Evinrude v4 90 ignition issue (1987)

[Refugee]

I am at my wits and budget end. Are there any bright sparks out there that can advise on why I do not have a bright spark.
Cyl3 refuses to produce a spark.
I thought it was ignition coils so bought a couple of new ones...no change
I thought it was the power pack so bought a new one...no change
I thought it was the stator so bought a new one...no change
So some serious money down, the missus giving me the evil eye and I still do not have spark in Cyl 3. It does come on intermittently, and normally when cold.
My last port of call is the rectifier/regulator pack. Is there any way this could malfunction in such a way that spark is fine on 3 cyls but not on 1? Seems unlikely to me but I will clutch at any straw.
Any advice?

[Chimo]

Can see why your at your budget end; probably easier and cheaper to go to an OMC / Bombardier Marine Tech.

Where are you? We on here know some good ones.............

Cheers
Chimo

PS Had a V4 90 OMC, very nice motor :-*

[FishHunter]

Instead of replacing nits willy nilly its a lot easier to swap stuff around and see if the fault moves with the component so as to prove which component it is. Have you also replaced the HT lead between coil and spark plug? If not I would swap with one from another cylinder to test it as that is the most likely cause of your problem.

if its only 1 cylinder being affected then it cant be anything on the crank unless that motor has a seperate pickup for each cylinder(highly unlikely)

[Fed]

The rectifier/regulator has nothing to do with the spark so don't change it.
How did you test for spark?

[STUIE63]

it's a dumb question but have you replaced the plugs

[Refugee]

Thanks for the replies. I have changed spark plugs and HT leads. Chimo, I am in Brisbane West.

Checking for spark a number of ways.
1. Using a spark working plug whilst the motor is running.
2. You can feel when the cyl 3 stops working...total lack of power
3. Pulling each HT lead off whilst engine is running. 1,2 and 4 has noticeable difference if the engine continues to run at all. pulling no.3 has no effect.
So Fed you dont think the rectifier could be the cause then?
Shaun

[Fed]

Checking for spark a number of ways.
1. Using a spark working plug whilst the motor is running.
I don't understand this Shaun?

Are you calling #3 the bottom Port cylinder?
If so then check your fuel pump pulse line for air leaks and also pump up your primer bulb and check the pulse line for fuel leaking through a tear in the pump diaphram. There should be no fuel coming into the pulse line.

If you're 100% positive it's a spark problem then any decent OMC guy should be able to diagnose it very quickly & far cheaper than you could get the stuff needed to do it yourself.

The rectifier/regulator won't any effect on the ignition it's a completely different system.

[Chimo]

Refugee

Earlier posts on other threads have suggested Downes Marine (although I've no personal experience with them as I use Ski and Race Marine down here) i.e easier and cheaper to go to an OMC / Bombardier Marine Tech than keep on buying bits you possibly don't need.

Cheers
Chimo

[Refugee]

Hi Fed,
I am calling #3 the top starboard cylinder.
I should have said I use a spare working spark plug on the #3 HT lead when the engine is running so I can see the spark. The #3 spark plug is still screwed in so I dont damage anything.
Thanks Chimo. I have been to Downes before. May have to give it another go.
At least I gather that the regulator/rectifier cannot be the cause. I did the test and got infinity both ways so though it was a goner.

[Refugee]

I should also mention my tach has a mind of its own too. Another reason why I thought it could be the rectifier/regulator.

[FishHunter]

I assume you are grounding the earth strap of the plug while you are checking for spark?
Regulator/ rectifier is for the charging system not the ignition system.
These are the steps I would follow to diagnose a missfire.

1 Check for spark, if no spark
2 Verify power and ground at ign coil if good
3 Swap spark plug with a KNOWN good plug ie from another cylinder that runs properly if no change
4 Swap HT lead with a KNOWN good one from another cylinder if no change
5 Swap ign coil with a KNOWN good one if no change
6 Check wiring between ouput of ign module and coil. if ok
7 Check output of ign module with oscilloscope, noid light etc

By now you should have found your fault. Just because something is new or supposedly working doesnt mean its actually working hence my emphasis on KNOWN good.

[Noelm]

just measuring "stuff" with a meter is useless unless you know what you are measuring for, do yourself a favour and buy a genuine manual for your model, by now it would have saved you a few hundred dollars and a lot of time, the rectifier will probably be the cause of your tacho having "a mind of it's own" and I doubt it will be the cause of your perceived no spark on one cylinder, but as the old saying goes, "you never know" trouble shooting requires methodical and correct procedures or you may end up with a few more faults to chase later on.

[Steeler]

If it is one of those stupid recs that sit under the flywheel semi submerged then as Noelm said it will be shot if your tacho is erratic, a very common problem on those.

How are things down in Gods country Noelm ?.

[Gon Fishun]

Checked compressions???

[Refugee]

Thanks everyone. Reckon I have to spend a bit more time troubleshooting this from scratch again.

[Noelm]

Do you have a manual for your motor???

[Refugee]

Hi Noel,
Yes I do have a manual. I have used it quite a bit during this excercise as it is quite good at detailing tests etc.

[Noelm]

OK, it is a GENUINE OMC manual?? not a generic like Clymer, the genuine maual will have precise step by step trouble shooting, follow the steps start to finish, it is a simple motor and I am somewhat puzzled about the one cylinder spark business, my thinking is some sort of corroded wire in one of the plugs.

[lee560]

Try running it at night with the cowling off and if the lead is buggered you will see it earth and spark from lead to something metallic close to it . Failing this rest a screwdriver across the lead and earth it, if it sparks at the end of the screwdriver the lead is breaking down.

[BM]

To start with, top right cylinder is no. 1

Ok, you mentioned you have spark intermittently on 3(1) usually when cold. This sounds indicative of a temperature/resistance related problem.

If you have confirmed that you have good plugs, leads are good, coils are good, power packs are good and stator is good then you really only have one component left and that is the trigger windings (also under the flywheel).

The stator cannot have been the problem as it simply charges the power packs. It's the trigger plate that triggers the power packs to fire. Pretty unusual for an OMC stator to fail and eve moreso for a trigger failure but if does happen.

The rectifier/regulator should have nothing to do with your problem as its simply taking the AC waveform from the stator and rectifying it to DC and regulating it and putting it back into the battery. Erratic tachos are usually tacho or wiring related but can also be affected by a malfunctioning reccy/regulator. Usually the reccy/reg dies and thx tacho dies along with it.

You can check your reccy/reg by checking battery voltage, run engine at say 1500rpm and recheck voltage. A fully charged battery is 12.6V (standard type cranking battery). You should be up around 14v.

Try firing no 4 (the cylinder below) through no 1's coil. That will verify theres no problems downstream of the coil. But if that has a new power pack in that side I think barring some other weird arse issue you have a crook trigger.

Cheers

[Fed]

Standing in a puddle of water trying to earth a sparkplug to the block of a running motor putting out 50,000 Volts is not a good test.
Pulling a lead and seeing no change only means that cylinder is not working, could be anything refugee.
Spark, compression, fuel/air, water.
iboats is a good source for things like spark testing and peak voltage testing.
It's a shame you forked out for all those parts but if I ever need them I'll know who to ask.
I've got a 1988 along with the OMC manual so if you're using a Clymer and need to confirm anything just ask.

[Spaniard_King]

proly just a dud lead I recon

[Refugee]

Back to basics then. I'll start with lead and progress up the chain again. I'll try the night running and check for sparking too. If I find the issue I'll post back here. If not, wonder how much I can get by selling the engine for parts :-)

[BM]

Try firing no 4 (the cylinder below) through no 1's coil. That will verify theres no problems downstream of the coil. But if that has a new power pack in that side I think barring some other weird arse issue you have a crook trigger.

Cheers

That should have read 'no. 3' not no. 4

[Refugee]

OK, hope you guys can check my findings. Problem still exists so while on the water this weekend I started troubleshooting and feel it may be my timer base. Checking the Ohms which should be 38-43 ohms between the white and other wire I found that to a blue wire it fluctuates between infinity and 150ohms as I wiggle the wiring loom close to the base.
Could a faulty timer base cause no spark on 1 cylinder? Thanks all.

[BM]

Follow the tests in your manual and if the trigger/timer base is out of the designated range mentioned then it's shot.

As a secondary check, take no 3's coil input and feed it into no. 1's input and check that you get spark on no. 1. This confirms the coil and lead and plug are ok on no. 1. You could also switch power packs to confirm the pack is ok also but given its new and so are other components it is kind of pointless but worthwhile in some regards.

Cheers

[Fed]

Your #3 is really #2 (top port side) and guess what, the blue wire feeds that one.
Providing you tested with the wires securely touching the socket holes then 150 Ohms to infinity is no good especially if it jumps around when you move the lead.
BTW the resistance of the sensor coils should be 40 Ohms +/- 10 Ohms with no earth continuity with the plug removed.
Sounds like you're using a non genuine manual.
If you want to do repairs yourself you need the genuine manual, the right test equipment and the right tools, they all cost $$$ which is something to weigh up.
Do you have a tension wrench, flywheel strap & flywheel puller, seriously reffo sometimes it makes better $$$ sense to get "the guy" to do it.

[BM]

Your #3 is really #2 (top port side)

No, he mentioned earlier that his "no. 3" was top starboard cylinder - no. 1.

[Fed]

21
43

As far as the circuit diagram goes and blue to #2.
You're right BM I think I confused myself LOL, so that makes the ohms reading crazy.

[BM]

Lol. I think the initial description calling it no. 3 set this thing in motion! Lol

[Refugee]

FIXED:
So an update to provide closure to this thread in case others come across a similar issue in the future.
I ordered and received a timer base and fitted it this week just in time for a water test on ANZAC Day. Woohoo it worked perfectly. So my original issue of no spark on 1 cylinder, be it #1 or #3 :-), was due to a faulty timer base.
Thanks to everyone who responded with their ideas and advice.

[Fed]

Good feedback Reffo, please tell me your flywheel mating surfaces were perfectly clean & dry, your key was put in with the outer face parallel to the crankshaft centreline, you applied sealant to the flywheel nut and you torqued it down to the recommended 105 Ft Lbs I think?

Don't mind me mate I'm just a worrier, really happy you got to the bottom of it.

[Refugee]

Hey Fed.
Need to remove the flywheel again soon to replace the regulator/rectifier so no sealant. All other boxes ticked :-)