Bad Coil

[SteveO]

Have a 21i with the MP 340HP 5.7L. It died on the lake a week ago. We confirmed that it had no spark. The technician ordered a new coil. We installed it and back in business for a couple hours until it died again the next day. This time the tech came out and worked on the boat for a couple hours. He cleaned all ground points and got it going again. An hour after he left it died again and had to get towed in for the third time in a week. All ground points cleaned and tightened. No spark. Have 12V going into the coil and out the coil wire but no spark? We opened the MP box and found corrosion on the fuses and the circuit card traces. We cleaned everything but still no spark. The dealer is ordering a new board from MP. Anybody have similar circumstances?

[chpthril]

Have a 21i with the MP 340HP 5.7L. It died on the lake a week ago. We confirmed that it had no spark. The technician ordered a new coil. We installed it and back in business for a couple hours until it died again the next day. This time the tech came out and worked on the boat for a couple hours. He cleaned all ground points and got it going again. An hour after he left it died again and had to get towed in for the third time in a week. All ground points cleaned and tightened. No spark. Have 12V going into the coil and out the coil wire but no spark? We opened the MP box and found corrosion on the fuses and the circuit card traces. We cleaned everything but still no spark. The dealer is ordering a new board from MP. Anybody have similar circumstances?

Sounds like a bad pick-up or ign module. Both can quite working when hot. One side of the coil primary should have 12 v's and the other should have a ground pulse while cranking.

[SteveO]

Yeah - the boat did go through a series of starts and cut off's after getting hot before it died for good. What is the module that hangs off the coil assembly that it attached to a heatsink? Is that the ignition module?

[chpthril]

Yeah - the boat did go through a series of starts and cut off's after getting hot before it died for good. What is the module that hangs off the coil assembly that it attached to a heatsink? Is that the ignition module?

Yeah, that sound like the Ignition module. does it have a couple of plugs going to it? maybe a 2 wire and a 3 wire if I remember right

[SteveO]

Yes - just a three wire.

[chpthril]

Any update there SteveO ???

[deltaboy1960]

start stall after hot

i have a 21v 5.7 liter have a start stall after hot getting i just hold key down longer will start but now have to let cool off thinking ing module any help

[deltaboy1960]

[QUOTE=deltaboy1960;79432]i have a 21v 5.7 liter have a start stall after getting hotijust hold key down longer will start but now have to let eng cool off before it will start thinking ing module anybody help]

[R&T Babich]

Is there no spark at the end of a plug wire or the distributor wire going into the cap? None at the cap would probably be an ignition module. None at the plug wire could be a cap/rotor. My bother-in-law had a 350 truck that we changed everything on - coil,module,rotor,wire. Three people inspected the cap and could see no flaws, cracks, carbon or anything. Replaced the cap "just because" and it's been running fine ever since.

[dogbert]

Distributor caps are known to go bad. The Mercruiser 350 Tournament Mag is notiorious for this problem. You pretty much have to replace it every 2 years.

[Jasfarrar]

I had the same issue this weekend. The vents below the windshield were broke and I fixed them. Ran the blower the whole time, Fuel pressure never drops when it starts to sputter, and temp gauge never goes up. Any other ideas? Someone said a Coil? Seen some other threads about a distributor cap? The boat would run fine if I left the engine cover propped open, which I did for the rest of the day. This is so aggravating. Hope someone can help!!