Engine issue

dwna1a

dwna1a

Well-Known Member
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Apr 23, 2012
5,983
James River
Boat Info
88 Weekender 300 "Seahorse"
Engines
Twins 350
I know I have an electrical issue but I don't know. I think the alternator is gone, it sounds as if a bearing is shot. So it's coming out but when the engine starts it throws the 10amp breaker on the dash. Even if the engine doesn't it throws that breaker.

Any my ideas would be helpful
 
Throwing a breaker, like burning out a fuse, usually indicates a short on that circuit.
 
I will give both a try and report back on Monday. Thank you both
 
Yes, the alternator could be the problem. So could the connection on it.
You said that this happens after the engine starts. That means it starts and runs?
If so, I'll discount the possibility of an overheated starter caused by water in a cylinder. I've seen guys try to unknowingly start hydrolocked motors and think they had a starter problem. Sometimes the wires get so hot in that circuit from the strain the starter is under that they trip the breaker, or/and melt the battery switch.
But if your motor starts and runs, you don't have that problem.
Swapping the 10 Amp breakers at the helm is quick and easy. I had one go bad a few years ago, but when it did, it just went bad altogether and wouldn't send power to the motor at all. But since they are easy to get to, I would try swapping them and see what happens.
Take a good look at the connectors to the breakers while you're back there to make sure a connection didn't get cruddy and come apart.
One of the good things about twins is you have two of everything (except power steering pump). Try taking the alternator from the good side and moving it over. See if the problem moves with the alternator. They're a pain to get to, but it's a place to start.
Take a good look at the solenoid on the top of the motor too while you're in the bilge. Again, I've had them go bad on me before. They never tripped a breaker on me when they went bad, but they do go bad, so anything is possible.
The next place to look would be at the connections on the starter. They are the hardest to get to. A mirror and light might help you get a look to see if anything looks out of place. But being hard to get to also means that it's unlikely anything disturbed those connections, but it's worth a look.
If all else fails, you could try just looking at all connections, or wires that you can see, to make sure that nothing is grounding out. If a connection went bad and came apart, or the insulation wore through on a wire (less likely), you could have a wire grounding out against the motor or some other metal surface someplace.
Keep us posted on what you find.
 
She wants to start and run but as soon as the engine fires up the breaker trips. The alt has a bad bearing and will have to go, the breaker acts as if it has gotten weak. At times yesterday if you even turned the key on the breaker would trip. It may be just the two issues have just happened at the same time
 
Take the belt off the alternator and start it. See if it runs.
You can also spin the pulley with the belt off to see how it sounds
 
Can you pull the alt.take to auto parts store or ignition shop have it tested.Good greased bearing roll smooth but not free so if you remove the belt and give it a spin and it turns for ever then its time to replace the bearing. With the heat bearings dry out before they fail plus brushes don't last forever.Like said before check all electrical connections and battery health.
 
I can see where a bad alternator can cause problems with running, but having it trip the breaker is something else altogether.
Breakers can trip if they're bad, but most often they trip if there is a short in the circuit (s0mething grounding out or drawing too much power and overheating the wire) that they are on. That's what they are supposed to do.
As I indicated in my earlier post: I've had breakers go bad, but the symptoms were usually that they didn't supply any power to the circuit. But, if the pole switch were loose or worn, it could possibly trip. Start by eliminating that by either swapping the breakers to see if the problem moves over, or just get a new 10 amp breaker and give it a try. Even if the breaker isn't the problem, having an extra 10 amp breaker in your toolbox wouldn't be the worst thing in the world.
If you still have the problem with the new breaker, then start looking for a short, or swap out the alternator from the other motor.
 
Ok after some fussing and cussing I pulled the breaker and replaced it with a new one. That was the problem, it had gotten weak and is a 30 second delay breaker. So 30 seconds after the engine started or had turned over it would kick off. The alternator belt was lose and once I had tightened it up that to was fixed. So as of this writing things seem to be working again.

I will be putting 2 10amp breakers in the tool box this week
 
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