No spark, help!

[GoCanada72]

I have to admit I don’t own a Nautique, but I do own an ‘85 Ski Supreme with PCM 351 and I’m hoping someone here can help me out.

Went to fire the boat up for first time since Oct last year yesterday. Turned over strong but never fired, even with starter fluid. Not even a sputter.

Battery is good. Pulled spark plug, it was pretty black. Tried testing plug wire for spark with screwdriver against block, nothing.

Inspected distributor/points and all looked pretty clean. Borrowed neighbours timing light, and it flashed on coil wire, and plug wires.

I checked voltage at coil and it was 4.8 V with key on points closed.

I’m thinking i have weak spark and was going to head back to lake with one of those spark tester devices to see how strong the spark is (along with a new set of plugs).

Do you think fouled plugs could cause no spark/start issue? I figured you would get something going, but maybe just rough. What are the chances of them being all bad?

Any help would be appreciated!!!

Thanks!

[SilentSeven]

For the engine to start, you need three things - fuel, spark and correct timing. You'll need to work backwards to check each one. If the boat won't fire with starting fluid, it's likely timing or spark.

For spark, do a simple test with a screw driver from the plug wire to block. Put a screwdriver in a plug wire and hold it next to the block while someone cranks the engine. Look a a nice blue zot. If you don't get it, R&R your ignition system - new points with correct gap, condenser, cap and rotor. Replace the plugs with new one again with correct gap. If that still doesn't get you spark, consider replacing the coil. When was the last time your plug wires were changed? Poor wires won't prevent a start but will keep is from running well.

Has the distributor been moved (rotated) since it last ran? If so, the timing can be off. Are you sure the plug wire leads are on a the correct distributor locations? Common mistake is to remove all the plug wires when doing distributor work and then not replace correctly. Spark timing will be off and this will cause a no start.

Black plugs suggest a fuel metering problem with the carb. If you get spark and timing sorted, the boat should fire on starting fluid. You may still need to look at the carb after you get the boat running.

Good luck.

[bturner]

On a car with a stock point system cranking voltage at coil should be about 9 - 10 volts. 4.8 is low IMO. My first go to would be test with another KNOW GOOD, fully charged battery. A battery with a dead or weak cell can show 12 volts and fall on it's face under load. Unless you've load tested the battery don't assume it's good.

Don't know if they use a ballast resistor in a 95 boat but this would probably be the next place I would check. It's possible you have a bad coil but with only 4.8 volts showing up for the party I would be looking to fix that first.

As always this assumes you've checked the condition of all the cables, connections and grounds.

[GoCanada72]

Thanks all! Not sure if it matters, but just to be clear the 4.8 V at coil was just with key on, points closed, not cranking. I’m kind of new to this so I apologize if I’m explaining things wrong. Should I be testing some other way?

[GoCanada72]

The distributor has not moved since last ran. I tried boosting with car (running) hopefully that wasn’t a mistake. Because of that I ruled out battery.

[bturner]

Get the voltage while cranking. 4.8 still sounds low to me. My 70 Mach 1 runs at about 6 volts when in run and 12 when cranking. It has a resistive wire in the circuit which does this. GM and Mopar used a ballast resistor for this. Newer electronic ignitions run at 12 volts. At least this is my understanding but then again I haven't worked on a point based ignition in years. Back when I did I immediately and installed a Pertronix ignition (a lot easier to install than it sounds) to replace the points and the coil, both ran at 12 volts as best as I can remember.

https://pertronixbrands.com/pages/pertronix-ignition

TBO I have no idea what the voltage should be on a 95 PCM system but a place like Discount Inboard Marine would be able to tell you quickly if you pick up the phone and call them.

https://skidim.com/?SID=arfbktcs1ijpulb5sl01g5p2me

If you have a dead cell jumping will not rule out a bad battery, a load test would or the battery in the car replacing the one in the boat would.

[Jonny Quest]

1. Don’t use Starting Fluid. It’s very hard on the combustion chamber.
2: Check voltage before and after ballast resistor (this is just before the coil). Report back.
3. If you don’t know when plugs, wires, cap and rotor was last changed, you may want to consider changing all out. Relatively inexpensive.
4. Distributor maintenance. Points, condenser, advance mechanism cleaned and lubed.
5. Black fouled plugs can indicate oil burning (wet black) or too rich fuel mixture (black dry). Post pictures of plugs.
6. Set timing to PCM spec.

JQ

[GoCanada72]

I’m going to swap battery with one I know works, and install new plugs. Can someone explain how to connect multimeter to test coil voltage when starting? I’m kinda new to this .

[Skidave]

Upgrade your ignition to an electronic style and ditch the points. Do new coil, wires and plugs. The kit comes with a good amount of stuff, the rest is maintenance items.

Call Discount Inboard Marine. They have the parts and support you need.

Sent from my SM-J337V using Tapatalk

[GoCanada72]

I’m looking into that, but for for right now, does that breaker look ok to you? I just noticed it while going through some photos . Boats 1.5 hrs away so I can’t really check it right now.

[Skidave]

My opinion on that breaker...shoddy fix. That is not the correct style of breaker and who knows if it is the correct rating.

Did you measure your resistor and make sure it is the proper resistance? I forget the rating since I sold my old boat so long ago. But measure it with an ohm meter.

I do know electronic conversion kit has you bypass the resistor.

Sent from my SM-J337V using Tapatalk

[GoCanada72]

I tested for spark with a light that plugs inline. It lit up, but very faint. I also tested the strength of the spark with another tester, but I couldn’t see any spark at all even when set very close. I was starting to doubt if it had spark. I installed new plugs, then gave if another try, and I could hear it fire a couple of times. With a bit of help from some starter spray, and some coaxing, it started! Thanks to all for your help! Here is a picture of the the old plugs.