First splash '13-good news, bad news

[John C in PA]

Good news: the prop work done to my SST by DAH Props gave me about 0.7 MPH (for a best ever 59.3 MPH GPS). The Garmin doesn't look too ugly set dead center of the wheel and is EZ to read with the polaroids. The industrial strength velcro held fine. Powering it up with a lighter plug seems to work fine too.

Bad news: after blasting around for an hour I idled a bit to play with the GPS. Then the motor just stopped. I have fresh fuel and the acellerator pump injects gas nicely. It seems like no spark. The MSD High Vibration coil I added last year felt a bit hot but when I replaced it still no start. All guages move when powered up. New MSD 8.8 wires this year. All plug wires are tight on each end. Coil wire is fine. Distributor is electronic. Usually the motor starts as soon as I hit the switch. Ideas? What to try?

John C

[duckhunter]

Ok, off the top of my head in order of likelihood:

- Engine circuit breaker - some of them are hidden.
- Bad ign module.
- Bad or weak coil.
- Short in the ign wiring somewhere.
- Some sort of neutral safety switch or safety lanyard issue. The motor shouldn't crank if either of these were the culprit, but who knows with electrical gremlins.

Tough to troubleshoot these things sometimes. Did you get it restarted? Is there any spark at the plugs? You aren't still floating around the lake waiting for an answer are you?

[John C in PA]

Ok, off the top of my head in order of likelihood:

- Engine circuit breaker - some of them are hidden.
- Bad ign module.
- Bad or weak coil.
- Short in the ign wiring somewhere.
- Some sort of neutral safety switch or safety lanyard issue. The motor shouldn't crank if either of these were the culprit, but who knows with electrical gremlins.

Tough to troubleshoot these things sometimes. Did you get it restarted? Is there any spark at the plugs? You aren't still floating around the lake waiting for an answer are you?

• Only 2 large CB's I know of are on the STB side at the front of the motor by the electrical plug in. Both were not tripped.
• Bad Ign module: possible. Not sure how to check.
• old coil re-installed. Still no indications of ignition.
• short in the wiring. ****!!!
• neutral SS: maybe
• safety lanyard and main fuse in dash. I'll have to electrical test tomorrow.
• I wonder if the Weapons Fire Starter failed?

Thx Tommie.

[duckhunter]

Honestly I would guess your ign module overheated somehow or you have a short somewhere in the system. The CBs were just low hanging fruit to check... Maybe check your fuses too before you pull any (more) hair out, and double check your new ign switch and ensure that you didn't lose a wire end out of a cobble connector somewhere.

I would certainly pull a plug or two and see if you're getting a nice fat spark. How healthy is the charging system and battery?

Good luck, and good news on the prop and the GPS anyway!

[mattyboy]

John,

usually the last point of entry into an electrically circuit is the best place to start when troubleshooting, that being the switch you just installed. DH has hit on several good points it is now a process of elimination.

these are quick tests assuming what you have is the motor cranks/turns over but will not start/run

most nuetral safety switches break the lead going to the starter solenoid so if it is not in nuetral or the switch is bad no cranking. try to turn it over in fwd then in nuetral

The safety lanyard breaks or grounds the lead going to the ign coil if the lanyard is active or bad it would kill the juice to the coil but the motor would still crank.

test the switch, do the other accessories work when the switch is in the on position? voltage at the coil? What was the electrical rating for the new switch? the gauge bounce means the switch is sending voltage to the gauges at least.

usually there is a wad of wires on the key switch "on" lug maybe one loose or as DH said slipped out of the ring terminal crimp.

If there is no voltage at the coil I would eliminate the new switch and temp. wire the old key switch and test.

does the coil have an internal resistor or external?

[SanDogDewey]

Good news: the prop work done to my SST by DAH Props gave me about 0.7 MPH (for a best ever 59.3 MPH GPS). The Garmin doesn't look too ugly set dead center of the wheel and is EZ to read with the polaroids. The industrial strength velcro held fine. Powering it up with a lighter plug seems to work fine too.

Bad news: after blasting around for an hour I idled a bit to play with the GPS. Then the motor just stopped. I have fresh fuel and the acellerator pump injects gas nicely. It seems like no spark. The MSD High Vibration coil I added last year felt a bit hot but when I replaced it still no start. All guages move when powered up. New MSD 8.8 wires this year. All plug wires are tight on each end. Coil wire is fine. Distributor is electronic. Usually the motor starts as soon as I hit the switch. Ideas? What to try?

John C

Does the coil have a ballast resistor?

[mattyboy]

was thinking about it not really sure how much electronic stuff OMC used on their Fords. I think they have a shift interuptor as well , another point that kills spark.

[John C in PA]

Lotsa of stuff to try tomorrow.

DH: your suggestion is on my list although I'll check electrical first.

Mattyboy: the new start circuit will be first to check. The motor cranks fine but there is absolutely no attempt at firing. I'll be checking everything behind the dash (and what a crappy job Donzi did for my build). I've tried to start by placing the controls in various F & R positions. No fire. Kill switvch still has to be checked. The original coil said it uses a resistor but it may be internal (what does it look like?). MSD said I don't need one with electronic ignition. This motor usually starts almost as soon as the starter is touched. One thing I remembered is the motor seemed to sputter a little before shutting down. The shift interrupter (new last year) only kills every other cylinder doesn't it? I get no evidence it even tries to start.

John C

[pipnit]

Is your coil mounted horizontally by any chance?

[mattyboy]

John

if you are saying the motor turns over with the shifter in gear then you can eliminate the NSS it is most likely disconnected or you don't have one. Not really sure how it could be wired in to the ign circuit?? it is only activated when in neutral so if it was wired into the ign coil you would only run when in neutral.

the coil either needs an external resistor or has one internally, this will be marked on the coil. If it needs an external resistor there will be two wires on the + side one comes from the resistor and one from the key switch start circuit. the coil runs on 9 volts from the resistor but for hot spark to start it gets a full 12 volts from the key switch in the start position. If a coil that needs an external resistor keeps getting 12 volts when running it will get warm and will eventually burn out. The resistor I had looked like something from frankenstein a big ceramic block with brass lug nuts on each end. I guess in the day this setup was also to save the points and condensor from burning up too. I switched my coil to one that had the resistor built in.

From what I know about a shift interrupter is it momentarily kills the spark going into the ign circuit to stall the motor for a split second when shifting into gear. if it was held beyond momentary the motor would not run, not just ever other cyl. btw my 5.0 will run on 4 cyl don't ask how I know that.

[duckhunter]

John

From what I know about a shift interrupter is it momentarily kills the spark going into the ign circuit to stall the motor for a split second when shifting into gear. if it was held beyond momentary the motor would not run, not just ever other cyl. btw my 5.0 will run on 4 cyl don't ask how I know that.

Shift interrupter could definitely do it if it were sticking or shorting somehow.

Since you said this happened after a some running and idling I still think the module (if you have one) could have overheated or just up and died. That causes all kinds of flaky issues, from not running while hot to not running at all. Older Fords were notorious for this, I used to keep a couple of modules and a special ratchet for them under the seat of the tow truck. That and a ball peen hammer for whacking carbs with stuck needles - called it the Ford wrench. I just don't know if OMC used the same style module when they marinized the engine.

The new ignition switch should definitely get some scrutiny as well - as Matty pointed out, that was the last link in the ign circuit that was modified and could definitely be the culprit. The kill switch has stumped a lot of folks as well, myself included.

This stuff is frustrating, and it usually turns out to be something simple. Unfortunately it often takes a lot of troubleshooting to find the culprit.

[John C in PA]

Original and MSD coil horizontal. But that was OEM setup. 2 wires on + side of coil. no start in gear. New interrupter last year but will check. After starter. How do I check ign module?

[John C in PA]

Original and MSD coil horizontal. But that was OEM setup. 2 wires on + side of coil. no start in gear. New interrupter last year but will check. After starter. How do I check ign module?

[mattyboy]

John not sure if you have one but maybe can borrow from a mech. you may know. I used a hot wire switch when I re-did my motor which bypasses the wiring harness and takes the place of the key switch. it connects to the battery the starter solenoid and the coil the one I used had two rocker switches "ON" the other was a spring loaded "start" that would give you an idea if it is the wiring in the dash/switch or if it is engine related. I spent a ton of time on mine getting it running before I decided to yank and rewired it. I don't think you are at that point just check all of your connections especially the one that you have touched good luck

[John C in PA]

I get zero volts between ign switch battery terminal and distributor terminal when in run. Shouldn't I see 12 v?