Engine won't crank if recently cranked

[Cheechako]

First, make sure the cable that grounds on the engine block has clean contact. (also other cable ends but this is a common one) It can look fine but have 'wet or oily surfaces or wet corrosion' there.

[stormalong]

Originally Posted by warren5421

Sounds like a starter problem. Check that your contacts are clean on the solenoid. Remove the wires and clean the ends put back on if problem is still there remove the starter and have checked. The solenoid could be hanging up and after a few seconds it could be leting go and starting. You can replace the solenoid to see if that fixes the problem.

Point 1 of the OP's initial post says this is a problem when just using preheat, before a first try to crank.

This is definitely a voltage problem. Either a cable or battery.

The OP also says same problem on two different batteries.

That eliminates battery issue unless both batteries are weak.

Since the starter won't turn over after the preheat for 20 seconds that leads me to the conclusion that it is wiring, not the starter or solenoid.

[Cadence]

Originally Posted by fourlyons

I also would first suspect the high current contacts in the starter solenoid, the one mounted on the starter. A quick, easy test is to tap the solenoid with a hammer while trying to start the engine. The contacts get burnt over time and the hammer taps can reestablish contact temporarily. This won't fix the problem, only identify it.

Tapping it might also reseat worn down brushes. Why either would be time sensitive?

[donradcliffe]

Its time to isolate the problem. Here's where I would start, assuming your engine electrical system is not Lucas, the Prince of Darkness.

Measure the voltage between the heavy red wire on the starter and the starter ground when you try to start. If its more than 11 volts, the problem is in the starter or solenoid.

If more than 11 volts, also measure the voltage between the smaller red wire on the solenoid and ground. If it is less than 10volts, its a wiring problem to or from the panel. Also jump between the heavy wire terminal and the small red wire terminal on the solenoid. If the starter engages, the problem is not the starter/solenoid, and is wiring.

If more than 11 volts, measure between the starter battery terminals when starting--the lead posts themselves, not the wire ends. Since you have 6v batteries in series, the terminals in question are the ones that go to the boat ground and the boat load. If this is less than 10 volts, at least one starting battery is toast. Measure across each battery to find which one is more or less than 5 volts. If you have more than 10 volts total, measure between the positive terminal and the heavy starter wire when starting. A voltage of more than a volt tells you the problem is in the positive battery wiring/connections. Likewise measure between the starter case and the negative battery terminal. Measurements at every connection between the battery and the starter will isolate the problem.

If you have a Lucas starter, you need the post graduate course..

[Ballsnall]

Originally Posted by wiley 007

If your engine is below the waterline then you may have pumped water into the engine if engine has water it will not turn over.

It's Ok, the pumped water is to cool the engine due to the heat produced from the combustion process. If you remove the water the engine will still work but it might rattle and bang a bit and sometimes glow a nice red colour.

[Nord Sal]

I had a similar problem with pretty much the same behavior. The contacts in my starter solenoid were fried resulting in a poor connection. I believe trying to start it with weak batteries was the cause (low voltage > high current) of the contact's demise.

[fourlyons]

Originally Posted by Cadence

Tapping it might also reseat worn down brushes. Why either would be time sensitive?

Good question, I don't think they would be time sensitive. But then I don't think voltage drops at poor connections would be either. I'm not yet convinced the crank/no crank symptom is casually connected to the prior use of the glow plugs or prior cranking of the starter. How consistently does one follow the other? It might be coincidental.
My suggestion comes from many years experience as a professional mechanic using this quick test to eliminate a worn/old starter as the problem. The other suggestions to check for low voltage, weak batteries, etc. are also good suggestions.

[Uncle Bob]

Originally Posted by Lake-Effect

Based on the limited information given, I would first check every connection in the path from battery to starter. Measuring the voltage drop at various points while starting (takes two people, or a meter that will catch and hold a minimum reading) can help isolate a problem component or connection. Look for connections that are loose, or that show signs of heating.

In particular, measure at the starter solenoid when cranking. If the voltage is still reasonably high there... bad solenoid. If the voltage drops to nothing there when cranking, solenoid's ok and the problem is upstream.

But my money's still on a poor connection somewhere.

+1

Originally Posted by wiley 007

If your engine is below the waterline then you may have pumped water into the engine if engine has water it will not turn over. When trying to start any engine that is below the waterline you will have to turn Off the intake water to the engine and work on get it stated when it fire off STOP the engine open the water intake and restart. If you get water in engine you will have to remove the injectors and get the water out, don’t leave the engine with the water in it.

This is not the problem and if the poster had read the thread they would have noted this.

[Ryban]

Whoa, all really good advice to help me chase this down, thanks all!

I started to debug this from a voltage/contact perspective, but quickly got side tracked when I started trying to chase down wires, which turned into me tracing every wire in the charging circuit and building out a schematic.

I haven't done the proper point-to-point voltage drop checks yet, but one quick thing I did do though is turn on my LED cabin lights and tried cranking -- those definitely flicker out while cranking and voltage drops to something like 10V on my battery monitor.


Battery Isolators/combiners: I also wasn't able to isolate the banks, even after turning off shore power, cranking the engine to drop the voltage, and ensuring the battery selector switches (it's a 3 selector config) were such that the banks should have been isolated. There are two battery isolators in the circuit, one for the alternator, one for the AC charger. The solar has a manual bank selector instead of an isolator/combiner. My first thought is maybe one of the isolators has failed and the banks are permanently combined. The other possibility is that there's somehow a short somewhere on the positive side between the banks.

Batteries are old: Fortunately for me, the previous owner kept meticulous notes about all his purchases and work he had done on the boat. It looks like these 6V AGM batteries are from 2016, so they're nearly 7 years old, and I think it's time to replace them anyway. I think I'll also replace much of the wiring and re-organize it in the process since I'm not super pleased with how things are configured and I want to fix these gremlins before I ruin a set of brand new batteries.

[gpshephe]

Check your connections. Loosen all connections, apply silicone grease to all contacts including solenoid and starter. Tighten all connections. Should start at 12V, but wait for 12.50, then try. Worked for me.

On that note what's charging your battery, Dockside, Solar, Generator?

[Nibiruwayne]

Originally Posted by Ryban

I'm pretty sure this is a battery or weak connection issue, but wanted to get some feedback to help me debug this week.

My Vetus M4.14 will always start, but has a few concerning quirks:

1. If the engine hasn't been recently run, I'll use the glow plugs for 10-15 seconds, but have to wait an equal amount of time before I can start cranking the engine, or I'll just hear a click of the solenoid, but no motion from the starter motor.

2. If I have been cranking to say, bleed the fuel lines (self-bleeding), for a short duration, I need to wait a good 20-30 seconds before I can start cranking again, or again, I just get click of the solenoid.

I suspect this is because whatever voltage the starter motor is seeing, it's below some threshold and it's not getting the power it needs.

I have two battery banks, one made up of 4 x 6V batteries and the other 2 x 6V batteries. They can be isolated, but I've experienced these issues with both banks combined. I'm not sure if I've actually isolated them and troubleshooted, because even when they are isolated by the main switch, there is a switch in the charging circuit that will combine them when they're being charged (which has been most of these times).

It could also be corrosion in the wires or on the terminals, so I'll check and clean everything when I'm back on the boat. I'll also do some voltage drop checks to see if I can narrow it down.

If it's not any of those things though, where else should i look?

Does your starter require 12 volts or 6? If 12 then your batts are wired in series. Do you have standard 6 v or golf cart 6 v. ( wired in series or parallel?) In any case- you have double the terminals as opposed to a 12 v system- diuble the opportunity for corrosion which always reduces current . I would focus on the battery banks, the charge circuits and all battery cables ( internal- as well)

[team karst]

I had a fair mess with starting the last couple months offshore.
First, the glow plug relay slide on wire connectors got loose, and didnt respond well to tightening. And a week or two later, the starter relay acted up similarly. I had to wiggle the relays before starting, almost every time.
These are the little black cube automotive relays in wide use on cars.
Now home, i can really fix these.

[bharney]

I had similar problem on my yanmar 3hm35. caused by voltage drop in yanmar wiring, adding a second solenoid to operate the starter solenoid as "billgewater" describes solved the clicking problem. Also, if you are using deep cycle batteries for starting that can be problematic because the starting current load will likely cause voltage drop that causes the solenoid to drop out. A dedicated starting battery is a better option.

[rob d]

Hopefully you have it sorted out by now but the folks gave you some very good answers and not one off the wall answer or guess in the bunch.

Simple things first:
Start at the batteries and check the voltage.

Then inspect and clean every battery cable connection in the system starting with battery posts and ending with the connection to the solenoid or starter. That only takes a wrench or two, a wire brush and some sand paper plus some time. This means on all ground cables and connections too. 60% of the "won't start issues I have checked are bad ground issues. Again clean bare metal under all contacts.

As suggested earlier inspect the cables for corrosion. Capt. Jim's teak is gray, brass is green does not apply here, you do not want to see green on any of your copper wires or brass connections.

Then if you still have issues start checking the details. Did someone replace a cable With a smaller auto parts store 12V cable? Is anything else in the circuit suspect?

Then if things aren't working right you deal with the solenoid or starter it's self.

[Shaneesprit]

Originally Posted by Ryban

I'm pretty sure this is a battery or weak connection issue, but wanted to get some feedback to help me debug this week.

My Vetus M4.14 will always start, but has a few concerning quirks:

1. If the engine hasn't been recently run, I'll use the glow plugs for 10-15 seconds, but have to wait an equal amount of time before I can start cranking the engine, or I'll just hear a click of the solenoid, but no motion from the starter motor.

2. If I have been cranking to say, bleed the fuel lines (self-bleeding), for a short duration, I need to wait a good 20-30 seconds before I can start cranking again, or again, I just get click of the solenoid.

I suspect this is because whatever voltage the starter motor is seeing, it's below some threshold and it's not getting the power it needs.

I have two battery banks, one made up of 4 x 6V batteries and the other 2 x 6V batteries. They can be isolated, but I've experienced these issues with both banks combined. I'm not sure if I've actually isolated them and troubleshooted, because even when they are isolated by the main switch, there is a switch in the charging circuit that will combine them when they're being charged (which has been most of these times).

It could also be corrosion in the wires or on the terminals, so I'll check and clean everything when I'm back on the boat. I'll also do some voltage drop checks to see if I can narrow it down.

If it's not any of those things though, where else should i look?

Your batteries are not designed for the high current loading of a starter motor - probably don’t even have CCA rating on them? This could also cause damage to the solenoid contacts if the solenoid is reluctant to engage.

Batteries for house banks are intended for slow discharge, where as an engine battery is designed to release full power immediately, but for short durations

Also how close is the battery bank to the starter, ideally you will want to be 1 - 2 meters, after that you need to start considering increasing the the cable diameter, battery cables are specified on resistance of the length.