Battery seems weak

I have a 1976 Evinrude 135. It has new battery and starter, but it acts like the battery is weak and the battery cables get real hot when you try to start. Any ideas?

Re: Battery seems weak

If the cable from the solenoid to the starter is grounding anywhere it will flow great amouonts of current to that short and little to the starter.

Same if there is an internal short within the solenoid.

Test with an Ohms meter, disconnect the + battery cable at the battery.
Also disconnect the cable from the starter motor.

Ohms test the cable to the motor, if there is ANY reading at all then there is a short in that cable OR the solenoid.

If no reading then look at the cable to the motor to see if any heat/burn marks where it had been touching any metal.

Re: Battery seems weak

When there is resistance in a circuit, you can find it by touch (heat), or voltage drop. Faulty wiring and loose/dirty connections are the main culprits in a faulty ignition system. Starters and solenoids are often replaced for no reason. Take off all connections, and polish them until they shine, then re tighten. Dont simply look at them. Any wiring with nicks, cuts, abrasions should be replaced. If the wire "crunches" when you flex it, that is also a sure sign of corrosion. And as stated, if it is warm to the touch, there is resistance there.

If you would like to know how to physically test the voltage drop, see the following.

First set your DVM to the 20 Volt scale

Put your POS voltmeter lead on the battery POS terminal and the voltmeter NEG lead on the large incoming solenoid/battery terminal post and give her juice. If the meter reads more than .3 volts, the battery cable is bad, corroded or you have a faulty connection (loose).

Next, connect the POS lead to the incoming large solenoid post and the NEG lead to the outgoing large solenoid post while giving her juice. If the voltmeter reads greater than .2 volts, the solenoid is bad, corroded or has a faulty connection.

Next, connect the POS lead to the outgoing large solenoid post and the negative voltmeter lead to the starter positive post and give her juice. A reading of over .2 volts indicates faulty wiring between the solenoid and the starter.

Finally, connect the NEG lead to the NEG battery post and the POS lead to the engine block and crank the engine. A reading greater than .3 volts indicates a faulty negative cable, corrosion or a faulty connection.

Re: Battery seems weak

Thanks very much.

Re: Battery seems weak

The single most notorious cause of this common problem is the connection of the battery ground cable to the engine block.

The terminal on the end of the cable is copper, sometimes tin plated copper, and it is usually bolted to a steel part with a steel bolt and nut. Electrolytic corrosion is guaranteed over time and needn't be visible to create a low resistance in the connection.

That low resistance will prevent the starter circuit (and sometimes the PT&T circuit) from getting enough current to operate properly, but enough current to overheat the cables in the circuit while the operator keeps the power on.

This is the first thing to check, though other connections and the cables themselves sometimes cause the same symptoms.