Slow Cranking-Battery? Fiat Heston 605C

Paul007

Member
My old crawler has always taken a lot of battery to turn over but last year with 3 car batteries in parallel it started pretty well cold and I got a lot of use out of it.

Tried to fire it up yesterday after winter and was unable to get it to turn over more than 2-3 revolutions. I had 3 car batteries on it again, each one able to start a car with ease, two sets of heavy cables bolted to the starter and engine and my truck running with jumper cables, every battery showing 14+ volts.

I would love to pull the starter and have it tested but the roll cage is in the way. I was able to pull the end cover off and remove one brush. Everything looks to be in great shape. The commutator was black but a quick wash with brake clean and it was back to nice smooth copper.

I tried jumping straight from the battery pole on the solenoid to the starter pole with a wrench. Just about welded it on but still cranks the same. If I remove the cable from the battery pole and touch it direct to the starter pole it runs the starter motor without engaging the bendix and it runs nice, smooth and fast. Also with the cover off I was able to turn the armature by pushing it with a stick, turns freely and smooth.

Apparently there are clip on amp meters that can tell the current draw while cranking, maybe that would help isolate the trouble.

The factory battery for this thing is huge - 20 x 8.5 x 9.5" and weights 120 lbs. and rated at 143 20 hour rate (what does that mean in CCAs?). Would a new group 31 950 cca battery suffice? It's a 4 cylinder diesel. The starter is 4hp.

Could I possibly be not supplying enough battery?
 
Start off with the battery is it good?,then check the cables,is the ground cable going directly to the start motor or to the frame,if it going to the frame check the ground cable/strap connection from the battery to the frame and again from the frame to the starter,once you have established that the battery and cables are in good condition you can test the voltage,use a volt meter to test the voltage while cranking,connect the positive of the volt to the main cable at the starter motor,connect the other lead to the ground on the starter,note the reading,with an eye on the meter crank the engine over,note the reading,if the reading drops a lot either the battery or the leads/connections are faulty,if it only drops a little its would say the battery leads/connections ok,now connect the positive lead of the meter to the other terminal of the solenoid,crank the engine over and note the reading,if it is not near the same as the other reading the solenoid is not making good contact and therefore the starter is not getting enough power and will give flat battery effect,if the reading is near the same you will have to have the starter off and to a shop that has a proper load testing equipment,a lot of starter repairs shops do no more than you can do yourself just motoring the starter without load is not a true test,lots of guys on here have changed their machines over to 24 volt to solve the starting in cold ares.
AJ
 
Thanks AJ, I will try the voltage tests. I might also pull the fuel injectors to relieve compression and see if that helps it turn over.

With the 24v conversion are the starters being converted? I had a 6v 1954 truck that I used to start with a 12v battery once in awhile, that really woke it up.
 
I would not disturb the injectors unless the engine is not running properly,the starter will turn faster without the injectors but you will be back to square one when you put them back and you will still have to take the starter off,when people convert to 24V they usually leave the starter and should it fail then replace it with a 24V one,the starters will last for ages as the engine starts so fast they don't have time to heat up like they do when slow cranking for ages like yours is doing now,try yours on 24V,disconnect the heavy wire from the alternator and insulate it, make sure everything is switched off and its out of gear,connect another battery in series to the one you got in ie remove the ground cable from the negative pole of the battery,use a jumper cable from that battery negative pole to the positive pole on the spare battery,connect the other jumper cable to the negative of the spare battery to the ground cable,hit start and see how it goes.
AJ
 
Got out there to try the voltage test today. With my truck running and jumpered to it I have over 14 volts at the tractor batteries. When I crank it over it drops down to 9-10 volts, both with the positive lead of the meter at the battery or at the terminal on the solenoid where the cable goes. I didn't think to check at the other solenoid post that goes into the starter. I did not try 24 volts yet, not knowing what the voltage test means. Will 24 volts with the same batteries give more cranking power than the same batteries hooked in parallel at 12v?
 
continued... I had the negative volt meter lead at the battery, didn't think to try it anywhere else.
 
You need to connect the volt meter ground to the starter motor directly,one of the mountings bolts or the like,then check the reading first on the battery cable which is the in terminal on the solenoid and then the out terminal and compare the two,the 24v hook up doubles the voltage and will spin the starter like you experience with your pickup when you use a 12v instead of 6,be careful with batteries esp after charging them as the give off a gas that can explode should there be a short,always have the caps off when charging so there will not be a build up.
AJ
 
When I read your reply again I see you have the jump leads on from the truck,I did not mean that you do the test that way,the voltage reading is coming from the truck alternator,do the test with with it's own battery only without the jump leads and report the readings.
AJ
 
i am ivor from uk and I used to work at tractor dealer but faulty starters were always sent off to be fixed but I remember a guy telling me who used to work on bomber serviceing during WW2 that he fixed a starter that had worn bush in end plate, this guy has passed on but he had a lot of experience with engines and vehicle electrics and transmissions .I hope this may be helpful
 
I tested at the starter terminal and mounting bolt, down into the 8v range while cranking, about a volt down from testing at the battery but it's hard to say exactly how much.

Then I tried 24v with only two big batteries. Started to crank faster but quickly died down to stall.

Last attempt, I went back to 12 volt with 4 batteries (in parallel) on separate cables, and with my truck jumpered and running it started! Whew, good to finally hear it purring again. I ran it for 15 minutes, shut it off, unhooked my truck jumpers and it again started on the 4 batteries, turning over nicely. I unhooked the two batteries that were not mounted, hopped in and pushed dirt around for half an hour. Shut it off, no restart on just the two batteries. But at least it ran!
 
Are you sure the machines own battery is good,if there is a bad cell in it it will drain the power from the other batteries,have the battery tested with a load tester,by what you say that when you had it on 24V that it would not crank one of the batteries is bad.
AJ
 

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