Engine fell on its face underway. J90TLCOS

[OFF THE CLOCK]

Ok this is the issue. Engine was running 4400 rpm on plain lost power (cut in out in out). Never died, put throttle back to idle stop position. Engine idled with slight shake. WOT never regained speed or thrust. Removed all fuel checked fuel water none present. Removed carburetors checked jets both no issues compression even 125psi x4. Started engine in a tank will idle won't start right up but it will and will idle.

While on trailer @ ramp WOT you could hear the engine cutting in and out (one side or another coming alive) but still not full power. Running boat down the ICW shut key off engine would still run (less power) turn key on (1/2) power back to original issue. So it is safe to say there is an issue in with the key switch wiring. Now that being said I guess the key switch being in the off position it was in fact putting a charge to something while sitting in the driveway waiting for the next outing. So what do you think was cooking while the battery was hooked up? coil coils under flywheel, Now I also replaced the power packs and all coils (have 3 sets of them) spare parts. Checked all wires in and around harness for breaks and corrosion. Went completely through inspected all points everything appears to be intact. Will idle slow to plain no power. Like I said this happen while under load @ 4400 rps on plain. Engine ran fine up to this moment still running somewhat above idle to plowing will plow WOT nobody's home so to speak. Have manual, fully tooled will go through the checks of resistance's etc troubleshoot parts electrical. Looking for the reason and what you might test first thanks.

 

[AEROCOOK]

Water in the control box? Did it get rained on? Try disconnecting the yellow / black kill wire at the powerhead and see if the condition improves.

 

[schematic]

a failed rectifier/regulator can cause burnt coils under the flywheel. It can also cause driveability issues as well....

 

[emdsapmgr]

Suddenly losing power would be more typical of an ignition problem. When running and the engine is fully warmed up-check for spark on each cyl. If you can-have the engine under load when checking. If it's in the lake, shift it into forward and let it idle. That engine has dual identical power packs-one for each head. If you find you have no spark on one head, swap the power packs for testing purposes. See if the "no spark" condition moves to the other head. 1985 crossflow. I've also seen a defective power pack fail to shut off when the key switch is turned to off. That can keep the engine running on one power pack (2 cyls.)

 

[OFF THE CLOCK]

a failed rectifier/regulator can cause burnt coils under the flywheel. It can also cause driveability issues as well....

I called the boat part store and asked them about the coils under the flywheel they said it don't have coils under there. But As you stated it dose and I know it dose as well.

 

[OFF THE CLOCK]

Suddenly losing power would be more typical of an ignition problem. When running and the engine is fully warmed up-check for spark on each cyl. If you can-have the engine under load when checking. If it's in the lake, shift it into forward and let it idle. That engine has dual identical power packs-one for each head. If you find you have no spark on one head, swap the power packs for testing purposes. See if the "no spark" condition moves to the other head. 1985 crossflow. I've also seen a defective power pack fail to shut off when the key switch is turned to off. That can keep the engine running on one power pack (2 cyls.)

I did replace the coils x4 both power packs and had the same issues. And finding out there is a issue with the key switch. I'm not sure what made me turn the key off while running but I did. That's when I found an issue there. I called the parts house and asked them about the coils under the flywheel they Marine parts outlet told me there are no coils under the flywheel. However I know there their. I had an old Starflight apart and remember seeing them molded into the stator this is the same coils right? I think that something finally went bad In knowing the issue with the key being in the OFF position there was in fact a charge going to something. In the past I made up a key switch with a old pigtail off a old OMC harness so I could plug it into the engine and stand at the rear of the boat with turn key in hand. With that said when I pluged it in the engine wouldent start at all. with the harness running in the boat it will. So something was fried I'm thinking. Thanks for all the replys and help looking and thinking where to look and what to look at..

 

[OFF THE CLOCK]

Water in the control box? Did it get rained on? Try disconnecting the yellow / black kill wire at the powerhead and see if the condition improves.

Well yes and No. It did rain HARD right before this happen. but the cover was and is on the engine. When I took it out for a run right after the rain I had planned to do some fishing. The engine ran fine up the ICW. I tgurned around I overshot my fishing spot and when I got back turned around and on plain for no more than a cpl minuets and the engine freaked out. Hints why I originally thought water in the gas. Did a complete fuel service including carburetors still no dice..

 

[OFF THE CLOCK]

I do have a used but newer harness to replace the one there from key back to engine as well as a new key switch.

 

[emdsapmgr]

You are correct. There is a stator and a timer base under the flywheel. The stator is ringed with coils to make ignition voltage and to re-charge the battery. Think I'd be looking elsewhere for my parts, based on the advice you have been given.

 

[OFF THE CLOCK]

You are correct. There is a stator and a timer base under the flywheel. The stator is ringed with coils to make ignition voltage and to re-charge the battery. Think I'd be looking elsewhere for my parts, based on the advice you have been given.

This afternoon I was having a look at the wiring harness (engine plug side) and found the black and yellow wires (out to packs from engine harness) were so brittle they broke with a slight tug. I will first replace the harness (engine side) before I go any further. Either making up a new one with new ends. I'm good at wiring I just don't see spending that kind of money until I know in fact what happen either it being bad harness for a test I can butcher the old one save the ends at connection points ditch the rest. trouble shoot the electronics then replace harness and what else is needed. Thanks for the input will keep you all posted. waiting on funds stay tuned..!

 

[emdsapmgr]

The black wire with the yellow tracer is the power pack kill wire. Once the key switch is turned to "off" it ground out the pack(s) to turn the engine off.

 

[OFF THE CLOCK]

The black wire with the yellow tracer is the power pack kill wire. Once the key switch is turned to "off" it ground out the pack(s) to turn the engine off.

Thanks for your reply.

In researching the forms I've found a few more things out. 1 the blk/y wire the red plug was broken I think causing the engine not to turn off all the way one side.

 

[OFF THE CLOCK]

a failed rectifier/regulator can cause burnt coils under the flywheel. It can also cause driveability issues as well....

In reading the form I've also found a honey type under the flywheel one side. The harness is shot too. I'm undertaking the funds for a complete wiring overhaul. Just find it strange that the engine was running fine on plain at WOT then stumble cut in out and that was it. I"ve yet to check the firing issues the harness is NFG. and need to be replaced before I go any further. I have 3 sets of power packs 2 sets of coils for parts. Thanks again for your input.

 

[OFF THE CLOCK]

You are correct. There is a stator and a timer base under the flywheel. The stator is ringed with coils to make ignition voltage and to re-charge the battery. Think I'd be looking elsewhere for my parts, based on the advice you have been given.

Also in looking at the engine over the long weekend I've found honey under the flywheel. Looks like this is an issue as well. Counting my dollars on this one would love to know where the best place to get used parts from . Or good prices on new stuff.