Purple wire to coil voltage

[sgajan]

ok here i go with an issue.
its a 1990's 3.0 omc engine with est distributor.
Symptoms im having :
Bogging and popping from the carb.
the voltage meter on the dash jumps all over the place from around 12v to 14v
tachometer guage goes up to like 4500 when boat is barely moving. (eliminated tach to rule it out)


Heres what ive done to try and correct it:
((plugs wires cap and rotor just bought and installed to try and eliminate the problem so thats not it))
eleminated the shift assist wires (no difference)
disconnected the tachommeter wires (no difference)
looked around for any other wires that are lose. (no difference)
11.61 volts to the purple wire with ignition key on position.
8 volts to the purple wire when engine is running.

NOW FOR THE FUN PART !! I applied voltage to the purple wire on the coil straight from the battery. Took the boat out for about 20min (Boat runs awesome) WTF? Also with the wire conected to the battery the voltage meter on the dash is normal and not jumping all over.

Bad part is the engine wont shut off with the key due to being connected to the battery.
Both batteries are new and it happens on either battery.

Any ideas why 12v straight to the coil will all the time will make it run good?
Something on alternator cause this maybe?

 

[stonyloam]

Re: Purple wire to coil voltage

The purple wire(s) supply 12V to everything from the ignition "on". Get under the dash and clean and tighten ALL of the purple wire connections, including the pins on the plug. Just sounds like you have some corrosion or loose wire somewhere between the switch and the coil. To eliminate the switch as he problem, apply 12V directly to the purple wire at the back of the switch. Good luck.

 

[Don S]

Re: Purple wire to coil voltage

Any ideas why 12v straight to the coil will all the time will make it run good?

When you put power directly to the coil, you bypass all the wiring from the engine to the helm and back again. That's a lot of connections. Including the main harness plug on the engine, kill switch, ignition switch, every wire connection on the instruments, and the same purple wire powering the ignition also powers the instruments.

 

[sgajan]

Re: Purple wire to coil voltage

if i may add a new detail to the mix.
When testing for the 12v at the purple wire. IF and only IF I disconnect the pink and brown wired plug from the distibutor THEN I get the full 12v to the ignition coil. With the distributor plug connected I get 11.6v to purple.

 

[stonyloam]

Re: Purple wire to coil voltage

if i may add a new detail to the mix.
When testing for the 12v at the purple wire. IF and only IF I disconnect the pink and brown wired plug from the distibutor THEN I get the full 12v to the ignition coil. With the distributor plug connected I get 11.6v to purple.

Not very familiar with the est, but since you run OK with 12V directly to the coil, it is logical to conclude that you are NOT getting 12V from the ignition switch, so that is where you need to look. Try removing the purple wire from the coil, and running a jumper directly from the ignition switch purple wire terminal to the coil. See if she runs OK then. If it does, then your trouble is somewhere in between.

 

[sgajan]

Re: Purple wire to coil voltage

Thanks for the ideas.. i will try the new 12v wire from the switch tomarrow. Has anyone heard of the voltage dropping when plugging in the dizzy connector? Almost sounding like something in the distributor is contributing to this BUT :/ dunno cus i cant run the darn thing with dizzy wires disconnected and thats when i get the large voltage drop down to around 8 or 9v

 

[matey487]

Re: Purple wire to coil voltage

just my 2 cents, but i had problems like that as well. the fix was to replace the caps that go to the fuses in the dash, the main fuse cap was intermitant , good part cheap repair, bad part hard lesson learned

 

[sgajan]

Re: Purple wire to coil voltage

WOW that sux Im gonna check those fuse caps tomarrow also..thanks

 

[sgajan]

Re: Purple wire to coil voltage

Fuse caps look fine.
Update though,
I ran the wire from the ignition switch to the coil. I get 13.5v when key is on and 13.5 when running. I took the boat out for a ride and HOLY CRAP the thing has never ran so good. I always used to smell fuel from the exhuast when idling and running. Possibly it was from weak spark and this issue cus i dont smell that anymore But anyways I still havent traced down why it does the 9.5v on the purple wire wen runnin. Its definately after the engine harness connectors considerin it runs fine bypassing the consol guages. But where? sort of glads this happened cus i found that one of my bolts on my starter unscrewed ..fixed tho :/

Thanks for the help so far.