Unimog starter motor

[TopCut]

Hello, My U1600 unimog is not starting as it should, I feel it is due to the starter motor as when I turn the key the starter motor spins but does not always engage and with this cold weather it is not even worth trying to turn the key.

I just wanted to know if anyone had any ideas as to what could be wrong and if I put a new starter motor on would this fix it.

Any help would be great.

Ross

[skyhuck]

If the starter is not engaging sometimes change it quick!!!

 

Or you could end up knackering the flywheel, as when the starter does not engage properly it can damage the teeth. Unfortunately with 6 cylinder engines the flywheel stops in only a few different places each time, so those parts of the flywheel can soon be damaged.

[Mike Hill]

Mogs to my knowledge use a standard Merc Starter.You may well turn one up at a local Truck dealer.

[treequip]

Hello, My U1600 unimog is not starting as it should, I feel it is due to the starter motor as when I turn the key the starter motor spins but does not always engage and with this cold weather it is not even worth trying to turn the key.

I just wanted to know if anyone had any ideas as to what could be wrong and if I put a new starter motor on would this fix it.

Any help would be great.

Ross

 

Find yourself a decent auto electrician and get the old unit overhauled or exchanged.

[PeteB]

Spins but does not engage?

 

Hmm, sounds like the bendix is jammed in and does not fly out to engage the teeth on the flywheel. Take it off and check it over on the bench - it might be stock through mud/clutch plate dust/rust. Clean it, make sure it is free and then refit.

 

As previously stated, if there is a lot of mechanical graunching noises as it turns over then stop, it is eating your flywheel which can be a tad expensive!. Does anyone know if the ring can be removed or is a solid flywheel?

[skyhuck]

Spins but does not engage?

 

Hmm, sounds like the bendix is jammed in and does not fly out to engage the teeth on the flywheel. Take it off and check it over on the bench - it might be stock through mud/clutch plate dust/rust. Clean it, make sure it is free and then refit.

 

As previously stated, if there is a lot of mechanical graunching noises as it turns over then stop, it is eating your flywheel which can be a tad expensive!. Does anyone know if the ring can be removed or is a solid flywheel?

 

Solid I think mate, but its the cost of the labour (gear box out) thats the killer, IME.

Edited December 30, 2010 by skyhuck

[33bk]

as said be for find a good auto electrician get it fix up and looking sharp and it should only cost a crate of beer !

[John Russell]

Spins but does not engage?

 

Hmm, sounds like the bendix is jammed in and does not fly out to engage the teeth on the flywheel. Take it off and check it over on the bench - it might be stock through mud/clutch plate dust/rust. Clean it, make sure it is free and then refit.

 

As previously stated, if there is a lot of mechanical graunching noises as it turns over then stop, it is eating your flywheel which can be a tad expensive!. Does anyone know if the ring can be removed or is a solid flywheel?

 

I agree. Most starter motors are held on with just two bolts, so before getting in an auto-electrician, whip it off and check the bendix. It's a simple job anyone with a spanner can do. If you remove the power cable, disconnect the battery first as it will probably be live and you'll melt the spanner if it touches anything.

 

When you have the starter on the bench the bendix should twist up the helical thread very freely and then return to the disengaged position under the pressure of the spring, without sticking. Clean the bendix with a wire brush. You could also clean it with a little petrol so that it loosens any dust but then it all evaporates away without leaving an oily residue. Make sure you only dip the bendix in petrol -- not the whole starter!

 

Only thing I would add to the above is don't be tempted to oil the bendix once cleaned -- it's likely to stick more after a few days. You can use graphite powder but that's starting to get a bit technical.

 

If the teeth are badly chewed then you'll need to replace it. Some of the larger auto-electrical places will rebuild starters: cheaper than a new unit.

 

All the above won't take more than half an hour assuming the starter is easy to get to (sorry, don't know the details of Unimogs). if it still doesn't work after it's all back together then it's time to call in an expert.

[john the log]

exchange starter,about £160.tip-if your mog has a front pto,its a lot easier if you take it off.i found out the hard way.

[b101uk]

FYI: OM352 & OM366 flywheels have sweated on ring-gear.

 

With regards to starter motors a low voltage in the starting battery/s can cause the bendix pinion from flying out and engaging just resulting in the starter motor freely spinning then it flying out as soon as the ignition key is released as the armature slows causing a little “bang” as it engages and stops.

 

Other than that the phosphor bronze bearing can go on the carrier shaft for the bendix pinion causing misalignment of the pinion/ring-gear and the extra leverage imposed on the carrier shaft/armature takes out the armature end bearing the other side of the bendix causing repeated non starting (starter motor free wheeling) then eventually the misalignment stops the armature from turning.

 

Either way a rebuild of your starter with new bearings (3) new bendix, brushes, solenoid should be not more than ~£85 + VAT.

 

Really you could do with testing your battery/s (both for voltage and discharge capacity [A]) and earth/electrical connections for the starter.