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post #1 of 3 Old 02-23-2019, 08:42 AM Thread Starter
Hemlock Case Guy
Join Date: Mar 2013
Location: Michigan
Posts: 281
446 Surprise Bad Wire

A guy had called me about an 1987 446 Onan engine a year or so ago, that the starter had gone bad on. He had the original starter rebuilt. He had called me to buy a starter and that is what I told him is by far the best route to take.

His eyesight is now bad enough that he cannot work on it anymore. So, it is now in my garage. He put it back together mostly. I told him to just go ahead and take the fan shroud off, That means more work to some. To me, it gets the job not only done right, but it allows you to do much-needed cleaning and inspection at the same time. He also repainted all his tins while they were off.

After connecting the fuel pump pulse line and actually screwing in one spark plug I was able to start testing. Yes, his eyesight is getting that bad. and he is 77. So, he gets a pass.

The solenoid was not getting a full click on every turn of the key. I had 12.5vdc at the battery and the orange wire to the ignition switch. I only had .9vdc at the solenoid tripwire. Replaced the ignition switch and now have 12.5vdc at the solenoid. Still not getting the starter to turn.

Replaced the solenoid as one post was bent, somehow. Now, I do get nice consistent clicks at the solenoid. Nothing at the starter.

Measured 12.5vdc at orange + feed wire to the ignition switch, same to the solenoid + on the key turn to start. Then I measured battery voltage at the post for the solenoid to starter wire and that passed. I next moved the probe to the starter post. At the starter post, I have less than 1vdc.

So, there you go. That is why you chase the voltage with a basic voltmeter. As I did this, it was not anything that hard. It was a basic understanding of the voltage has to move no different than water through a pipe. The problem is the original solenoid to starter wire is bad. Most likely at one of the crimps. For those of you that think checking is looking, this wire looked good. It tested as bad though.

Ignition switches are often bad and considered a wear item. It had the battery input terminal, the most common culprit, all rusty and it was loose on the peened pin of the switch. But, most the time if you have electrical problems, just replace the ignition switch.

Solenoids are less than $10 at most places. Again, just replace it if something is not right when you turn the key. The wire going bad from the solenoid to the starter is not normal. But, obviously, it
happens. I have never been a fan of these wires as they were barely the correct gauge, cheap stiff wire with crimped ends that are very marginal and cannot flow the current the cheap wire can flow.
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post #2 of 3 Old 02-24-2019, 02:06 PM
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Re: 446 Surprise Bad Wire

Yep, those cheap steel terminals often rust on the inside and the rust prevents good contact with the copper wires and 'almost right' factory crimps don't help at all.

I've seen some that when testing I'd probe the wire inside the terminal and get good voltage, but the terminal, not so much.
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post #3 of 3 Old 03-01-2019, 05:38 PM
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Location: Michigan
Posts: 2,549
Re: 446 Surprise Bad Wire

It's a good observation and nice restatement of the methodical chasing out of an electrical gremlin. Some are super obvious and others you've just got to go hunt for with a meter.

To add to the learning here we find a fair number of cases in which the static voltages will test OK, leaving you to think it's all good. But then try to put load in the wire (e.g. the starter cable) and it won't pass the necessary current. Bad crimps/joints and even broken copper strands internal to the wire.


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