Why am I blowing condensors

[Capt.P]

1988 2.3L Omc Cobra<br />Mod # 232AMRGDE Ser # T0588261<br />Mallory Distributer, Blue Streak points<br />Hi everyone I've been reading the forums for some time now but this is my first post so here it goes.<br />I bought the boat last year and the previous owner told me it went through points every 10-12 hours of running, so I did some research and was told by the local omc mechanic that you have to use original mallory condensors with these engines not the generic ones you get from the auto parts store.So I thought it made sense and installed it (it said it was omc on the bag it was in)anyways my points didn't burn out after 10 hours the condensor did,so from what i've read on here they go bad sometimes so i didn't think much of it but now after 10 hours or so this one blew, what's up??To get me home luckily I had one from the autoparts store and mind you it runs just fine but whats causing these to blow??Should i stick with this one or get another from the marina?They charge me $18 compared too $4 at the autoparts store.Haven't had a problem with the points though!!

 

[Don S]

Re: Why am I blowing condensors

With a points system, you need either a resistor wire or ballast resistor going to the coil. If neither of those are there, the coil should have an internal resistor.

 

[Bondo]

Re: Why am I blowing condensors

Welcome Aboard Paul,........<br /><br />My 1st Guess is that you've got a Full 12 Volts going to the Points,..........<br /><br />That should be Resisted down to 7/9V or so........<br /><br />Good Luck,.....The OMC Guys will be along shortly,......

 

[Capt.P]

Re: Why am I blowing condensors

Thanks for the Quick reply!Yes Ihave a resistor wire resistance is within the range according to my Omc manual, alternater bench tested 14.4 volts disconected the wire from the solenoid to the coil temporarilly but I still get 11.4 volts at the coil engine idling battery voltage 14.4 Again thanks for the reply

 

[Bondo]

Re: Why am I blowing condensors

Battery Voltage should be more like 13.6V......<br /><br />That would lower your Points Voltage,.......<br /><br />Sounds like a Voltage Regulator Issue...........

 

[Don S]

Re: Why am I blowing condensors

If the battery is a little low, it's going to charge at 14.4 volts till it's fully charged, then it will drop down to 13.6.<br />11.4 volts going to the coil while the engine is running is too high, and without a DVA meter it's not an accurate reading anyway if the engine is running.<br />Shut the engine off, turn the ignition switch on disconnect the wires to the positive side of the coil and check the voltage going to the coil. Then check the battery voltage.<br />How do you know you have a resistor wire? have you measured the resistance? Assuming it has one because a diagram or manual says it does, doesn't mean it hasn't been removed.

 

[Capt.P]

Re: Why am I blowing condensors

I suspected the alternator but I brought it too a shop and they said their was nothing wrong with it . Would too much volts hurt the condensor I thought it would burn the points like the previous owner said.<br />When the points turned out to be fine i just assumed my volts were ok and the previous owner got the 2 mixed up.

 

[Capt.P]

Re: Why am I blowing condensors

What's a dva meter Don S?I have checked the resistsnce with a OHMS meter. I will try to check the volts tomorrow Don and use a different meter to make sure. I have checked it that way before and I think it was around 11 volts.Thanks

 

[crazyray]

Re: Why am I blowing condensors

I would be looking for like 7-9 volts at coil + terminal with points open and switch in on position,if more than this you will burn points and or condenser

 

[Buttanic]

Re: Why am I blowing condensors

Make sure it is wired right, the resistor wire gets power fron the run position on the ignition switch not the starter. The wire from the starter bypasses the resistor wire when the starter is cranking the engine to help starting. Make sure the bypass wire is not on a starter terminal that is hot at all times, only when the starter is cranking the engine. Mallory or auto parts store condenser should not matter but I recently had a problem with a new Mallory condenser and have heard of others also having problems. Mallory may have gotten a bad batch of them. I switched to an auto parts store condenser with on problems.

 

[Capt.P]

Re: Why am I blowing condensors

OK went down to the boat, engine off disconnected wires from + side of coil checked volts on purple/red resistor wire 12.1 volts (TOO MUCH)battery volts 12.1 so I would assume the resistor wire is gone right???So I tested the resistor wire according to my omc manual (Disconnect purple/red 20 guage wire from coil.Disconnect purple lead at back of alternator. Connect ohm meter between the two,meter low ohms scale should read 2.0+-0.5)and thats what I got 2.3 ohms WHAT'S UP!!!

 

[bruceb58]

Re: Why am I blowing condensors

You tested it wrong. With the resistive wire disconnected there is no current going through the wire so there will no voltage drop across the resistive wire. That is why you got full voltage.<br /><br /><br />I am going to repeat what Buttanic said here. There is another wire on + terminal on your coil right? This should be the one that comes from the starter solenoid. Just for a test, disconnect that wire, turn on your ignition and measure this wire's voltage. Should be zero. Crank your engine and you should get 12V. If it's already 12V when you aren't cranking, it's hooked up wrong.<br /><br />With that wire still disconnected, put back on your resistive wire and check your voltage. it should be 9 Volts.

 

[Capt.P]

Re: Why am I blowing condensors

Just wondering what do I do now?Should I just assume the resistor wire is gone?Should I cut out the resistor wire and put a coil with a internal resistor or can I buy a proper resistor wire to replace the old one?I tried wiring a ballast resistor inline but it still only dropped the volts to 11.8v.Thank You everyone for your help and patience.

 

[bruceb58]

Re: Why am I blowing condensors

Resistor wire sounds fine to me. It's the other wire that is probably the problem.

 

[Capt.P]

Re: Why am I blowing condensors

Thanks for the reply bruceb58 yes I realize the other wire goes to the solonoid and I did separate the 2 wires and test them their is no volts on the wire to the solonoid unless I am cranking

 

[bruceb58]

Re: Why am I blowing condensors

It's almost like your current through your coil isn't high enough but that doesn't make sense that your burning up points and condensors.<br /><br />Have you measured the resistance across the + and - terminals of the coil? You will need to do that with the wires on the + side disconnected. It should read very low like 0.5 ohms.

 

[bruceb58]

Re: Why am I blowing condensors

I may be totally off base here but maybe this is worth a try.<br /><br />On the negative side of your coil should be a wire that goes to your ESA and one to your tach. I wonder if it be worth trying taking these two wires off and repeating your voltage measurements.<br /><br />Another test you can do is to take the wires off the negative side of your coil and put a jumper wire from the negative side of the coil to the block. You should then measure the 9 volts at the positive side of the coil. You want to do this test fairly quickly.

 

[Capt.P]

Re: Why am I blowing condensors

Don s you suggested that Ihave too much power going to my coil and I do,but what should I do now?Put on a coil with a internal resistor?If so can I just use the resistor wire for power(since it has 12v anyway )or should I run another wire off the back of the alternator where the resistor gets it's power(purple wire)This problem just has me baffled.

 

[Cleopatra23]

Re: Why am I blowing condensors

Have you checked your high tension leads? If they are the ubiquitous carbon string type they may have become high resistance (especially the "king lead" the one to the centre of the distributor). If the coil has difficulty in "dumping" its stored energy into the spark plugs the extreme voltage produced will be reflected back across the points and condensor. (the coil is like a transformer) You don't really want anymore than 10,000 to 15,000 ohms in your HT circuit and whilst copper cored leads are the most reliable they can cause radio interference. Some plugs have built in resistors as do some plug connectors so watch out for multiple lots of resistance. As a last resort you could try a Voltage Dependent Resistor across the points. One with a breakdown voltage of about 250 volts should be about right. Farnell Electronics sell them. I am amazed that anyone can afford to run petrol engines anymore as in the UK we pay about £1 per litre (80% of this is tax!) Dunno what they spend it on. Good luck with your boat and best regards from Dave. (gone slightly Amish these days, i.e. NO ENGINES WITH TIMING BELTS, NO ENGINES WITH COMPUTER CONTROL or ECUs, and NO DRIVE BY WIRE. The old ways were best.)

 

[bruceb58]

Re: Why am I blowing condensors

I was looking back at your post where you measured your resistance wire. You sure it is 2 Ohms because that seems high to me. If your coil is drawing 4A, that would be 8V drop across the resistive wire. I always thought ballast resitors were closer to 1.5 ohm or lower. Maybe you have a 6V coil instead of a 9V!<br /><br />When you measure 12V at your coil's + terminal, are your points closed and engine not running or is the engine running at that time?<br /><br />Did you do the test that i mentioned before where you remove the leads from the negative side of the coil and run a jumper from the negative side of the coil to ground and then measure the voltage?