5.7 starter problems

[Grant Ingle]

Here's what happened. Replaced the starter mid-season,then the boat filled up with water over the starter. Two wires had burned off the back of the starter itself and another on the separate solenoid 6" above it. Removed and cleaned the starter, then bench tested it. OK. Repaired the wires and installed the starter. It spins just fine but the bendix will not engage the flywheel at all. Tested for voltage at the terminal on the starter and found only 5-8 volts during cranking. Tested voltage at the solenoid above the starter (yellow wire) and still had the same voltage (@7). Shouldn't this be 12 volts?

 

[Trent]

Re: 5.7 starter problems

9 volts is min. cranking voltage. Sounds like you need to check your connections or saltwater has "wicked" up your cables and corrosion has taken place. This resistance will cause lower cranking voltages. Clean connections first before replacing cables. Also do you have a voltage drop across the solinoid while cranking?? If so replace the solinoid.

 

[Grant Ingle]

Re: 5.7 starter problems

Removed starter again. Everything inside seems to be intact. This is a high torque starter(small motor). Bench tested again and noticed that a small amount of voltage is being delivered to the starter motor itself when I ground the frame and apply 12 volts (jump pack) to the small terminal on the solenoid. This is only supposed to activate the electromagnet to engage the bendix with the flywheel, right? Initially, the starter turned slowly then picked up right away and never did it again. Could probably attribute that to moisture within the starter but I could be wrong.

 

[Mike M2]

Re: 5.7 starter problems

The sylinoid has 2 functions. One is to engage the bendix to the flywheel, the other is to supply power to the starter. It's like a big relay, the small wire being the switch. It applies what ever voltage you have at the big terminal(battert) to the terminal entering the starter. Whatever voltage you have at the input terminal is what you should have on the output, privided the relay is engaged. If there is considerably less voltage at the Battery terminal than the battery itself, replace the cable. If the voltage entering the sylinoid is fine, but weak entering the starter(when engaged) replace the sylinoid. Someting else worth checking, The ground cable between the battery and the motor. Just as important! Use an ohm meter, should be little resistance from one to the other. A set of good jumper cables can come in handy to bypass cables if not sure. Bench testing sometimes won't help with no load on the starter. The sylinoid usually will always work that way. Try it on the boat.