How much voltage drop at Starter while cranking?

[joe_db]

If you really want to find the issue, connect one lead of your voltmeter to the coil + and the other lead to the battery + and crank the engine. The reading will be the voltage drop. Ideally it should be 0. If it is much higher than say 0.5 volts, you might want to work your way upstream and see where the voltage drop is coming from.

[hanleyclifford]

Hot wiring from S terminal on the solenoid is the just about the same as the "R whimp"; just do the whimp and we can both argue with Bro Neil.

[ndutton]

just do the whimp and we can both argue with Bro Neil.

No argument. If a work-around of the real problem is a suitable solution, go for it.

[67c&ccorv]

+1 with Neil on that.

[hanleyclifford]

No argument. If a work-around of the real problem is a suitable solution, go for it.

The "real" solution is probably a major re-wire of the electrical system; meanwhile I think Jack just wants to use the boat.

[ndutton]

The "real" solution is probably a major re-wire of the electrical system; meanwhile I think Jack just wants to use the boat.

. . . and the real problem will persist, perhaps even degrade. I've never seen one improve on its own. It's been going on a while too. This thread alone is six months old and the problem existed before that.

In time it will finally degrade to a point that . . . . aw, never mind.

[JackConnick]

R Terminal

Ok, as I said I narrowed it down to:

Hot wired: starts fine. No hot wire, a lot of cranking.

As before; new batteries, coil, plugs. I have magnetic ignition. Rewired "purple" wire with about 7' of #14. Battery wires to and from were replaced a while back and all are in good shape and inspected. I get a good strong spark from the coil.

The fact that the boat starts fine while hotwired eliminates them. I did notice quite a bit of voltage drop-off while cranking - (starter??). Late model engine.

I looked at the solenoid yesterday and it's all late-model, but other than the "S" term with the white wire, and the larger Battery term, there was another term, sort of in-between in size that had some sort of rubber piece on it. Hard to see, exactly as I was using a mirror, access is poor. I'm thinking this is an external ground to the starter? But I didn't think the later models had those. I'm a little confused that there is an "R" terminal...

...and sure, I want to fix it right...

So I think what I'm down to is that the ignition goes through the instrument panel, jumps from gauge to gauge with #12 wire with the white wire on the first one (or last one). I think I should replace the white wire, and maybe also run a jumper around the gauges, as well as leaving them wired.

I mean there's not much left, and with the hot-wire acid test that sort of narrows it down, right??

Jack

[JOHN COOKSON]

Ok, as I said I narrowed it down to:
Hot wired: starts fine. No hot wire, a lot of cranking.
As before; new batteries, coil, plugs. I have magnetic ignition. Rewired "purple" wire with about 7' of #14. Battery wires to and from were replaced a while back and all are in good shape and inspected. I get a good strong spark from the coil.
The fact that the boat starts fine while hotwired eliminates them. I did notice quite a bit of voltage drop-off while cranking - (starter??). Late model engine.
I looked at the solenoid yesterday and it's all late-model, but other than the "S" term with the white wire, and the larger Battery term, there was another term, sort of in-between in size that had some sort of rubber piece on it. Hard to see, exactly as I was using a mirror, access is poor. I'm thinking this is an external ground to the starter? But I didn't think the later models had those. I'm a little confused that there is an "R" terminal...
...and sure, I want to fix it right...
So I think what I'm down to is that the ignition goes through the instrument panel, jumps from gauge to gauge with #12 wire with the white wire on the first one (or last one). I think I should replace the white wire, and maybe also run a jumper around the gauges, as well as leaving them wired.
I mean there's not much left, and with the hot-wire acid test that sort of narrows it down, right??
Jack

I got so sick and tired of this kind of monkey business on my boat that I finally did a global rewiring of the engine, gauges, ignition, and everything else associated. All end connectors are crimped, soldered, and heat shrunk. Got rid of all the trailer type plugs. It's one soild wire from A->B except for the in line fuses I added.
Problem(s) solved.

TRUE GRIT

[JonnyQuest]

I got so sick and tired of this kind of monkey business on my boat that I finally did a global rewiring of the engine, gauges, ignition, and everything else associated. All end connectors are crimped, soldered, and heat shrunk. Got rid of all the trailer type plugs. It's one soild wire from A->B except for the in line fuses I added.
Problem(s) solved.

TRUE GRIT

Good for you John; I'm still Monkeying around with mine
Started my A4 up for the first time this spring and measured 13.x volts at battery-- gotta recheck my alternator wiring and see what's amiss. --Normally measures 14.x on mine.

[JackConnick]

More discoussion with Don

He seems to think if it's running fine after starting that the starter is drawing too many amps while cranking and is making a weak circuit bad. Sound like I need to pull and check the starter... groan.

Jack

[JonnyQuest]

With all the checks you have done so far and replacing with new batteries, checking the starter sounds reasonable. I pulled mine and took it to a local shop for bench testing last fall. My problem was bad batteries, which you have eliminated from your list of suspects.

While the starter was off I gave the exposed area of the engine behind the starter a good knock down with a wire brush and degreaser and touched up the paint. Good opportunity.

[ndutton]

Ok, as I said I narrowed it down to:
Hot wired: starts fine. No hot wire, a lot of cranking.

Please describe exactly what you mean by "hot wired." Does it mean:

1. #14 wire from a battery post to the coil + terminal?

or

2. Jumper from the battery post to the solenoid "S" terminal to activate starter?

[JackConnick]

Neil;

Jumped from large battery connection of solenoid to + of coil. So essentially from battery to coil.

Jack

[ndutton]

I don't understand the logic

Hot wired: starts fine. No hot wire, a lot of cranking.

The only change with the hot wire in place is bypassing the ignition circuitry to and from the ignition switch and the switch itself. Same starter, same solenoid, same starter wiring, same starter load, cranks fine with or without the hot wire.

So the starter/solenoid/starter wiring is now suspect? I don't see why, it's working fine and the test with the hot wire proves it.

Based solely on the successful hot wire test I'd replace the ignition wiring, the supply from the battery to the ignition switch (red), the load from the switch to the coil + (purple) and the switch itself. Make it as first class as you can. Red supply should be #10 minimum, I'd bump the purple load up to #12, tinned wire all around with terminals crimped, soldered and shrink tubed. The switch should be marine grade, if a combination start and ignition keyswitch, 30 amp rating would be nice.

[JOHN COOKSON]

If you are resorting to jumper wires it's time to rewire. Here's why: If the wiring is in such poor shape that you need a jumper wire across part of it there is a very good probability that some other part of the wiring will go out soon. Usually at the most inopportune time............Been There. Done it. Didn't like it.

If you need coaching with soldering technique let us know.

TRUE GRIT