proper testing of a internally resisted coil?

[ussoldier_1984]

What should the proper ohms be between the positive lead and where the coil spark wire goes on the coil and same for the neg to spark coil wire. coil part number is 805570A 2. want to make sure coil needs to be replaced before I go pick one up. I have done all the troubleshooting on the flow chart for testing thunderbolt IV ignition systems Im at the point where I need to swap coils to see if i get spark if I get spark im good if not replace ignition sensor thing.

95 maxum 1800sr mercruiser 4.3 lx thunderbolt IV ignition

 

[Alpheus]

Re: proper testing of a internally resisted coil?

Primary resistance = .60-.80 Ohms.

Secondary resistance = 9.4K-11.7K Ohms.

 

[ussoldier_1984]

Re: proper testing of a internally resisted coil?

primary is the positive on the coil and the secondary is the neg side correct? just want to make sure. Also alpheus i was reading another ignition problem on a 94 thunderbolt 4.3 forum here and someone was saying to test the ignition module put the positive lead of multimeter on the neg of coil and neg to a ground take the green white wire and tap it against a ground voltage should drop from 12 to 7-8 then jump back to 12 is that correct testing of the ignition module? if so I tried it and my voltage stayed at 12 volts does this mean I need a 300 dollar ignition module?

 

[Aloysius]

Re: proper testing of a internally resisted coil?

Secondary voltage is HIGH voltage. The negative terminal grounds at the distributor, so primary resistance is between positive and negative terminals. secondary is between the tower and ground.

The coil is just a transformer.

 

[Alpheus]

Re: proper testing of a internally resisted coil?

 

[ussoldier_1984]

Re: proper testing of a internally resisted coil?

Do i have to have the coil hooked up to test the secondary? cause I thought you had to disconnect it to test lol on my primary according to your steps I got .7 ohms secondary i did between the tower and the neg terminal on the coil and I got zip nothing no reading at all just O.L

 

[Alpheus]

Re: proper testing of a internally resisted coil?

http://autorepair.about.com/od/troubleshooting/ss/coil-test-ohm.htm

 

[ussoldier_1984]

Re: proper testing of a internally resisted coil?

coil was good turns out it was a bad ground coming off the ignition sensor in the dist relocated the ground and was good for a while. then boat started doing its crazy thing timing starting going nuts. when the engine reaches full temp including the heat transfer through the dist shaft to the ignition module, it is making my ignition module go nuts throwing timing all sorts of crazyness soo i need to buy a new module only 300 bucks so to all those people say that it either works or dosen't I call bull crap on you. Mine is proof that they can act up before they fail completely. I'm tired of the thunderbolt bull crap im switching the entire ignition to a chevy hei dist with mechanical advance. I can get everything I need on ebay for 100 bucks and no more worries about computer hall sensors and other crap going wrong.

 

[Alpheus]

Re: proper testing of a internally resisted coil?

chevy hei dist with mechanical advance

Its a Marine distributer correct? You will also have to rig up the shift interrupt circuit as well...

 

[ussoldier_1984]

Re: proper testing of a internally resisted coil?

it sure will be and I already have the plans written up on the shift inturrupt switch thanks

 

[Aloysius]

Re: proper testing of a internally resisted coil?

I've never seen a marine HEI.

 

[boat127]

Re: proper testing of a internally resisted coil?

first remove your distributor cap and havea look at the ignition sensor under the rotor. if its rusty and corrored replace it. symptoms of it failing at backfiring out the carb then dies when it is warm then not having any spark. they are about 40 bucks. if your module is mounted to the carb remove it and coat the mounting surface with dieelectri grease and put it back on

do not use an automotive distributor in your boat its a fire and explosion hazard and if it kills your family or someone else your insurance will not pay you.

 

[ussoldier_1984]

Re: proper testing of a internally resisted coil?

the actual distributor is the same the only difference is the dist cap. so probably just going to get a standard chevy hei dist (got this info off of this website http://forums.iboats.com/showthread.php?t=38985

 

[ussoldier_1984]

Re: proper testing of a internally resisted coil?

first remove your distributor cap and havea look at the ignition sensor under the rotor. if its rusty and corrored replace it. symptoms of it failing at backfiring out the carb then dies when it is warm then not having any spark. they are about 40 bucks. if your module is mounted to the carb remove it and coat the mounting surface with dieelectri grease and put it back on

do not use an automotive distributor in your boat its a fire and explosion hazard and if it kills your family or someone else your insurance will not pay you.

New dist cap new rotor button new ignition sensor new wires new plugs new coil all this past month. even if the ignition sensor is bad again im sick of thunderbolt IV its garbage!!!!

 

[Aloysius]

Re: proper testing of a internally resisted coil?

If it doesn't have "marine" certification it isn't marine. Period. May be the "same", but not for insurance purposes. Practically you'll be fine, UNLESS there are gas fumes..................

 

[ussoldier_1984]

Re: proper testing of a internally resisted coil?

ahhh found it msd makes a marine ignition system for the same price I can get a silly ignition module

 

[dubs283]

Re: proper testing of a internally resisted coil?

I've never seen a marine HEI.

more commonly known as EST electronic ignition - found on most all newer mercruiser 3.0 L engines, 7.4/454/502 Mag MPI engines, and some SBC chevy mercruiser engines

my question is why the OP is deciding to change over to this?? Yeah, its a decent ignition system, but if you can't figure out the quite simple t-bolt ignition, what makes you think the HEI ignition is going to be better/easier to work with??

and $100 for an entire ignition system?? used?? sure, but you are getting just that, used parts that may or may not work, plus the time and trouble to install and setup properly - and new cap, rotor, wires, plugs - now you're getting close to the $300 range for a new t-bolt module

plus all the new parts you've already sunk into the t-bolt ignition??

 

[ussoldier_1984]

Re: proper testing of a internally resisted coil?

well if you want to buy me a new ignition module for 300 bucks ill be more then happy to take it haha j/k but seriously i can get an hei distributer and then a marine dist cap that has the only thing that makes it marine grade the vent tube for about 130 bucks and it simplifies my ignition system and is more reliable. Its not that I dont understand the thunderbolt IV I completly understand this ignition system inside and out. Im just tired of the same things going wrong with it started out with a bad coil and spread like a disease to the ignition module.