pontoon won't start

boatman37

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So my mother and step-father have a pontoon they bought last year. They have been having trouble a few times this year with a dead battery. I knew they had 2 batteries but did not know they had a Perko switch installed. I thought he just had the 2nd battery and manually switched it. Anyway, we were going to go out on their boat today and it was dead. I went down to look and found that they had a local marina install the Perko switch He had a charger hooked up to what he thought was #1 battery (the newer battery) so I asked him if he tried starting it on #2. We tried it and it fired right up but stalled after about 15-20 seconds. After that nothing. No click, no power trim. But the depth finder and horn worked. We checked the emergency cutoff switch and it was in the Run position. We removed the older of the 2 batteries and put the charger on it and it read 1% charged. The other battery was still in the boat and connected and read about 98% charged but still could not get any click or anything no matter what battery position the switch was on. I'm thinking the old battery is bad but confused as to it not starting after we disconnected the old battery. Checked for breakers and couldn't see anything. It has a Merc on it if that matters. Even tried wiggling the throttle around to see if it might be the safety switch. Told him to take both batteries and get them tested but pretty sure the original one id bad. It came with the boat when they bought it so no idea how old it is. The other one was bought new last year.

Thoughts?
 

alldodge

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I'm thinking this is an outboard (Merc) and if so should be in the Merc outboard section. You have an electrical issue, but the issue is the motor will not start, so its a motor problem. You'll get more folks looking this way.

If you agree, PM or put a mad in your comment so they will see and move the thread

If one bat is dead (or close to it) and is connected to a good bat in parallel, the bad one can damage the good one. Have the good bat off the charger for an hour, then load test it
 

boatman37

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Yeah. thats what i was thinking. I didn't put it in the Merc section cause its an electrical issue? I told him to get both batteries tested then go from there. It did this a few weeks ago then he charged them and it ran fine last weekend. Now today its dead again. I was thinking the bad one would be pulling down the new one
 
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Silvertip

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When you removed BAT #1 you likely eliminated the ground connection to the engine from battery #2. Only guessing at that because I don't know how the grounds were connected. Just because there is a cable on bat #2 NEG doesn't mean it is connected at the engine block.
 

boatman37

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Shouldn't have. The one I disconnected had the ground jumpered to the other battery so the remaining battery had the main ground connection. He was supposed to take both batteries to get tested today but haven't heard from him yet.
 

boatman37

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So they haven't been down to the boat for a few weeks but the shop owner came down and swapped out the Perko switch and said it was fine now. They went down today and nothing. So I took my voltmeter and started checking. Both batteries were at 12.60 volts. Power at the one terminal on the solenoid was 12.6ish. Checked the other post while he hit the key and nothing. So jumped the solenoid and the engine cranked over. Turned the key on and jumped the solenoid again and crank but no fire. So I'm thinking either the kill switch is bad or the ignition switch is bad?

Also, another oddity is the power trim won't work either at the throttle controls or using the button on the engine itself. Worked fine before. Not sure how these would be related but seems odd.

So thoughts? He is going to call the shop gain tomorrow but I'm pretty sure it is a problem in the throttle controls with either the kill switch or ignition switch? I guess still possible the solenoid id the issue but with the key on and jumpering the solenoid it should have started if it got a 'run' signal from the ignition?

Coincidental that this all happened after the shop installed a 2nd battery and Perko switch. They also installed a new stereo but can't see where any of that would have affected this? Feel bad for them. They bought the boat last year and I think they had it out once this year. every time they go down it won't start.

And FWIW the ignition key is a Quiksilver. Not sure exactly what controls they are but it's a merc and you have to push the key in for choke and lift the lever above the key for fast idle.
 

alldodge

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Need info on the motor, what year, assume Merc from key being QS?
 

boatman37

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yeah. Merc 40HP 3 cylinder. don't remember much more about it though. The boat is about a 2003ish so assume the motor is similar vintage. it is a 2 stroke oil injected
 

alldodge

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The wiring diagram is in this area. Still think you could get more folks to help if this was in the Merc outboard section. It has ones with and without oil injection and push to choke.

A racerone jerryjerry05

http://boatinfo.no/lib/mercury/manuals/40-50-55-60.html#/106

Just the starter wiring is here and the next page has the trouble shooting guide

http://boatinfo.no/lib/mercury/manuals/40-50-55-60.html#/86

Here is the control handle

http://boatinfo.no/lib/mercury/manuals/40-50-55-60.html#/110
 

boatman37

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So the shop owner still hasn't shown up. We pulled the conduit off the control cables at the box and there are some wires that look melted. Step-father mentioned that to the shop owner and he said he doesn't want to get in the water to replace it so will have to do it after they pull it out but said he can run temporary wires to get it running. So looks like they may be done for the season. They spend most of their time at the dock hanging out with friends anyway and we have taken them out on ours so they aren't too upset about it.
 

boatman37

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So step-father went down today and found a blown fuse inside the engine cover. He replaced it and the trim worked. Hit the key and it cranked then stopped. Checked and the fuse was blown again. There are bare wires that look like they are melted coming out of the throttle controls. Looks like he may need a new harness.
 

boatman37

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So the shop owner stopped down this afternoon. There is a big round rubber plug coming out of the control box. It looked like it came unplugged but I was afraid to tug on it too hard. The guy grabbed it and unplugged it and replaced the same fuse on the engine and the boat started right up. He said that plug runs the wiring for the helm. He said there were also melted wires under the helm. He said he has a used harness at the shop and it supposed to stop tomorrow to replace it. But the boat runs now with the plug disconnected.
 

boatman37

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Well the shop owner swapped out the plug coming out of the control box. Boat started right up. Guess that was it. We will see if it lasts. For reference it comes out of the control 'box' and has a round black rubbery connector. That is what he replaced.
 

boatman37

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Not sure what it's called. From what he said that plug has all the wires that run to the dash cluster. The round black connector is about 10" or so from the throttle controls. It disconnects it from the rest of the harness that runs back to the engine. I guess to separate the throttle controls from the rest of the harness? There were some melted wires on the engine side of that connector too so not sure if he did anything there. I'm going to suggest to my step-father that he have that whole harness replaced over winter just to be safe.
 

boatman37

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Well they went to the boat today and again no start. They are done messing with it this year. Think they are going to be pulling it soon. Told them to take it to another guy and have the whole harness replaced from end to end. I think they had the boat out twice this spring then since about the end of May it hasn't ran. They spent alot of money on a full canvas enclosure this spring too. At least they got to sit and hang out on it all summer at the docks.
 
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