Radio causing boat to not start

[rad1026]

Kind of off topic I know, but you guys are the best so I'm hoping you have some ideas for me. After getting some work done on my old 89 Chaparral the boat has been running better then it ever has. I have been away from the boat for two weeks and I got her in the water a couple days ago and she just cranked and cranked and wouldn't start. I started with the battery, checking tight connections and the positive terminal was really hot. I disconnected the battery and let it cool. I hooked up just the large cables for the starter and cranked her over and she started right up. I ran her for a few minutes and had no problems with the battery getting hot. I reconnected the accessory terminals that run the dash board, bildge pump, blower, horn, lights, etc. Started up the boat no problem. The battery terminals were cool and she ran great. Then I hooked up the wires for the radio. Turned on the radio and the radio works fine. The battery terminals remained cool. I turned the key to accessory and still everything worked fine, not hot terminals. As soon as I try to start the boat with the radio hooked up the positive terminal gets hot and the boat won't start. Obviously I have a short somewhere, but why would the radio work fine until I engage the starter? I just don't know where to start here? Any thoughts would be greatly appreciated. All the wiring has been the same since I got the boat and have never had any problems like this before. Thanks Guys!

 

[Bt Doctur]

Re: Radio causing boat to not start

radio has no effect on power, something else must be happening

 

[EddiePetty]

Re: Radio causing boat to not start

.....assuming that all of the electrical connections (at least on the positive side of the battery) are to a common post, I would suspect dirty ring terminals on one or more of the connections.

 

[glenn property of pam]

Re: Radio causing boat to not start

weird things happen but there's always a reason. Firstly any time you crank a motor and it will not start the terminals will get warm so I would not be surprised if a engine that started in 10 seconds was cooler on the terminals than one that was cranked for 30 seconds. heat is a sign that power is struggling to cross a point and is converted to heat so my first suggestion is to clean all the large terminals including the grounds especially at the engine block (this includes the bolt area the ground is attached to the motor)
leave the radio disconnected for now until you are sure that everything else is working fine. Then you will need to trace the power wires (2 of them) to where they are attached to the boat wiring. One sounds like its at the battery and should be fused with in 6 inches of the battery positive (make sure that its fused and a clean connection) the other is connected to ?

 

[rad1026]

Re: Radio causing boat to not start

well it was a strange wiring set up I thought. There was a 12V 20A fuse attached to the positive battery terminal. On one side of the fuse was the wire that powered the dash accessories. On the other side of the fuse was the wire that powered the radio. Very strange set up because the fuse did not seem like it was protecting either component the way it was being used. It really only seemed like it was being used as a power source for each component. The fuse was fried and melted but I don't know if it was because of the heat or if it shorted out. I removed the fuse and connected the component wires directly to the positive battery terminal until I can replace the fuse, but it didn't make any difference on the effect.

 

[glenn property of pam]

Re: Radio causing boat to not start

help us help you. One side of the fuse was connected to the battery then on either side was to separate items......well that makes 3 sides on a fuse which is confusing. Do not connect anything to the battery that is not fused especially if you have a problem that's blowing fuses. Fuses do not melt when put near something hot they melt when there's a problem.

 

[rad1026]

Re: Radio causing boat to not start

exactly, I know the set up was not right, but in all honesty I never really looked at it that close because it never gave any problems. Now I have to track the wiring down and figure out why it was wired that way, why it got hot when it did and what is causing the battery terminal to get hot. I know its hard to diagnose someone's 20 something year old wiring problem. I will be back down to the boat on Wed. afternoon and see if I can get it figured out Thursday.

 

[Bondo]

Re: Radio causing boat to not start

exactly, I know the set up was not right, but in all honesty I never really looked at it that close because it never gave any problems. Now I have to track the wiring down and figure out why it was wired that way, why it got hot when it did and what is causing the battery terminal to get hot. I know its hard to diagnose someone's 20 something year old wiring problem. I will be back down to the boat on Wed. afternoon and see if I can get it figured out Thursday.

Ayuh,.... It's gettin' Hot, because of added Resistance,...

Start by cleanin' to shiny metal clean the battery terminal, 'n those wirin' ends,...

If there's a Wing-nut on that terminal, Toss it overboard, 'n get a real nut ya put on with a wrench, 'n tighten it...

When chasin' electrical gremlins, Heat is yer hint that, That's where a Problem is,....

 

[Grub54891]

Re: Radio causing boat to not start

When ya have to many wires running to the battery it's pretty easy to get em mixed up,people put in the wrong color/non marine grade wiring and it caused them issues. I always recomend a accesory buss bar (fused) installed for them extra wires,one time hookup and easier to maintain.
Grub
P.s. ABYC says no more than 4terminals on any one lug,but I do not like any extras on there....well the bilge pump is ok to have on there.

 

[rad1026]

Re: Radio causing boat to not start

Finally got back to the boat this past weekend. Started off cleaning all battery terminals and connections. Put her in the water, started up just fine, no heat, no issues. I really have to do a better job of those little maintenance issues. Thanks guys!