87 OMC electric

[Bigdaveaz]

Is there a "step down " resistor on the ign? I am reading 4 volts at coil+ no start, ran a jumper to Batt START! where is this resistor located? Dave

 

[Boatin Bob]

Re: 87 OMC electric

It's actually a resitor wire built into the wiring harness. Find the purple/black wire on the positive post of your coil, it goes back to a splice into a wire from the alternator.

 

[Bigdaveaz]

Re: 87 OMC electric

Thank you Bob. One more question,(do they ever stop) I have engine running on the ear muffs and much water out at front of drive where lower meets upper,is this normal?

 

[rock_doctor]

Re: 87 OMC electric

Unhook your tach wire (gray wire) and retest voltage. If that does not fix it then get a coil with an internal resistor and run a new wire from your ignition switch to the coil. Been there done that.... I would also convert the points to an electronic system. Not too hard to do, replace the points with the hall effect sensor and wire two resistors to the electronic shift module. Just make sure you solder the resistors. Took me about 20 mins and was well worth the trouble.

Any amount of water out of the upper part of the drive is fine. The exhaust bellows are split along the top to reduce back pressure and the water is coming out of this area. If you are not seeing any water out of the prop then your exhaust bellows may be broken. If you are not seeing any water out of the upper drive and it is all coming out the prop that is also ok as long as it is a nice flow.

 

[Bigdaveaz]

Re: 87 OMC electric

Rock Doc,thank you,I plan on replacing the old points/coil. I do get water out of the prop hub! Was at the Boat shop today, they also said water above is ok. Had a strange thing on ign. in the am,crank no start,checked voltage to the coil,4.7v. ran a jumper from batt. to coil,started fine,removed jumper turned on ign. and read 12v at coil?

 

[rock_doctor]

Re: 87 OMC electric

I would pull the wires to the coil apart and clean the connections. Getting the proper volt to the coil after jumping it tells me that either the points were closed when you checked it the first time or something is dirty. I had the same exact problem with my 86 and i just got a internal resistor coil and ran a fresh line from the run side of the ignition switch. Once you change the coil and find it wants to cut out at speed or is funky on the water, try unhooking the tach. When they short internally it will keep the coil from pulsing. You should not be reading 12v at the coil unless the starter is turning. You have two power connections to the coil. One from the starter which supplies 12 v when cranking and then the resistor wire from the alt that supplies power when running. If you are seeing 12v w/o the starter turning then something is not right. It is a simple system just work your way through.

good luck

 

[bruceb58]

Re: 87 OMC electric

Had a strange thing on ign. in the am,crank no start,checked voltage to the coil,4.7v. ran a jumper from batt. to coil,started fine,removed jumper turned on ign. and read 12v at coil?

If you are seeing 12v w/o the starter turning then something is not right.

When you read the lower voltage, your points are closed. When you read the higher voltage, your points were open. Since no current goes through the coil with the points open, you don't have current running through your resistor wire and that is why you don't get the voltage drop across it.

 

[Bigdaveaz]

Re: 87 OMC electric

Makes a lot of sense! I will go thru the system. Now for a new problem, Why do I get diminished water flow from the impeller to the t-stat housing, no flow under 2k, none at idle! Back flushed system and installed a new impeller, runs at temp with earmuffs. Had it in the tank today, Dave.

 

[Bigdaveaz]

Re: 87 OMC electric

When you read the lower voltage, your points are closed. When you read the higher voltage, your points were open. Since no current goes through the coil with the points open, you don't have current running through your resistor wire and that is why you don't get the voltage drop across it.

What should voltage read on the +side of the coil with ign/start?

 

[bruceb58]

Re: 87 OMC electric

What should voltage read on the +side of the coil with ign/start?

While you are cranking, you should be measuring the battery voltage. this may be less than 12V depending on the drop due to the starter current.

 

[Bigdaveaz]

Re: 87 OMC electric

Gotcha, two circuits to coil,one from Starter and one from alt. thru resistor ? Starter volts minus starter motor pull, what is resistor voltage?