Engine won't crank if recently cranked

[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?

[ScottRhodes13]

Since the problem seems to happen after you've already used the battery for a bit, I would suspect weak batteries. But check for a voltage drop first, it could be a combination of both. (Also, it's cheaper.)

[Bill O]

Could be a weak battery, but would suspect the starter motor or starter motor solenoid.
Do you have an alternator/starter rebuild shop near you? Since this is a new to you boat, would have the starter checked over since it is an important part of the motor.

What motor do you have in your WS?

[Bill Seal]

Since it clicks but the motor doesn't turn it's probably the high current contacts in the back of the solenoid. (The one that sits on the starter and engages the gear, not the high current relay that sits somewhere else).

[sharutika30]

It may be the main wire to the starter is corroded or the ground that should be bolted close to the starter. If the ground wire is not close, relocate it to one of the mounting bolts of the starter. Check for proper voltage drop but suspect from your story it is not batteries.

[stormalong]

A dirty or somewhat loose connection gets hot the first time you pass current through it. You have to give it a chance to cool and then it will work again.

Remove clean, inspect and reattach each connection making sure that the nuts are properly torqued.

[Mike Banks]

Get a starting battery that is nothing to do with anything else on the vessel.

[billgewater]

Suggestions above all good. However, if it is an ongoing problem I suggest the following.
a) monitor the voltage to chassis at the positive terminal on the solenoid. If the voltage reading is more than a volt or two less than 12 V when attempted firing up, it may well be the wiring from the starter switch to the solenoid.

Sometimes the problem is actually in the starter switch itself as it may normally be expected to pass 5 to 20 amps and the internal contacts give up the ghost after a few years. The starter switch internal contacts may also be temperature sensitive
so won't behave well if you have been using it for a while.

Try monitoring any voltage reading across that switch when trying to start the engine.
Again, if this is any more than a 1 or 2 volts reading then the switch could be the culprit. If the measured voltage matches the drop at the solenoid terminal then the wiring is probably not the problem. It's the switch.

b) purchase a 12 VDC 30 Amp relay and wire it up to provide power to the starter solenoid positive connection. Mount it as near as possible to the starter solenoid. The switching circuit from your starter switch operates the relay and as the relay internal switch only requires milliamps to operate then any poor wiring in this circuit becomes essentially irrelevant.



The installation of a relay right next to the starter solenoid is a fairly common occurrence. These relays are only a few dollars and use standard slide on wiring contacts. They also usually have a replaceable 30 A fuse built in. The larger 60 Amp relays are generally overkill and, usually have two bigger nonstandard connections and usually do not have an inbuilt fuse.
The common 30 A relays usually have the high switched current standard terminals at right angles and opposite to each other and the terminals that you run from the starter switch and the chassis earth are opposite each other and parallel, but check with the retailer.

The wiring from the positive engine terminal (usually right next to or even on the starter solenoid) through the relay then to the starter solenoid should be able to handle the required solenoid current. This current is usually between 10 and 20 amps depending on the size of the solenoid itself. For your engine it may well be considerably less.

If there is no discernible voltage across the starter switch or a drop at the solenoid then the problem sounds suspiciously like an unhappy starter motor or the solenoid internal contacts may be in need of some TLC.

My electrician mate tells me this problem is common because boats often have long wiring looms, which, along with salt air is a recipe for wire and switch corrosion etc.

Oh yes. These 30 A relays are often cheaper than a new starter switch - depending on your access to OEM parts that fit.

[Ken Z]

Check your negative battery lead. I replaced one that had 8” of solid corrosion that had decomposed a copper lead, it was 2 yrs. Old.

[deblen]

Use your set of jumper cables.
First-connect a jumper from +Battery terminal to + Starter solenoid terminal(the other end of the original +Bat cable)


If above doesn't cure problem-Repeat above from -Battery terminal to the engine end of the original -Bat cable(usually the engine block.


Cheers/Len

[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.

[Bill O]

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.

If it is the solenoid on the starter, once you have identified the starter it is fairly straight forward to replace the solenoid. If you go this route, try to get a better one that is also a rated for high temp.

[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.

[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.

[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.