Ignition problem?

[sub2010ss]

Here's a strange one. Just got my new motor in. I have been working on little projects and feel I'm almost ready to put her in the water when I go to start her at home on the muffs and it fires, dies, and nothing on the ignition at all. So I start trouble shooting. I spent maybe 5 minutes inside looking at the wiring diagram. Come back outside and give it one more shot before digging in and she fires right up? Any ideas?

 

[wrench 3]

If by "nothing on the ignition" you mean no starter, gauges or accessories. It sounds like you lost the battery feed to the ignition switch. Start checking connections where you were working. At the engine. The terminals at the battery shouldn't kill the engine if the alternator was working, so go to the battery terminal at the starter, the circuit breaker on the engine and the main harness connecter. Check for loose connections, wires partially pulled out of the terminals and damaged wiring. If that's OK then go forward and check the same at the circuit breaker/fuse and the ignition switch. If all that is OK, flex all the wiring harness by hand with the engine running and see if you can make it quit. If everything is still OK, you are going to have to wait till it quits and won't restart.

 

[sub2010ss]

I really hate wiring problems. All good advice as I really don't want to end up dead in the water.

 

[wrench 3]

Good luck.

 

[sub2010ss]

Got her all taken care of. Cleaned the battery terminals and she works fine now.

 

[Silvertip]

You just learned that when weird electrical things happen -- remove, thoroughly clean and reassemble (tightly) the battery cables and make sure the battery is fully charged, and capable of actually "holding" a charge. And remember that each battery cable has two ends. Doing one end does no good if it is the other end that is loose, corroded or otherwise defective.

 

[sub2010ss]

Exactly. I'm still dealing with some starting problems. Kind of a hesitation or weak battery sound to it. Still searching.

 

[wrench 3]

The boat manufactures quite often use some pretty poor quality battery cables. The cable itself can loose contact with the cable ends. You have to go along the system and check for voltage drop while someone cranks the engine.

 

[sub2010ss]

These cables look as if they have been replaced. They the pos are a transparent red and look really good.

 

[wrench 3]

The only transparent cables I've seen are for the supply on high output stereo amps. Maybe they make starter cables like that, but I haven't seen them.
I'm wondering if they're too light for the job. I'd still check for voltage drop.

 

[sub2010ss]

Ill check that for sure, what kind of drop should I see from battery to starter? These cables are definitely thicker than stereo power cables.

 

[Bondo]

what kind of drop should I see from battery to starter?

Ayuh,...... ZerO,....

 

[sub2010ss]

Ok, I took a ton of measurements and definitely didn't get zero. I realize in a perfect world there would be no loss but some should be expected? Here is what I got:

1.0 drop batt pos to starter pos
0.4 drop batt pos to battery selector switch
0.2 drop across selector switch
0.6 drop from switch output to batt pos
11.2 drop across battery pos and neg
9.3 drop pos of starter to starter case
0.8 drop neg batt to starter body
0.4 drop neg batt to block stud

 

[wrench 3]

Specs are maximum .5V drop in either positive or negative side of the system. .2 is acceptable for a solenoid, so would probably be OK for a selector switch. The .4 drop across the engine block jumps out at me. It should be really close to zero. Maybe paint or corrosion? The cables all look excessive.

 

[sub2010ss]

That's exactly what I thought. But the numbers don't scream any one particular failure. So I ripped it all down again. Took some 40 grit sand paper to every connection I could find. I'll have to check the voltage drop tomorrow but the starter is definitely working much better!

 

[Fed]

Different motor but I traced my tiny cranking hesitation down to a slipping bendix clutch.

The slip was minimal but just enough to make it not feel quite right at the start point but once the motor was cranking over it cranked very fast. Best I could do to prove the point was to mark the bendix to the nut as you would a prop hub.

 

[sub2010ss]

Replaced the starter last night as well. So with the combination of cleaning everything and the new starter she fires up better than expected! Thanks all!