140 hp mercruiser starting issues, troubleshooting performed. Lost!

[biggjimm]

Try your timing light on all the wires & the coil wire or on your car or truck to verify that it is working. If it is working, but won't pick up off the #1 wire on the boat, then it's probably because the spark is in fact too weak.

Blast your plugs real good with some starting fluid or brake clean to clean them up & blow them out with compressed air to dry em good or let em set & air dry real good & they'll probably be ok to use when you get your new cap & stuff. Jim.

 

[Motodox]

Ok yeah I did just that when it wasn't working off the plug wire. I tried it on my truck just to make sure it worked and boom worked perfect. That makes me feel I'm really not getting enough spark through wires. Will see what the new parts do and I'll post back!

Stay tuned!!

 

[biggjimm]

Yeah that makes me feel like the tune up kit will have you up & running too. Good luck.

I sent you a pm, did you get it?

 

[flipbro]

Be sure to put a little dab of dielictrical grease on carbon electrode in center of new cap. Also blue loctite to hold rotor on distributor shaft.

 

[ibrw1]

Did you ever measure the voltage on the coil when the starter is running. The coil is 3 ohms, the resistor wire is 3 ohms, this voltage divider places 6 vdc on coil when normal running. When the starter is running/engaged the full battery voltage is sent to the coil from the starter. Using the timing light for this test may not work. Right or wrong, It's worth a check.

 

[Motodox]

ok guys parts came in this morning cap rotor and wires. put them on and still nothing!! doesn't even try to start.. still wont run my timing light of #1 plug wire.

I even pulled a plug and and tested for spark and it does have spark, but honestly it seems intermittent. Like it sparks well at first but almost dies off or doesn't spark consistently.

I have 8v at the coil with the key on. while still checkin voltage I crank it over and it drops to like 3.5v-4v and fluctuates as cranking. comes up to 5v and drops back down to 3.5v still while cranking. Does this mean anything.

Should I replace the coil next? it ohms out to 3ohms . my resistor wire should be good as well. I even by passed everything and put 12v directly to coil with a jumper and still nothing.

What do you guys think I should do now? so frustrating

 

[Rick Stephens]

Personally I have thought pickup or coil all along. I'm leaning pickup more than coil.

 

[jaa241]

How long have you been leaving the key turned on without the engine running? Longer than 30 seconds?

 

[flipbro]

Is the ground wire to the back of the distributor good? Its a long shot but very possible.

 

[Motodox]

How long have you been leaving the key turned on without the engine running? Longer than 30 seconds?

If your speaking of when it was running, I had the key on for long periods of time for listing to the music. I didn't think about the coil being energized while sitting there.

This bad?

 

[Motodox]

Personally I have thought pickup or coil all along. I'm leaning pickup more than coil.

I'm about to say screw it and buy new coil and pickup.
It's just weird I have spark and the pick up did test good using this test procedure below
http://s29.postimg.org/l22tg83l3/image.jpg

 

[Eric 3.7LX Alpha 1]

If your speaking of when it was running, I had the key on for long periods of time for listing to the music. I didn't think about the coil being energized while sitting there.

This bad?

Yes... it can cause damage.... (directly from Pertronix)

What will happen if I leave the ignition switch on when the engine is not running?

Leaving the ignition switch on when the engine is not running, can cause permanent damage to the ignition system, and related components. This does not apply to the accessory position of the ignition switch.
http://www.pertronix.com/support/tips/default.aspx#a3

 

[Silvertip]

Don't try to start the engine with new plugs until you replaced the cap, rotor and wires or you will foul those new plugs.

 

[jaa241]

With your boat being old I am assuming it doesn't not have an accessory keyturn. Your pertronix unit yes will still function occasion, but unit will start to malfunction and your coil will also overheat and lose ability to charge. Not saying your coil is bad, but a cold coil will work until it get hot and will not function or occasionally will until cool, hence why people say if they let there boat sit for 15 /20 minute they can restart boat and get to dock. As stated before theoretically it is a switch that opens and closes but it is a little more advanced than that. Even if you change coil, you will probably fry that coil within the year with pertronix 1. Best option in my option is order from amazon pertronix 2, they do make ccw and cw units. ( so order right one) if you see no change then return it to amazon.

 

[Motodox]

Looks like I'm going to order a pertronix II kit with a new module and new coil. This better fix it!?!? Lol

Do guys run your timing light of #1 spark wire and timing light works fine ?

Is there any problem with having different compressions like my #1 cylinder has 150 #2 has 135 #3 has 150 and #4 has 150. Is that not a problem? Of course engine is cold while checking the compression.

 

[Rick Stephens]

Your compression is darn near a brand new motor. Merc allow your lowest cylinder must be within 70% of your highest. You're within 90%.

www.boatfix.com/merc/Bullet/97/97_25.pdf

The new Pertronix is going to resolve this. And the new cap, rotor wires and plugs were necessary with the new ignition. Nothing wasted 'cept time.

RIck

 

[ibrw1]

I put new ignition switches in both of my boats, new switch has 4 positions, 15amp
Acc, off, run, start. The stereo and depth finder goes on acc. $20 bucks.

Just a thought

Good luck man!

 

[Motodox]

I just hooked my stereo to 12v constant because you can shut it fully off anyway. So no listing to the music all day with the key on!

I really hope this does the trick!

 

[biggjimm]

Beings the cap & wires didn't do it & you still have a weak, intermittent spark, plus with the problems outlined before with the petronix 1 unit, I too would go ahead & order the petronix 2 & new coil & you should be good to go. And like Rick said about the cap & wires, nothing wasted & I'm guessing they were old & in need of replacing anyhow. Look at all the knowledge you've gained & the great people you've met thru this problem. You'll be an ignition system wiz after this & you'll be answering other people's posts when their boat won't start. All good, except the frustration along the way.

I just put the head & new cam back on mine today. Put the manifold & carb on in the morning & the outdrive & going back to the lake. With positive results this time!

Good luck & will be waiting to hear how good that boat runs out. Jim

 

[biggjimm]

I just thought of something for you to check.

Does your boat have a tachometer at the helm? If it does, disconnect it. It hooks to the coil - terminal & depending on the year it might be grey or if it's older it could be dark brown like mine.

Those tachs, especially on an older boat, get all jacked up inside & ground out that circuit, essentially becoming a kill switch for your ignition. If I hook my tach up, the engine will start missing & surge for a few seconds & then die. Every time.