Sluggish starter motor |
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oscar225
Senior Member Joined: 03 Nov 2018 Location: Devon Status: Offline Points: 204 |
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Posted: 21 Mar 2020 at 16:36 |
Hi in the process of finishing the complete rewire of my 67 V700, had a new loom from Greg Bender along with his relay upgrade also fitted an alternator conversion from Scramnler cycle. Brand new fully charged battery but when i attempt to turn it over it usually clicks and when it does catch is very slughish. I have bench tested the starter and all preforms as it should, i have cleaned the paint from the battery tray to ensure a good earth contact and even swapped the relays although all new without any joy, the only good thing is i have 12 weeks to try and resolve the problem as i am within the at risk group and in lock down, any ideas or suggestions would be welcome.
Thanks Chris
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Richard Hyatt
Senior Member Joined: 14 Oct 2019 Location: Dorset Status: Offline Points: 1097 |
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Always consider voltage drops.
Use a decent volunteer and put 1 clip on the battery earth negative lug and the other clip ontp the engine. When you crank it , you should preferably show 0volts indicating a good earth path. Any voltage shown will indicate a bad earth connection somewhere along that negative route. I've always used 0.5v as a max Do the same process along the positive path starting at the lead battery terminal and other clip on the big terminal on the starter, it is not unknown to lose volts across the solenoid itself built onto the starter. Again 0.5volts max As an AA man , the number of times I've diagnosed dirty corroded connections is amazing , crimps and spades can lose lots if filthy or corroded. The same trick can be applied to the charging side , but of course you've already checked the earth side out above.
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Brian UK
Moderator Group Joined: 13 May 2014 Location: Surrey Status: Offline Points: 17641 |
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Is this standard AA proceedure?
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Brian.
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Brian UK
Moderator Group Joined: 13 May 2014 Location: Surrey Status: Offline Points: 17641 |
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Are these the pre-engaged starters or the bendix type? Testing off load is not going to tell you much. There is a guide to testing a starter motor in the FAQ section. I would put a voltmeter across the battery terminals and check what the voltage drops to when you push the button. Then check the volts across the starter to earth in the same way when you press the button. They should be much the same. If the second reading is rather lower, then you have a bad connection somewhere. Just another way, and possibly simpler, to do the test Richard suggests.
Edited by Brian UK - 21 Mar 2020 at 17:51 |
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Brian.
Better 5 minutes late in this world than years early in the next. |
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Richard Hyatt
Senior Member Joined: 14 Oct 2019 Location: Dorset Status: Offline Points: 1097 |
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Certainly , we always taught in our technical training the principles and usage of volts drops.
I can vividly remember a member , whom i attended ,complaining of flat batteries every few days. Using this test, i fiscovered only 11 volts reaching the battery , but at the alternator red post , there was a good 14.2v. Using this test , end to end of the positive side, enabled me to discover that 14 v went into a crimp on the starter post but only 11 came out the same post on the lead to charge the battery . Bingo , dismantle , clean green corrosion , full volts.
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oscar225
Senior Member Joined: 03 Nov 2018 Location: Devon Status: Offline Points: 204 |
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Thanks for the replies will venture into the garage and do some more investigation tomorrow, only issue is my voltmeter is the older needle type rather than digital, but if its a big enough drop ishould see it OK.
Thanks again will keep updating, Chris
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Richard Hyatt
Senior Member Joined: 14 Oct 2019 Location: Dorset Status: Offline Points: 1097 |
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Needle or analogue meter is fine
Just disconnect the means of sparking though , to make the starters electrical paths 'work's During cranking. This'll give you enough time to look at the needle
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Brian UK
Moderator Group Joined: 13 May 2014 Location: Surrey Status: Offline Points: 17641 |
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Often an analogue meter can be better than a cheap digital. There is a considerable delay in the reading on cheap digital meters, enough to confuse anyway. But yes. pull the plug caps off so it won't start, gives you a bit more time to read the scale.
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Brian.
Better 5 minutes late in this world than years early in the next. |
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Brian UK
Moderator Group Joined: 13 May 2014 Location: Surrey Status: Offline Points: 17641 |
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It may be that you find no fault in the wiring, in which case you might find the brushes in the starter motor are worn, or the commutator itself.
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Brian.
Better 5 minutes late in this world than years early in the next. |
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Dave P.
Senior Member Joined: 12 Jan 2015 Location: Northants Status: Offline Points: 5573 |
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You could remove the heavy cable from the battery to the starter motor and with your meter check the cable alone for resistance end to end.
I had the same problem on my Laverda GTL as you have. The cable looked fine but when checked as above it registered a high resistance when it should have registered none,or very nearly none. It turned out that there was much corrosion between the copper conductor and the terminal lugs. Suspicion turned to the cable when it was noticed that after repeated attempts to start the engine the cable became quite hot. The corrosion was not visible until a terminal lug had been removed. Edited by Dave P. - 21 Mar 2020 at 23:03 |
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Amboman
Senior Member Joined: 05 Dec 2015 Location: Maryland, USA Status: Offline Points: 383 |
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It may be time to service the starter - disassemble, clean, inspect, grease and carefully reassemble.
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Charlie
'69 Ambassador,'71 Ambassador,'73 Eldorado,'75 Eldorado police,'76 Convert,'77 Morini 3 1/2 Strada,'81 Ducati 500SL Pantah http://www.AntietamClassicCycle.com |
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oscar225
Senior Member Joined: 03 Nov 2018 Location: Devon Status: Offline Points: 204 |
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Thanks for all the input everybody, as i feared the wiring connections are all pretty good as i expected them to be with the new loom (Greg Bender) i have tried to contact somebody mentioned in another post Gloucestershire way to see if i can get it refurbed just need to hope the couriers keep going for a bit as i said im in lockdown just awaiting notification from the NHS as to how long!!!!!!
Thanks again all stay safe
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Richard Hyatt
Senior Member Joined: 14 Oct 2019 Location: Dorset Status: Offline Points: 1097 |
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Just before you dismantle everything.
I think an earlier Let mentioned battery voltage. Put your voltmeter across the battery , nothing turned on , should be about 12.4 to 12.6 volts. Ok? Leave it on there and turn the ignition on and press the starter button. Ok it's sluggish , but what do the volgmeter read whilst it is spinning sluggishly ? You don't want it to go below 10.5 or 10.7 really during cranking. If it does , how old is the battery? Give it a good charge? What's the electrolyte level ? Above the plates ? Assuming it's a lead acid and with screw tops of course?
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red leader one
Senior Member Joined: 07 Oct 2014 Location: Cullercoats Status: Offline Points: 4466 |
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Are you one of the 1.5 million people who have/are had/getting a letter from the Goberment?
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oscar225
Senior Member Joined: 03 Nov 2018 Location: Devon Status: Offline Points: 204 |
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Apparently yes not holding my breath though, work have already arranged to get my van collected next week and off hire it, maybe they know something that i dont?
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