3 requirements for proper ignition (140)

[SSTKO81]

Good morning everyone! HOpe your 4th of July was great. Mine was dry, as my boat sat on the trailer rather than the blue waters of my local lake. The problem? No ignition. I didn't have a very good spark, which led me to believe the coil was weak (the old one was leaking oil from inside the terminal) but I replaced it and that seemed to help. but still no ignition. I cleaned the plugs. -nothing. I checked the wires -nothing. I made sure the carb was working, choking, breathing, etc. -nothing. So now i've got spark, fuel and air.... Someone suggested points, but ive replaced them with the pertronix system. When I installed it I DID NOT use the "diode fix". But I tried it and still nothing. I guess my timing could be off, but it should still at least try to start... Is there a resistor line going to the coil that should be replaced? I'm losing my mind here... Anyone ever seen this before?

 

[stonyloam]

Re: 3 requirements for proper ignition (140)

With the ignition switch on, measure the voltage at the + terminal of the coil. Should be around 8-9 volts or so (don't know exactly) voltage at the choke end of the coil wire should be 12V . If voltage is OK, you are not going to like this If you have the old points, put them back in and give it a try.
P.S. My Pertronix ignition is in the boat glovebox, I think

 

[jagilbert]

Re: 3 requirements for proper ignition (140)

The voltage at the positive side of my coil is 4.5 volts. Im pretty sure that is within spec. if you have a normal coil that has a resistor wire.

Make sure the red wire of the Pertronix is connected to a full 12v switched source, NOT to the plus side of the coil and the black wire goes to the coil (-).

Make sure you didn't forget the rotor. (I know - duh, but I've done it).

yeah, try the points again, at least as a troubleshooting step. I love my Pertronix.

 

[Kainon]

Re: 3 requirements for proper ignition (140)

Hm.. I love my Pertx, and have 12v switched going to the + of the coil and haven't had any issues, though I think I might change that.. ( yea it likes 12v better but can run on the 9v @ the coil. )

 

[SSTKO81]

Re: 3 requirements for proper ignition (140)

I gave the points another try with no success. In fact somehow along the way the wire from the condenser to the coil got crossed with a positive test lead and I had a fun little electric fire. But that's the only fire I had Cause the engine is just not crankin up. Could this be a timing issue? Again I've got spark, not real strong but id think it's enough to fire. ):

 

[tschmidty]

Re: 3 requirements for proper ignition (140)

It could definitely be a timing issue, or not (helpful, eh?). Can you pull a spark plug, ground it and see the spark when you crank the ignition? Double check the timing to make sure it''s close enough to fire (rotor on #1 plug should see timing mark close at least). Double check the firing order too.

 

[SSTKO81]

Re: 3 requirements for proper ignition (140)

ok, here it goes. Spent the day working on it today with little success but learned quite a lot.
1) The Merc 140 has a label that says engine rotation its CCW (counter clock wise), this must be the direction when looking at the crank, because mine turns CW.
2) Since the enging was CCW I thought that meant the dist. rotor turned CCW. -no.... It too turns Clockwise, so all my wires were backward but one
3) When you order a Pertronix unit online you get to choose a unit that is clockwise (standard 91145A?) or a CCW unit (91146A?) of course I got the CCW one...
4) Don't go to Autozone if you need a cap or rotor for you Mercruiser. They'll look on their little computer for an hour and if they cant figure out what kind of CAR it might have come out of they'll just send you to OREILLYS. They were able to do a couple cross references and in 5 minutes I was out of there with my parts in hand. (thanks guys)

So after realizing all my other boo boos in wiring and replacing the cap and rotor and primary wire from the coil to the cap I realized I was only getting spark to the 3 and 4 cylinders. So I called Pertronix and after hanging on hold for 10 minutes I was informed; yes, I have the WRONG ignitor II system. But they were good enough to send me a new mounting plate for the module free of charge and it should fix me right up. (thanks pertronix) So the moral of the story is: For God's sake if youre gonne spend $120 bucks on an electronic ignition at least order the right part and make sure your engine is turning in the right direction.
(more life lessons to come later)

 

[SSTKO81]

Re: 3 requirements for proper ignition (140)

Follow up! Still not working out right. I got the new 91146 mounting plate from pert, which was supposed to fix my problems. Wrong. I'm still Only getting spark to the 3rd and 4th cylinders. I double checked my firing order and that everything from the distributor to the block was in the right order (1,3,4,2 in a clockwise motion, right? Cylinder 1 is at the front still...) still not starting. I'm at a loss. Help! Vacations only a week and a half away!

 

[dingdongs]

Re: 3 requirements for proper ignition (140)

just a hunch and it may be a long shot but the shift micro switch is designed to earth out the ignition circuit when changing into forward or reverse but if yours is faulty it may give you the problems your encountering.put a circuit tester across it and test for a normal open circuit.

 

[SSTKO81]

Re: 3 requirements for proper ignition (140)

Its worth a try at this point. I went back and rechecked spark at the coil and its very stong, so somewhere between the coil and and distributor theres a breakdown... I doubt its the wires, as their only a year old and in good condition. the cap and rotor are brand new, as I was having the same problem with the old ones... So how do I explain spark to only the 3 or 4 cylinder? Its like the timing is just off or something, but I havent touched it.

 

[Skybreeze]

Re: 3 requirements for proper ignition (140)

Have you got the right rotor or is it old. I have just fixed my boat were the rotor was so badly worn down that it was dropping off one cylinder. Yours could be worse than mine or if its the wrong one the gap could be too much for the spark to jump. Just a thought

 

[SSTKO81]

Re: 3 requirements for proper ignition (140)

Ha! sucks when that happens, but unfortunately its not the case here.... Mine are new and were replaced because I thought they could be the fault of my woes here. (guess not) I was reading a post from about a year ago and a member (whs109) reported similar problems with his ignition kind of randomly selecting when to fire. Turns out the mag ring wasnt seated well on the distributor shaft. So he would get spark on 1 but not two, fiddle with it and get spark on 3 and 4 but not 1 and 2, etc. Tapped the mag ring down and boom! instant fix. Is this a common problem with these systems? (don't worry I'll rebuild my burned up points/condenser and keep them as spares)

 

[dingdongs]

Re: 3 requirements for proper ignition (140)

is the shaft of the dissy rocking from side to side /turn engine over without any plugs in and cap off and see if points are sparking.try also in pitch black and see if you have earthing.new plugs a must.

 

[SSTKO81]

Re: 3 requirements for proper ignition (140)

Did A check of the plugs. All good except one needed the gap reset. I'm wondering if I've got the wrong kit from Pertronix. Every reference Ive found says I should be using the 1146A. I'm gonna go tinker with it more and see what happens if anything.

 

[SSTKO81]

Re: 3 requirements for proper ignition (140)

No better. Still only getting spark to the number 3 cylinder. Tomorrow is my day off. So I'm goin down to Oreilly's with the VISA and an attitude and I'm gonna buy out the place till i fix this issue. (or maybe I'll just get some new wires and digital volt meter; and one of those little pine trees that smell like the ocean.)

 

[SSTKO81]

Re: 3 requirements for proper ignition (140)

-feel like i'm just talkin to myself now... has anyone ever heard of the lobes on the distributor shaft being out of round effecting the trigger on the pertronix unit? One mechanic I spoke to said that was his opinion, but it didn't make much sense to me since there is a mag sleeve that sits over the lobes. So unless the ring is spinning freely (its not) it shouldn't make a bit of difference if the lobes are a little rounded. Right?

 

[snlgraham]

Re: 3 requirements for proper ignition (140)

Im not a real mechanic but I have a 140 mercruiser that had ignition problems. Twice I have had a similar problem just not getting spark. The solution was very simple and made me feel really dumb after going around and around and replacing parts. It was a low charge on the battery. Just not enough voltage to keep the high performance coil consistant. My battery was low from all the cranking and testing. If this was a car it probably would have started. Just a shot in the dark, but top off the charge on your battery.

 

[bigskiohio]

Re: 3 requirements for proper ignition (140)

4.5 v seems low especially for breakerless ignition. you dont need the resistor wire do you.

 

[SSTKO81]

Re: 3 requirements for proper ignition (140)

mine wasnt test at 4.5 v. it was closer to 10. spark from the coil is pretty good. its just not making it past the 3rd cylinder for some reason. My coil says it needs the resistance wire, or I'd just change it out. If things to get fixed soon i will

 

[essveedub]

Re: 3 requirements for proper ignition (140)

I have a pertronix ignition in my 1976 140 mercruiser as well. I also currently have no spark. In my troubleshooting, I found that I was getting around 4.5 volts to the "+" side of the coil with ignition on, and the resistor wire would heat up to the point that it's almost too hot to touch (tore off the wire wrap to see if I was shorting or something - this all before I knew about a "resistor wire"). With the pertronix wires unattached, I would see +12 volts on the plus side. I assume this is due to the resistor wire bypass from the starter solenoid, or i don't actually have a resistor wire. The bypass should only work when cranking?
Anyway - I was thinking the coil was shot. But then I decided to check out the pertronix unit - and found a bunch of shredded plastic - the magnet wheel was rubbing on the sensor. My assumption is that the sensor is shot (not to mention the magnet wheel - source of the plastic bits - sensor has a slight rubbing mark), and that was making reason for the low voltage at the plus side of the coil. It looks like you're getting the 4.5 volts with a good ingition unit? maybe my sensor is not the issue... but from what if seen on this forum and others is that it should be at least 8-9 volts with resistor /12 without. I can't see 4.5 being enough to for the coil to produce a spark.

Anyways, i've found the pertronix trouble shooting (http://www.vintageperformance.com/retrorockets/field_test.htm) and will see if my original sensor is in bad order. But, since I don't have internet access at the cottage, I didn't test it at the time, and I went ahead and ordered a new pertronix unit (1146A) and a Flamethrower coil (40611 - 3.0 ohm epoxy filled). I plan on bypassing the resistor wire and connecting switched 12 volt straight to the new coil and pertronix sensor. I can't see how this will not produce a spark now...??

Oh and I will make sure to properly adjust the gap between the sensor and magnets this time