No spark, No Fun

Road King Cole · #1 11-10-2009, 09:07 AM

Well, I hoped I wouldn't be posting in the repair section this soon, but here I am. I was so excited to have yesterday off to try another day of fishing in abnormally nice weather with just me and my dog. After launching the boat, my 470 mercruiser wouldn't start. Once in a while it would stutter. I checked the points and they looked good. Pulled a plug and broke it. Noticed it had gas on it and looked old. Checked the boat and no spare plugs. OK, put the boat back on the trailer and off to Napa. Napa was no longer open they directed me to the only other place which was auto zone. They only had one plug (typical, I hate autozone). Thinking that it may have just been flooded, I went back to the boat ramp and put the plug in. Still wouldn't start (Yes I learned to make sure the engine starts before taking it off the trailer).

Now that it was getting late, time to give up and bring it home. Took the bike to a real parts store and got a complete set of plugs.Put those on, still won't start. Get the wife to turn it over so I could check for spark on a plug. Only saw it spark once after many turns. Although the points looked good, I remember seeing a tune up kit (dist-cap, points etc). Turns out the cap was used but there were new points and condenser. So I put the new points and condenser in (the dist-cap looked fine). No change. Had the wife come out and turn it over with the cap removed and I was not seeing any spark at the points.

Unless I missed something, I am thinking it has got to be the coil. I wished I had thought about making sure it was getting voltage last night before it got dark.

Right now I am sending the wife out to get a new coil and maybe try putting it in tonight so I can sleep better. If I get it running, maybe try going out again on Saturday…and just maybe my crabs will still be alive.

Is there anything I might have missed?

Sorry for the long post...

thanks,

rkc

Road King Cole · #2 11-10-2009, 09:48 AM

I was told by a co-worker that I wouldn't see spark with the dist-cap off. I am used to seeing spark working on my old bike (which doesn't have a dist-cap).

I still should have seen a good spark at the plug....

RWilson2526 · #3 11-10-2009, 11:22 AM

I had a similar problem on my 3.0 on my old boat.....not sure if yours is set up the same but the tach gets it signal off the coil, I had a short in the tach that was killing the spark. After replacing the distributor, points, plugs, plug wires and coil I finally disconnected the wire from the tach to the coil and it fired right up.

Road King Cole · #4 11-10-2009, 01:33 PM

Thanks, that was a "good one"...

I heard the shop had to order a coil which will arrive tomorrow. So I will wait until tomorrow night to get back at it.

THEFERMANATOR · #5 11-10-2009, 02:17 PM

The first thing to check with ANY boat with an ALPHA outdrive is the shift interrupt switch. It isn't hard to disconnect it and it rules that portion out.

spareparts · #6 11-10-2009, 06:22 PM

after you disconnect the shift interupt switch, check for voltage at teh + terminal on teh coil, you should have around 12volts cold, after it warms up the voltage will drop from the resistor wire in the harness, if you have voltage and the shift switch isn't grounding the coil, remove the cap, bump the motor over, you should see sparks at the point contact, if you don't, bump the engine over till they are closed, and rub the contacts together, you should see some sparks at teh contacts, put everything back together, don't forget the rotor, and you should have spark at the plugs. DO yourself a favor, replace teh points with a pertronix conversion kit, its easy to do and the engine will run better, you won't have to worry about points again