Any thoughts on laboured starting

[Chris]

Chaps. Having some starting issues. I know that off roading the 80 usually leads to either the starter filling with crud or the alternator. Now before all the suggestions come in let's start from the basis that I am not a total donkey.
Yes there is fuel in it. No the fuel filter isn't blocked, not it hasn't been filled with petrol etc etc.

Here's what I can tell you. When you turn the key normally it starts on a touch. Recently had a couple of episodes where it didn't catch first time, but another go and it went. Then at Lincomb this weekend I didn't think it was going to start at all. it sounds just like flat batteries. Whuur whuuuuur whuuuuuuuuuuur then Whiiiir, brooom broom. The batteries are 2 years old. Topped up, reading well on hydrometer, standing charge good, fine with headlights on. Connections clean and bright. Starter came off tonight and the solenoid was hideous inside. Again. Like something from the sea bed. All clean and back together. Really thought this would sort it. But no, Whuuuur. It's firing up and running lovely - despite driving home from Lincomb with a blocked rad. Some of those hills got it pretty toasty.

Alternator newish and 120 amp kicking out top voltage. It sounds like there is massive load on the starter like it's trying to start a jumbo jet in gear. Could it be the gears inside the unit either needing a lube or a clean? Anyone had this before? It's pretty new itself since the last one caught fire. Doesn't sound likeit's kicking out properly either when it starts. I can't remember if the start pinion has a free wheel. Obviously when the start is flung out, it needs to lock in the starter ring. But IIRC you CAN spin the pinion backward like a bike wheel. Now on the bench tonight I couldn't turn the pinion at all.

To reiterate, this is nothing at all to do with fuel. It's not spinning over and not firing, it's struggling to turn over. Can't see it being the change over switch either. But not sure how to test that theory.

Anything I might have missed?

 

[clivehorridge]

Chris, no answers yet, just a question: are you running 24 volts or have you converted to a 12 volt starter? Dunno what to do with the answer yet either, but I need a box to think outside of...

Hey, great vids from Lincomb!

 

[PETE BELL]

can you try a spare starter to see if the result is the same -does your 80 start on 24v -it may be voltage drop ? last time I did the mud run at kirton both the starter and the alternator junked ,lucky I had both spare or it was home time

 

[Scott]

Try using a jump lead to earth the starter direct to the battery, and see if that makes any difference. Rules out poor earth connection between the engine, gearbox, chassis and batteries.

 

[Chris]

It's 24 volt start.

Could do Scott, but I already have extra earths on my motor to guard against this sort of thing. You heard it of course so you know first hand what I am facing. Classically sounds like duff batteries, other than as I say, they aren't old and check out OK. Stuck them on the smart charger in any case. But this was too sudden in my view to be batteries. Especially in Summer. I don't have a spare starter. I do really think that it is starter related though. Just sounds incredibly tight.

 

[Shayne]

http://www.offroad80s.com/viewtopic.php?f=14&t=11979

 

[Chris]

Thanks Shayne that's a pretty detailed thread. Good find.

I think that what I'll do first though is simply unbolt it, make sure it's earthed and turn the key with no load on it. Having done this before, I know it goes like a jet fighter. If it labours with no load or sounds stiff then the trouble is in there I think. I am sure that the pinion was free to rotate backwards. Just have to be really careful taking these to bits. There are a couple of thin wires that if you snap them, it's toast. All of the other connections look good and although old, this is a truck with only 77k miles on it!

 

[Shayne]

Maybe try blowing some compressed air in it you never know maybe a bit of grit got inside , could do no harm anyway .

 

[Scott]

....... I already have extra earths on my motor to guard against this sort of thing.

Between the motor and the chassis only? Or do you have additional earths between the battery and the chassis/body?

The jump lead test is a quick test to see if there are any restrictions in the earth circuit, and allows the starter to be tested under load. Handy for elimination purposes.

 

[Chris]

Not easily Shayne. It's a big thing but pretty sealed. This is what foxes me. Where does the shite get in? There isn't anywhere to blow in. Yes the motor has a drain tube, but the gear housing is all enclosed. Remember this is a 24 volt gear driven starter. I don't think a bit of grit would stop it. I wonder if it may be a bearing or something that's gone solid. The 80 starts so easily that frankly the starter motor barely gets a turn. As mine isn't a daily drive, gets off road then left for a fortnight, it's easy to see how the wet gets in there. I shall have another look tomorrow night. I think I might have a couple of stater bodies lying around so if necessary I might just be able to swap the electrical bits over. I'll look at some of those wiring suggestions too at the weekend when I have some help.

 

[Chris]

Sorry Scott wasn't suggesting I wasn't going to try that. Just pointing out that I have engine to battery extra earths in place.

Chris

 

[Towpack]

Chris,

Are you sure the changeover relay is actually operating? If not, the starter will only be getting 12v. Half the voltage means half the current and half the torque which would probably give symptoms similar to what you have.

 

[Jon Wildsmith]

Have you checked the voltage the starter is getting? If something was up with the changeover solenoid it would only be getting 12v.

 

[Chris]

No Phil, I am not. That's why I mentioned it. I'm not sure how to check that - until Jon just reminded me. Doh.

I need another pair of hands and daylight for that. But I shall check it out tomorrow. As long as it's not slinging it down like it was when I took the motor off. Which was worth doing btw to clean the solenoid out.

If it's not working then credit to the one battery for actually starting it!

 

[Jon Wildsmith]

In theory the starter relay won't power the start solenoid unless there is 24v at the starter terminal on the change over solenoid but it's still worth checking just in case something strange is happening.

 

[Chris]

Out tomorrow so will have to wait until I get a chance now. Got a pile of jobs to do on the old beast now. Never ending. Can't think why.

 

[AndycruiserguyLomas]

Chris I have a spare starter if you want to pop over and use the ramp. pity I didn't know you had a problem as I brought my heavy discharge tester to Lincomb to test Andy Brierleys batteries.

Andy

 

[Chris]

Cheers Andy handy to know. Should be able to determine whether it's the starter without having to swap it. But if I am completely bamboozled, I know where to come.

Thanks.

 

[Gary820]

See a few issues at work with starters going slow, presents itself like a low battery but it's the starter itself, usual complaint is suddenly it's slow to start. The motor just stops producing a decent output torque. It's the big diesels that seem to be affected.
They're a conventional starter motor and we're never allowed to strip them to see what caused it but they just go wrong.

 

[clivehorridge]

My experience has been shorts in the windings, which gives a reduced magnet on the armature. This shows itself as a sluggish motor and of course very labored cranking of the engine when engaged. They're not always easy to find either, they're often buried deep into the windings near the spindle. Why they occur has always baffled me, the wire has a lacquer finish before it's wound and you'd expect the shorts to be close to the surface where it's least protected. Not always so. A voltmeter would show it though, if you test each winding separately.