OX66 LP Fuel Pumps

fishinAK1

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A bad coil or corroded coil connections?
I cleaned the coil conntions up very good before the swap. Feel pretty confident it’s not the connections. But it is curious the faulty coil also seemed to be the one w the most salt crust. Idk

full disclosure, a couple years ago the line that connects to the port that the water pressure gage is connected to (at top of cylinder #2) had a small crack and was misting the outboard with saltwater spay for a few trips. After this I removed the water pressure gage and plugged that port! I cleaned up the salt best I could, but may have missed a connection. Coincidentally, this port is on same side as corroded coil Connections....
 

Sparkdog118

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Nice. . The wire is part of the coil, but the coil ens with the resistor is sold separately. These are the Yamaha part numbers you need. Are 61a-85570-00-00 (coil) and 6e3-82370-21-00 for the resistor end. It is probably just the coil that is bad, but you can replace both of you want to be on the safe side.
 
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seasick

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Plug wires and boots are easy to check.

Plug wires could be swapped between 4 $ 6, they are the same length I think

It's probably a bad coil though. In this case, I say " buy the part"!
 
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fishinAK1

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Thank you I ordered a new coil assembly, when it gets here and I get it installed, I report back.
As much as I hate paying shipping and waiting for parts, I have to admit it’s gonna be nice to step away from outboard work for the weekend.
Hope you all have a good one!
 

fishinAK1

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I promised Id report back. Unfortunately, I reporting back even more frustrated than ever.

After diagnosing a bad coil last week, I ordered a new coil. paid the $57 to AK (OUCH) and installed the coil this morning.

The outboard seemed to run fine at idle. sounded a little smoother than normal (maybe). But as soon as idled out of the harbor and tried to get er up on step it was like there was no throttle past 1500 rpms. I went back to neutral and tried again. now it got up on step but then dropped rpms again, then surged. then dropped. ...generally ran like CRAP, worse than it ever has. I got back to the dock, popped the cowl, and started peeking around. I thought I heard hissing sound I haven't noticed before but could be my imagination.

Then, while still in neutral, I throttled up. All of a sudden I noticed a small wisp of smoke (oh shi!t!). then a small FLAME! I immediately shut er down! Looks like the thick bundle of wires that run between the CDI and the injectors (via behind the VST and across the LP pumps) started to melt. Ill post a crappy pic.
ARRRGGG!!!

I assume there must have been a short in one of those wires. it was lightly raining when the cowl was off. could that have started the arc/heat/fire?

Could this have been why the injectors were running rich to begin with? Could the CDI be bad? How do I test the CDI? I cant find this wire bundle anywhere online. Does anyone know if I can order a replacement?

one other thought. This weekend (while waiting for parts and taking advantage of nice WX) I spritzed the outboard down with Boeing T-9. Perhaps a wire was arcing and ignited the T9?

also...the small flame seemed to extinguish itself as soon as key was shut off.
OMG this is Killing me!

Thanks for any and all help!
 

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Sparkdog118

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Oh no. That is terrible. I had a motor once with a bad intake gasket that was backfiring out the side of the block. It ended up burning the engine harness and shorting the wires like what you are experiencing. Now that #6 is now firing, look behind the area that is burned to see if it is now blowing out the side of the intake gasket near #6 reed. Just a thought. If the ecm is the culprit, the back jell of the ecm will smell burnt n have a small crack or pit. If it checks out, the harness may be temporarily repairable if you separate all the wires. cut out the bad sections of each wire and splice new wire to bridge the burned area. Check the rest of the harness for any other bad areas. Put the key in the on position, and listen for the fuel pump to kick on in the vst. Leave key in for about 10 sec n check the temp of the wires. If they seems cool, start it up and watch for a block leak thru the intake and temp of the wires. Not much to lose here. Not thinking t9 or rain is a cause.
 
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fishinAK1

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good thought Sparkdog. Thanks for your valuable insight!
One question though. If the intake gasket were blown out, wouldn't I have bad compression on that cylinder?
last I checked (at the beginning of this whole debacle) compression was good (between 115 and 120) in all cylinders. Maybe time to recheck compression...

Thanks for the advice. I sincerely appreciate it!

Hopefully, this thread will be valuable to others in the future too. lots of 'great advice on here!

Oh shit. I just had a thought after reading your response. I wonder if the "hissing" I thought I heard could have been from a hole in the gasket...
 

Sparkdog118

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Happy to help. Compression will not be affected at all by a bad intake gasket or reed. I have checked compression with the intake completely off n it still comes out to spec. Also check the gasket behind the low pressure fuel pump. I know they r new, but still check since that is where the wire was burned. I tried to post the wiring diagram for your fuel system, but I can’t get the pics to load. I have the whole oem repair manual with diagrams for almost every Yamaha.
 
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fishinAK1

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Ok, I pulled that bundle of wires. I'm gonna solder a bridge between the couple bad spots.

Upon closer inspection, it looks like the flame was right on top of the bottom (of 2) low-pressure fuel pumps. I can see burn marks on top of one of the stainless screws. maybe it was arcing to this screw? it's it possible there are gas fumes from this brand new pump that ignited? Should I change this pump out AGAIN?
I don't see any obvious gaps in the intake gaskets and honestly, the bundle of wires was quite a way away from the block.

It looks like the culprit wire was the red & yellow wire that begins the injector chain and then runs all the way over the top of the fuel pump resistor assembly cover and ends at the relay under the fuse box. Is this the fuel pump relay?

Question IS. was it just a bad spot in the wire that finally fully shorted? OR is the relay bad could is send too many amps the wire and melt it AND all wrapping tape? Could this be why the injectors had been running rich? Is there a way to test that relay?

One more note: Before i noticed the flame, I was gonna pull the spark plug boots to see if the new coil helped. After pulling one boot, as I went to push boot back on I got a shock. I just assumed this was because the boot was wet (rain). Could the rain and loose plug boot have been "charging" the block and thus grounding to that bundle of wires?

Ok one more thing. When I was just removing the air silencer to pull that bundle of wires. I noticed a fair amount of water spill out of it. And the little bit of oil that is typically near the bottom cylinder was a creaming light green color. Is it possible that rain had collected in the air silencer and was being sucked into the cylinders or maybe via that little vacuum hose? I assume that would cause the running like shit that I experienced before the flame.

Sorry lots of thoughts.... But lots going on! I know if Seasick reads this his "head will spin"

Again thanks for any thoughts!
 

seasick

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Getting a shock from pulling a plug wire is 'normal' and doesn't mean at all that the wire or boot is bad.
If you had water in the intake, the motor would emit white smoke and potentially a lot if there had been a decent amount of water probably not an issue at this time.

Wires in a marine application according to ABYC should not be soldered. They must be mechanically connected (crimped with butt connectors with adhesive lined insulated connectors). I suppose you could try to solder to see if the motor runs but you would have to crimp later or replace the bad harness. If you crimp buy a good ratchet crimper tool, not the cheap one at HD.Buy good connectors also, like Anchor.
It is possible that the flame you saw was not a fire but the arc from a short to ground. Normally I would expect a fuse to blow. For now check all wires, separate any harness group that are suspect and repair.
If you had a short that shot a 'flame' that may have caused burning or damage in other places. It depends on what power source got shorted.

Since this was all new after replacing the coil, I would think that you may have accidentally squished a wire or harness. Perhaps a harness got put into the wrong place and got rubbed by some moving part.
As to a leaky pump; I guess a leak is possible but in general it wouldn't catch fire without something igniting it. As the Boss said ; "Can't start a fire without a spark"

It's not the relay, it would not cause excessive current draw.

I am curious; Did you run the motor on shore or a the dock or did you just replace the coil and go out to sea? Was the cowling off?
Don't go replacing a bunch of parts until you know if and how bad the motor may have been damaged.
 
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fishinAK1

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Well damn. I just soldered up and heat shrinked all the bad wires. Thought this would be better than butt splices....

I first ran in a bucket for a couple minutes then went down to the harbor. The cowl was off for a bit while installing new coil. And then again after the first run around. But not while running. Yes, it was raining. It did get wet.

Well not real sure what to do now. Wires solder back together. But nothing else has changed.
Try again and keep eye out warm wires I guess...
 

fishinAK1

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Looking at the CDI, I don’t recall seeing those 2 bumps on the right protruding out.
is that normal?
 

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DennisG01

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AK, I just wanted to add that Seasick is correct in that it's not a good idea to solder connections. It actually is "OK" to do it according the CG rules, but you must secure the wire on either side of the solder joint so it can't vibrate. See, that's the whole problem - vibration - it's very hard to solder a joint "just right". What happens is that right where the solder stops (and most will use too much solder, making it worse) you end up with a weak spot in the wire. You create an area will ALL bending and vibration will take place... and you know what happens when you bend something in the same place over and over. Which brings us back to the best practice is actually to use crimp connections. It's not going to break overnight, so don't stress about it. Just remember to fix it sometime.

Are you talking about those "half an octagon" shapes? I don't recall what mine looks like well enough, but they certainly look normal. I guess googling for some pics would tell you pretty quickly.

FYI, I don't think you caused the problem by running with the hood off. A little bit of rain isn't going to hurt anything. Unless there was a problem that was just about ready to happen anyways, and the rain hastened the process. But don't beat yourself up on that - you didn't do anything wrong there.