Dead battery won't recover

rebmo

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Jul 2, 2007
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Today we took our Lund Explorer 2006 Sport 1700 w/115 Merc 4-Stroke out after doing a driveway muff checkup yesterday. The boat started right up in the driveway and idled for a while then I gently ran it in forward/reverse and all was well. Today launched it and started it and it started right up. Let it idle a bit and started to prep to take off.Then the motor died. I tried to restart and it just turned over (never did that always fired) We then noticed the lanyard switched had been bumped to off (ahah). So switched it to on and tried starting a few more times and it started to fire but then the battery went dead. It was flooded I assume since I could smell gas. So let it rest a while and it just clicked. Battery is going on 4 years but always on a maintenance charger.

So not to far off the launch, we fished a bit and then trolled in. I parked on the other side of the launch dock and switched to a healthy trolling battery. All I got was clicking. Next I phoned my wife and she came down and picked up the battery and me and we went home (close) and charged the battery. Voltage was at 13.5 when I took it back and installed it gain and all I got was clicking.

So something else happened here. Tried 2 batteries One good for sure (trolling battery with near full charge according to trolling motor monitor) and the other (starting battery) fully charged. Checked connections all clean and rock solid. Now all I'm getting is the click. Any suggestions on what to check.

One note is that the ignition switch seemed to turn further than the start position. This evening I took it out and checked it and it may have just been loose in the dash. I could not get the switch guts to turn with the key holding the switch body in my hand and turning the key. So it seems fine. It seems like I have some electrical issue brought on by whatever happened today.

Any thought starters on where to check? I'm going to go through fuses Thursday when I get the next chance to check it out in daylight.

TIA for any thoughts.
 
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rebmo

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Jul 2, 2007
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Turns out the Starter for the Merc 2006 115hp 4-Stroke with only about 40 hrs on it is shot. The top cracked on it and who knows what else. I ordered a replacement from the Lund dealer near me and of course they ordered the wrong one. They looked it up again and ordered the correct one. Turns out these Merc starters must have a huge fallout since this is a retrofit replacement kit. There currently were only 4 available nation wide USA. Roughly $500 at that for a replacement for a failed starter design from Merc.
 

rebmo

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Jul 2, 2007
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So its worse. The motor is locked up. Pulled plugs and found gas filled the lower cylinder and hydra locked it. Doing some google searching found the "making oil" symptom is related to this. There is a vacuum line/tube in the fuel regulator that ruptures and either adds gas excessively to the oil or in my case fills the lower cylinder and locks up the motor. So I drained the gas from the lower cylinder, checking the piston travel in case the lower rod is bent, draining all fuel, pulling the fuel regulator to investigate the root cause of this disaster. Once I confirm the cause, I'll changed the oil, filter, & plugs, and if the rod is not bent, try to fire it up.

Anyone else have this issue?
 
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gm280

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Jun 26, 2011
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WOW rebmo, sounds like you experienced it all in a short period of time. I hope once you get all those issues settled, it all run good for a while. Amazing how things avalanche on each other some times.
 

rebmo

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No Title

Yeah, not my way of enjoying my boat. Not really happy with this Merc 4-stroke based on what I just found. Thought I had a reliable motor with only about 40hrs on it, but one cheap part really brought it down.

I pulled the fuel regulator today and sure enough the cheapo Mercury vacuum hose inside ruptured (this is the problem I found googling). This can also result in "making oil" if the hose rupture is small and just sucks up a little fuel to flood a cylinder and add fuel to the oil - nice design mercury) This ruptured hose is said to suck up the fuel into the intake and also load up the bottom cylinder. Exactly my problem. The intake and lower cylinder was loaded with fuel. Engine turns over nice & easy with the plugs out and tdc distance is consistent so looks like no bent rod. I really can't believe such a cheap flimsy hose is used for vacuum internal to the fuel regulator, shameful. So now I need to get some 1/8" high pressure ethanol safe injection hose (recommended by those fixing this unreliable cheap merc hose).


Attached is a picture of the failed vacuum hose from the internals of the fuel regulator. It's unbelievable shredded.
BTW, I did use Merc fuel preservative and also treatment run into the system at the end of the season. That said, the fuel still smelled a bit varnishy. I think I need to switch to a reliable fuel conditioner also.

The 2 shredded ends of hose in the picture are meant to be joined together. ("u-shaped")
 

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GA_Boater

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Lets move this to the Merc OB section. More guts will see it and give advice, rebmo.
 

rebmo

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Jul 2, 2007
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Thanks, Sorry for putting it in the wrong area.
Oh and also, noticed a chunk of foam missing from the air filter. Come to find this is also a Merc OEM problem. The filters deteriorate and chunks get sucked into the engine. Luckily only a fingertip size piece was missing from mine and I'll have to replace with the new one. I don't know the year this problem was discovered but I still had the defective Merc design air filter. On to the new. Any other defects on this motor I need to fix while I'm on a roll here.................
 

rebmo

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Jul 2, 2007
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I contacted Mercury and basically they said sorry to hear of your problems with our motor design defects and sorry we won't help you in any way. Oh, but there are updated replacement fuel lines available that we will be glad to sell you for full profit to fix our poor designs. So much for Customer service. Oh well buyer be aware. I hope after I get this fuel regulator hose defect fixed and the defective OEM air filter replaced at $80, I will have a running engine. Are there any other design defects I need to be aware of and fix on these motors as long as I have it down?
 
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rebmo

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Jul 2, 2007
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Yesterday I installed the new fuel regulator hose. I noted the old hose was rated 8.6 Bar - 125psi, and the new one 33.5 Bar or 486psi (Quite the pressure rating increase). I had decided to go with the Merc replacement since it's a replacement for the hose that blew, not the original lower rated hose. Install was pretty easy but requires placing the hose in 150F minimum water to soften for install. The kit also contains 2 Oeitker clamps which work well and should not come loose. I do have an Oeitker clamp crimp tool which works great.

Now I need to put the fuel pump/regulator assembly back together and attach the external hoses. Unfortunately it's raining but will get to it over the next couple days along with new plugs & oil. I did pump out the 1 year old preserved fuel and disposed of it. I have fresh non-ethanol fuel in some 6 gallon jugs that I'll fill with before I fire it up. Hopefully no more issues but at this point who knows.
 

rebmo

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Jul 2, 2007
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Surprisingly those wire connections are submerged in gasoline. The line that ruptured is actually a vacuum line that comes from the intake manifold and attaches to the fuel regulator diaphragm. The vacuum line actually runs through the gasoline also. When the line ruptures it sucks up fuel (from the vacuum coming from the intake manifold) and it goes right into the intake manifold. This loads the manifold with gasoline and it gets sucked primarily into the lower cylinder. So much fuel gets sucked into the cylinder if fills it to the point where the motor will not turn over (hydra locked). A small rupture of the hose could constantly suck smaller amounts excess fuel into the lower cylinder(s) and wash down the cylinders and dilute and add fuel to the oil. Great design huh?

Some research on the connectors in the fuel and that's actually a common practice with fuel tank sensors and other connections such as this submerged in fuel. Evidently liquid gasoline is a very poor conductor such that the low voltage is not a hazard. Still scary to me........
 

CWKboat

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I contacted Mercury and basically they said sorry to hear of your problems with our motor design defects and sorry we won't help you in any way. Oh, but there are updated replacement fuel lines available that we will be glad to sell you for full profit to fix our poor designs. So much for Customer service. Oh well buyer be aware. I hope after I get this fuel regulator hose defect fixed and the defective OEM air filter replaced at $80, I will have a running engine. Are there any other design defects I need to be aware of and fix on these motors as long as I have it down?

So much for "agree with thine adversary quickly" and "go the extra mile" when offending a brother or customer in this case.

Companies can be so penny-wise and pound-foolish as who would want to buy new from a company after this experience.
 

rebmo

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Jul 2, 2007
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Put the fuel module back together (with the new $20 failed vacuum hose replaced) and all the connections back together. Put the "old spark" plugs in temporarily, fresh fuel, oil, etc.. and she fired right up and idled perfect and ran the rpms up a bit in gear with muffs on and full pee going of course. Ran the old plugs first to burn off the oil added and any crud from the lower cylinder. Tomorrow I'm going to put the new plugs in with anti-seize loctite and loctite the coils in. Checked for leaks and all is good. If I get time I'll put it in the water and see how it runs out.

Hope this thread helps others with Merc 4-strokes bound to have this hose fail sooner or later.
 

rebmo

Seaman
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Jul 2, 2007
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Put new plugs in and it ran perfect. I hope the new vacuum hose can hold up and doesn't leave me stranded again. I have to wonder how many others have had this issue and had the "making oil issue" that they could never figure out, or took it to the dealer to spend big $$ to get their motor fixed when only a $20 vacuum hose? These quiet design fixes really make me consider ever buying this brand again. For now I'm stuck, but next time...........
 

ondarvr

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Apr 6, 2005
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It's nice to see you that followed through and reported the fix, many people don't, which leaves all the future people that experience this problem very little information. Thank you.
 
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