but there is still no spark. plugs seem to be fine, old but clean looking. any ideas on both coils? thanks

fergal.b

You might get some basic info here that will help http://smallengineinformation.com/?page_id=413

Is it a 2 or 4 stroke as some of the selva engines are the same as yamaha.



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whacker1982

thanks fergal its a 2 stroke

Daibheid

That's the high voltage end of the coil and your multimeter isn't able to read the thousands of volts you should get there and in any case it's momentary so gone before your meter can see it. You need a peak voltage meter or Peak Voltage adapter for your multimeter.

A better approach is to measure the resistance on the input low voltage side. You really need the workshop manual for the engine to know what those readings should be but having two coils gives you a reference and it's unusual IMHO for two coils to go together. Also check the resistance from all terminals to ground to see if any circuit has shorted.

After that you're working back up along the line to the Stator, the trigger and the CDI unit getting technically harder to check very quickly and a manual will be mandatory. I'd check it with known good plugs and crank it in the dark with an ear close to the coils/leads - I've found that a great way to find High voltage leakage that I'd never have suspected. But if you get your ear caught in the starter ring.......

breghall

I faulty kill switch ( thing your red lanyard connects to, if you have one) will also give a no spark issue. Can be tested by removing it from the CDI unit.

have you a wiring diagram for your engine?

whacker1982

I don't have any manual for this engine, I disconnected the stop wire and got the same result. This is foreign territory to me.

breghall

whacker can't really help you here without a wiring diagram and voltage specs. Take a few pics of all electrical bits and bobs and of the tiller/remote control internals.

Fergal usually has a gift for finding manuals and stuff buried in the depths of online info, maybe he'll can find the 35hp manual..

whacker1982

breghall wrote: »

whacker can't really help you here without a wiring diagram and voltage specs. Take a few pics of all electrical bits and bobs and of the tiller/remote control internals.

Fergal usually has a gift for finding manuals and stuff buried in the depths of online info, maybe he'll can find the 35hp manual..

Cheers bregall, was in contact with selva in the uk, they were saying that they are fitted with a bosh ignition and don't manufacture them anymore, it's an old engine. Did a compression test 130psi - 135psi, really clean looking. There is very little wiring to her I'll upload tomorrow.

whacker1982

the guts and intestines of this outboard:)

whacker1982

it looks too small to be a 35hp on the front of the cover is a 20 and on the back of the cover is a 350.

breghall

One problem could be the damage to the bottom coil in pic 614. Cracked or damaged coils tend to malfunction as it's a way for the charge to escape. Also is there any damage to the flywheel magnets ?

I am not too familiar with this ignition type, but I reckon if you definitely have no spark then I'd seek to change the black ignition coils to the plugs.

No harm in dropping an email to http://www.selvamarine.co.uk with your issue.

whacker1982

thanks breghall, the fly wheel magnets are perfect, i emailed selvamarine they said they dont manufacture parts for the old selva outboards anyomore. i sent them a picture of the coiils and plug leads

whacker1982

just had had a look at the damaged coil, there is a crack going all the way round the coil, this is the same coil that is giving no reading. i put over the crack the metal putty maybe it might help?

fergal.b

Just make sure the putty is not conductive, you might be better off with epoxy resin. The newer type of coil is red but I don't think you can mix them, can you see a code number on yours.
This might also be of help. http://www.allpa.nl/media/files/manuals/Selva/USER%20MANUALS/Owner's%20manual%20Izmir-Naxos.pdf





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whacker1982

i dont know how you found this fergal, thank you. its pretty much the same wiring as mine, looks like a maze but ill check it out and see if anything is a miss with mine.

whacker1982

Ok wiring and earths checked all good, I took off the metal putty and sanded it completely off and put on the epoxy. Put it all back together turned it on, while using the multimeter and now there is a reading of 10 to 11 volts on each part where the plugs go in. This is good I hope. But there still is no spark. I'm wondering could it be as simple as the plugs?

fergal.b

I'm not sure where you are testing it from but as was said before where the plugs go into the cables you could be getting anything from 5,000 to 50'000 volts :eek:
You can buy little spark testers for a few quid that light up if there is a spark they just fit over the plug and onto the lead, this will tell you if you are getting a spark to the plug but will not tell you if you have a bad plug.