Ignition coil

[GaetanfromAnnecy]

Hello
I'm new on this gr??t forum. I'm french from Annecy in th? Alps. I have a 22 ft boat with an old but low millage 470 engine. I'm busy reworking the cooling system by changing all seals and cleaning exhaust manifold and elbow. I'm nos facing the issuse that the engine is not restarting. I'm should have An ignition issue and i'm suspecting the ignition coil. CAN d'ozone explain me if a 4,6V. Voltage at the coil contacts is normal ? Chat is the role or the resistive wireless from the choke to the coil ?
Thanks in advance.

 

[stonyloam]

Re: Ignition coil

Normal operating voltage for the 470 coil is about 7 or 8 volts. Your coil has two sources of voltage. When the starter is turning it gets a full 12 volts (battery voltage) from a wire (purple/yellow) attached to the slave solenoid on the side of the engine. That is because when the starter is turning the high current draw drops the battery voltage, and the direct connection assures enough voltage for the coil. When the key returns to run that connection opens and the coil gets its voltage from the purple resistance wire that runs from the electric choke to the coil + terminal. The resistance wire drops the voltage to the coil and that keeps the coil from overheating (drawing too much current). Check your battery voltage, should be 12-13 volts. Check the resistance of the purple resistance wire, should be 1.8-2 ohms. Clean all of your connections, and clean the contacts on your ignition points. A ignition file works best for the points. It is more likley the points than the coil.

This is how you can check your coil: Ignition off. Remove the cap and rotor. Open the points and slip an insulator (thin strip of plastic will do) between them. Pull the center wire out of the cap and place it so that it is about 1/4 inch (5mm) from metal on the block. Turn on the ignition, and take a short insulated wire (strip the ends) and use it to quickly make and brake a connection between the points. You should get a spark from the coil each time you remove the wire. If you get a nice strong spark your coil should be OK.

OH welcome

 

[GaetanfromAnnecy]

Re: Ignition coil

Terry,
Many thanks for your prompt reply but i'm just trying to understand why after removing and reinstalling for cleaning the exhaust elbow and manifold I cannot restart the engine!

In this operation, i have also removed the shift interrupter switch. This switch seeems to ground the pole ofnthe ignition coil through the white/green wire. Could you please explain me more on the role of this shift interrupter switch.
Sorry bothering with my problems ! Thanks in advance

 

[stonyloam]

Re: Ignition coil

Go to the "MUST HAVE Technical Information for DIYers" sticky at the top of the forum, and look at #4. Should tell you what you need to know. Good luck

 

[achris]

Re: Ignition coil

..... Could you please explain me more on the role of this shift interrupter switch....

Click-> How the Shift Interrupt system works.

 

[GaetanfromAnnecy]

Re: Ignition coil

All,
Many thanks for your replies. I found the solution of my problem into the MUST HAVE tech info. Engine was not starting because of a failed shift interrupter switch. I need know to start the next phase job on my engine : changing all water pump seals. The ebgibke is leaking coolan and i've noticed that it is leaking at the bottom of the water pump. I read some posts sayibg that this failure (leaking seals on water pump is typical of 470 engines)

 

[stonyloam]

Re: Ignition coil

Read this: http://www.sterndrives.com/470_coolant_leak.html You usually do not have to mess with the motor mounts, if you can get the puller on the alternator rotor. You also do not need any special tools to do the job. Come back with any questions that you have. Lots of guys here have done this job. It is not as bad as it sounds.