Can't Get A Spark '86 3.0 120HP

[BillysBoat1986]

Hi Everyone! New to forums here. I have an '86 Thompson Bowrider 16 footer with the 3.0 liter' 120 HP inline 4 banger and Alpha 1 drive. I had the engine out to replace the engine to drive coupler. Now everything is back together. I couldn't get any spark so I installed a Flamethrower coil, Pertronix electronic ignition, new distributor cap and rotor, plugs and wires. Now I still I can't get it to spark while cranking. I removed the ballast wire and have 12V going to the coil from the main purple wire coming from the main harness (I checked with a meter also). When I hook up the spark tester to the coil output I only get a brief flash when I let off on the starter. Sometimes the engine does a slight jump like it wants to start while I release the start switch. But while it is cranking there is no light at all. I also tried hooking the coil straight to the battery and nothing. Also to note when I first replaced the distributor cap and rotor. The old rotor was stuck on and when I finally got it off the shaft was raised. I installed the magnetic sleeve and new rotor and the shaft was still to high. When I cranked the rotor struck the top of the cap and broke. I was able to get the shaft to lower and I have since replaced those parts. Could I have broken something else? It just doesn't make sense to me.

 

[stonyloam]

If you only get a single spark when you stop cranking, that tells me that your points or in this case your Petronix is not opening and closing. Your coil fires when the points open and the current through the coil stops, so when you stop cranking it will fire once as the current to the coil stops. Your problem may be the magnetic pickup of the Petronix not positioned correctly. You could try putting the points back in and giving it a try.

 

[BillysBoat1986]

I suspect the condenser on my old points is bad. I wasn't getting fire from them hence why I bought the pertronix. I set the .030 gap as per the instructions. Maybe I got a defective igniter. If I got a new condenser and points will that new flame thrower coil mess them up?

 

[stonyloam]

Should be fine, as a matter of fact I ran my Flamethrower II on points for a couple of years (back in my nonothing days) till I got my Petronix figured out, that I needed 12v to module. I believe the flamethrower coil will draw a higher current and tend to shorten the life of a set of points, but they should still last a couple of years. The purpose of the condenser BTW is to absorb the feedback spike from the coil primary windings and reduce arching of the points, which extends there life.

 

[BillysBoat1986]

Hmmm... Maybe if I just clean those points then. Real bummer the pertronix isn't working.

 

[stonyloam]

Use an ignition points file (any auto parts store) or a thin flat file to clean up the points. Sandpaper or emery cloth tends to round off the surfaces and leave grit behind that can cause poor contact.

 

[BillysBoat1986]

Ok... Cleaned the points and set the point gap to .020. Sparks like a champ now. Still haven't gotten it to start yet. It stumbles now. It's trying to fire up. Think I need to adjust the idle on the carb and adjust the choke now. Thanks for the help!!

 

[achris]

What about the timing? Messing with the points changes the timing, so at least check that before touching the carb, which I assume was work fine before the spark problem.

 

[BillysBoat1986]

I actually just rebuilt this carb. in April. I had the transom, drive out and redid everything new gimble bearing, bellows etc... So every step on this has been baby steps! Learning experience!

 

[BillysBoat1986]

... If I set the point gap in accordance to what they say in the manual... Will the timing still have to be adjusted after filing the points?

 

[stonyloam]

Yes. When you set the gap it could change the point on the distributor cam where the points open, and they will affect the timing, so you want to check it. You really should get ahold of a dwell meter and set the dwell, then recheck the timing.

 

[BillysBoat1986]

Thanks! I will check that now.

 

[thumpar]

Just for reference a 3.0l would be a 135hp or 140hp. If it is a 120 it is a 2.5l. I put a pertronix in my 2.5l with a flamethrower coil and loved the setup.

 

[stonyloam]

Ya know, this reminds me of when I did mine years age (470 but the same distributor), when I put the magnet over the distributor cam it sat too high and I thought it was not fully seated, so took a socket and hammer and gave it a couple of taps. Well it was seated and it broke off the rim on the top of the magnet. I said oh crap, but it did seat it Low enough, so I left it. Been running great ever since. Anyway with your Petronix I'll bet you just have a problem with the gap on the pickup. Here is how to test a Petroxix http://www.jalopyjournal.com/forum/t...tronix.363494/ BTW as well as mine runs, I still keep the old points plate and a screwdriver in my boat glove compartment, just in case LOL.

 

[BillysBoat1986]

Thanks for that link! I was about to return mine. I know that I had the sleeve seated all the way and I set the gap with the clear plastic piece. That sleeve was a booger getting it back off the shaft.

 

[BillysBoat1986]

Got it running! Timing and dwell is set. It runs smoothly..... Just gotta fix a bit of a water leak in the exhaust and she will be ready for the water!

 

[BillysBoat1986]

Thanks you all! You are top notch!