Ignition Module Is Bad on Thunderbolt V?

[milkyway]

Mercruiser 5.0 v-8 with thunderbolt V ignition.<br /><br />The red/white wire coming out of the ignition module reads only 10.25 volts instead of 12. Manual however does not state it has to be perfect 12. Battery is fully charged and reading close to 13 volts. Is the ignition still good? Can it be the reason I am having hard starting? It starts all the time but needs 3 or 4 attempts on the ignition switch.

 

[milkyway]

Re: Ignition Module Is Bad on Thunderbolt V?

Correction - I am asking if the "Ignition Module", which costs close to $400, is good, still usable, or must be replaced.

 

[Don S]

Re: Ignition Module Is Bad on Thunderbolt V?

What year ya got there, and what manual are you using?

 

[milkyway]

Re: Ignition Module Is Bad on Thunderbolt V?

It's 1999, and it's seloc manual. Not the factory manual, but I still find it useful in many respects.

 

[Don S]

Re: Ignition Module Is Bad on Thunderbolt V?

I wouldn't order a module yet, since you did have some voltage, I would check for some corroded terminals on the wiring going into the knock sensor and module.

 

[milkyway]

Re: Ignition Module Is Bad on Thunderbolt V?

Ok. I will keep using it. Will check "all" connections and apply fresh dielectric. Tommorrow I will also test the ignition coil. Thanks. <br /><br />I have logged 200 hours and still have not changed the plug wires, distributor cap, and all those inside the cap. Just the plugs after 100 hours. Engine still runs great and cruises 18 to 20 knots at only 3000 rpm. When new to boating, I always hit at least 4000 rpm, but I wondered what's the rush. And I was only making the engine work harder. I still have not learned how to use a timing light, set dwell, not even how to crank the engine without using the ignition switch. I will work on this whole tune up process just before I make my last launch.

 

[Don S]

Re: Ignition Module Is Bad on Thunderbolt V?

Originally posted by milkyway:<br /> Ok. I will keep using it. Will check "all" connections and apply fresh dielectric. Tommorrow I will also test the ignition coil. Thanks. <br /><br />I have logged 200 hours and still have not changed the plug wires, distributor cap, and all those inside the cap. Just the plugs after 100 hours. Engine still runs great and cruises 18 to 20 knots at only 3000 rpm. When new to boating, I always hit at least 4000 rpm, but I wondered what's the rush. And I was only making the engine work harder. I still have not learned how to use a timing light, set dwell, not even how to crank the engine without using the ignition switch. I will work on this whole tune up process just before I make my last launch.

Ok, mind telling me what your problem is? What's the deal with the 10.25V if everything is running fine.<br />Other than bragging how long you can go without a tuneup and making your boat run at it's best, what have you gained? It sure wasn't fuel milage.

 

[Dunaruna]

Re: Ignition Module Is Bad on Thunderbolt V?

Milkyway, dwell is not an issue if you have an ignition module, it's self adjusting.

 

[milkyway]

Re: Ignition Module Is Bad on Thunderbolt V?

No dwell? Self addjusting? Good. How about timing? <br /><br />So more or less all I have to do is replace parts.<br /><br />The original problem is I have to turn the switch at least 4 times before it starts. It used to be "1 click". So I am trying to find the potential cause, other than tuneup.

 

[prockvoan]

Re: Ignition Module Is Bad on Thunderbolt V?

Check or change out the fuel filter,tune up is a must.Take Don S word as best.Don't Tee him off,he is a walking book,one of the best for trouble shooting when not even able to see or hear the problems of an engine.

 

[tommays]

Re: Ignition Module Is Bad on Thunderbolt V?

http://www.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=24;t=012808 <br /><br />if your clicking as in the motor does not turn over you have something covered in this don's post<br /><br /><br />tommays

 

[milkyway]

Re: Ignition Module Is Bad on Thunderbolt V?

No dwell? Self addjusting? Good. How about timing? <br /><br />So more or less all I have to do is replace parts.<br /><br />The original problem is I have to turn the switch at least 4 times before it starts. It used to be "1 click". So I am trying to find the potential cause, other than tuneup.

 

[rodbolt]

Re: Ignition Module Is Bad on Thunderbolt V?

when making the start attempt does it just click or does it crank over and not start ?

 

[milkyway]

Re: Ignition Module Is Bad on Thunderbolt V?

It cranks the regular way but just won't start right away.<br /><br />In removing the the distributor, the manual says to "rotate the crankshaft until the #1 cylinder is in the firing position". How do you rotate the crankshaft? Is this the engine itself that has to be turned?<br /><br />And on the manual's pictures, the distributor cap has 2 of #1's (i have v-8). Why is that? <br /><br />And which one of the 2 is the #1 cylinder that has to be in the firing position?<br /><br />These questions are basic for you guys, but I have not seen the inside of a distributor so I am going easy on this one before I start dismantling anything.

 

[prockvoan]

Re: Ignition Module Is Bad on Thunderbolt V?

You can rotate the engine by bumping it over with the starter or with a scoket wrench on the crankshaft pully.Note*If you use the later,rotate the engine only the way it runs,NEVER back it up.<br />As for as the distributor cap,if you are showing numbers double(one on top of the other),use the one closest to the studs.The other numbers are for a reverse rotating engine.Number 1 cyl is #1 cyl for cw or ccw rotation engines.

 

[milkyway]

Re: Ignition Module Is Bad on Thunderbolt V?

I prefer the socket wrench on the pulley. Now I have hit the ignition switch to see what direction the belt turns. Thanks.

 

[Bondo]

Re: Ignition Module Is Bad on Thunderbolt V?

Originally posted by milkyway:<br /> I prefer the socket wrench on the pulley. Now I have hit the ignition switch to see what direction the belt turns. Thanks.

SBCs turn CW looking at it from the Front of the motor,............<br /><br />If you're going to turn the motor with a Wrench,.....<br />I recommend that you remove All the Sparkplugs 1st,.........<br />Otherwise,..... It's possible to Strip the threads out of the Crankshaft when coming up against Compression..............<br />

It cranks the regular way but just won't start right away.

It's a Carbed motor,.. Right,..???<br />Do you Pump the throttle,+ Set the Choke,..???<br /><br />Other than it's Probably time for a Tune-Up,........<br />I Don't think this is your Starting Issue...........

 

[milkyway]

Re: Ignition Module Is Bad on Thunderbolt V?

It's carbed. NO I don't pump the throttle. I just click.<br /><br />I opened the distributor cap and noted corrosion forming on the sensor assembly. This part I know has to be replaced when the tune up is to be done.

 

[Don S]

Re: Ignition Module Is Bad on Thunderbolt V?

It's carbed. NO I don't pump the throttle. I just click.

No wonder you have problems getting it started. A carbed engine does not start like an EFI engine.<br />You need to pump it at least once to set the choke and squirts some gas into the intake so it will start. Hopefully the choke is set right, then you may have to baby the throttle and keep it up around 1000 rpm till it will idle.

 

[milkyway]

Re: Ignition Module Is Bad on Thunderbolt V?

Ok, you are the Captain. The marina instructor said there was no need to prime. Only after long storage.\<br /><br />There is a new thread about starting a carrbed engine. He is addressing how to properly start a carbed engine. It's on active post. Can you please address his question., The only follow up matter I hgave on his comment is: do you need to switch in the ignition when priming because the fuel pump is electric?<br /><br />Thanks for your patience.