Starter not cranking - anyone know what this wire is?

[dad_n_Seattle]

Hi Forums,

I was doing some maintenance (oil changes, etc.) on my old Volvo Penta 2001 diesel (just bought boat) when my engine would not start - the starter would not crank. It had cranked before, but it took a long time to get the engine started. Looking around, I found this wire hanging around loose behind the alternator, near the starter. Just wondering if anyone with Volvo Penta 2000 series experience knows what this wire is?

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Is there an easy way to determine if your starter is dead vs. some other electrical issue? Batteries are fine as far as I can tell.

Thanks!

[Wotname]

I would look closely at the starter motor wires. In essence, the solenoid which is mounted on the starter motor should have one big wire going to the battery and one small wire going to the start switch. There is also a very short big wire going directly into the starter motor.

If the small one has fallen (or broken) off, the starter motor will not crank.

If the small wire is absent, see if this mystery wire will reach the starter motor.

[sy_gilana]

It looks like there is a broken off tab stuck inside the insulator, BUT it looks like the start wire (Usually White) is connected to the solenoid. Look for a broken off male spade connector.

[betwys1]

Originally Posted by dad_n_Seattle

Hi Forums,

I was doing some maintenance (oil changes, etc.) on my old Volvo Penta 2001 diesel (just bought boat) when my engine would not start - the starter would not crank. It had cranked before, but it took a long time to get the engine started. Looking around, I found this wire hanging around loose behind the alternator, near the starter.

Is there an easy way to determine if your starter is dead vs. some other electrical issue? Batteries are fine as far as I can tell.

Thanks!

There are a minimum of two wires going to a starter - if the ground return is carried through the engine casting - the engine needs a ground braid to the battery. One is thin, and one is fat. The fat one may be permanently connected to the battery live terminal. The thin one is activated when you push a start button, or turn a key to the start position.
Some people keep a multimeter. If you have one, you may check the thick terminal carries battery voltage - 12, 24 v whatever.
The THIN wire leads to a solenoid (an electromagnet) which does two things: 1) it slides a bendix gear into contact with a flywheel pinion.
2) It closes a giant contactor to handle the several hundred amperes needed by the starter, which when the main engine catches, spins the bendix gear back out of the way of the flywheel pinion.
If you are determined NOT to buy a meter, you may wish to rig a flexible wire cable to both sides of a battery voltage incandescent lamp. The loose ends of the wire are fitted with croc clips or probes. One is clipped to the battery return terminal, and the other lead is used to probe both the thick wire and thin wire in turn. Test the lamp by connecting directly to the battery.
If you have had trouble starting, and have NOT rested the starter every ten seconds, you may have burned the starter motor. When battery voltage is applied to the solenoid, it gives a noticeable thunk while it shifts the Bendix.
Two possibilities: No clunk? Solenoid failed or solenoid wire disconnected. Clunk but no spin? starter failed (probably)
The starter can often be removed with two or three securing bolts, after the 2 or 3 or 4 wires have been disconnected.
Dad n Seattle, you are now fully qualified to trouble shoot, and repair or replace the starter, as necessary. Don't wear a wedding ring while trouble shooting - it may get red-hot before you pull it off your finger.

Brian W

[Dsanduril]

You can grab a PDF of the workshop manual. Pages 26 and 27 have the wiring diagram. On page 27, item #6 is a little fuse block. If you have this version all of the control power goes through that fuse block, and they can and do die. There are five (IIRC) fuses in the block, one is in use, the others are spares, you move the wire over one slot when one blows.

If you have that version, the fuse block is clear plastic, and is mounted with a single screw right on top of the engine. Very easy to access (someone was thinking when they did that). The version on page 26 also has a fuse block shown, but I'm not familiar with that version so don't know if it was identical. The deluxe version fuse block can be seen in the photo on page 2 "Components Guide", it is above the alternator between the callouts for #3 and #4.

[dfelsent]

And!!! When you are using tools near those starter wires (other than meters or bulbs) turn off the switch to the starter battery!
If you have no switch disconnect the negative of the battery at the battery.
The wedding ring may burn your finger terribly, but the red hot tools may burn your boat to the waterline.
Disconnect, then no danger from that.

[DougR]

Disregarding for a moment this wire that is hanging loose, let’s look at the starter wiring.....

As stated earlier, there is a heavy battery cable coming to the starter solenoid from the battery switch, and it is bolted to the 8mm terminal on the back of the solenoid. Then there is a starter control wire that is yellow/ red that is also connected to the starter solenoid. This yellow/ red wire originates at a control relay that is mounted under the sheet metal cover on the top of the engine where the wiring harness connects. When you turn the key or press the start button you send current to this control relay which energizes and it sends current down the red/ yellow wire to the starter solenoid. All of this is easily trouble shot with a volt meter or even a simple trouble light.

In most cases of the 2001, the starter motor grounds thru the motor case directly to the engine block, but in a few late model saildrive models the engine block was electrically isolated and a grounding relay was used to ground the starter motor. You can tell if you have one of these by the large grounding relay adjacent to the starter motor. If so, this relay needs to be functioning as well for the starter to work.

As far as the mystery hanging wire, it probably came off the alternator, but might be the red/yellow which goes to the starter. I don’t remember if the starter is a push on wire, which this one is, or a bolt on eye. Scrape the green paint off the wire and see what color it is.....

[dad_n_Seattle]

Thanks for all the tips guys. I guess I'll have to start unbolting a bunch of crap to dig my way back to the starter to get clearance to see what's really going on! Thanks for the safety tips - Being new to marine engines, I appreciate any/all safety reminders!

[Wotname]

Originally Posted by dad_n_Seattle

Thanks for all the tips guys. I guess I'll have to start unbolting a bunch of crap to dig my way back to the starter to get clearance to see what's really going on! Thanks for the safety tips - Being new to marine engines, I appreciate any/all safety reminders!

Don't you love the lack of access in the engine space

Probably the first thing is to confirm if there is a broken piece of male spade connector in the mystery wire as identified by sy-gilana. If so, you need to look for corresponding end. BTW, sharp eyes there sy-gilana.

Originally Posted by sy_gilana

It looks like there is a broken off tab stuck inside the insulator, BUT it looks like the start wire (Usually White) is connected to the solenoid. Look for a broken off male spade connector.

[Greg Mason]

A headlamp and extended mirror can save a lot of disassembling.

[Wotname]

^^ As can a smartphone camera.

[esarratt]

Originally Posted by Greg Mason

A headlamp and extended mirror can save a lot of disassembling.

Yep!

You can also pickup 12"x12" acrylic sheet mirrors off Amazon for $12.99. They won't shatter like a glass mirror.

You can get cheap, lighted, flexible cameras that plug into the USB port on a laptop for just a few bucks online.

The manual for the engine has been helpful (I have a Volvo).

The parts diagrams you can find online for free from various Volvo dealers has also been useful at understanding how stuff goes together. Just search.

Originally Posted by dad_n_Seattle

Thanks for all the tips guys. I guess I'll have to start unbolting a bunch of crap to dig my way back to the starter to get clearance to see what's really going on! Thanks for the safety tips - Being new to marine engines, I appreciate any/all safety reminders!

Nigel Calder's two books are excellent:
Marine Diesel Engines
Boatowner's Mechanical and Electrical Manual