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Title: Testing a starter motor off the vehicle Post by: mangocrazy on March 11, 2016, 02:51:00 PM I'm laboriously getting a refurbished motor ready to take to France to substitute for the broken one, and I'm now ready to re-fit the starter motor. Before I do, are there any checks I can perform on the bench to see if the starter motor that was fitted to the engine (which has no known provenance) is viable or not? I was thinking of clamping it in the vice and then running leads from a battery to the +ve and -ve terminals. Is this wise or worthwhile? And how do I tell which starter motor terminal is +ve and which is -ve?
Given that it's in a particularly inaccessible area when the engine is in the car, I don't really want to find out I have a duffer when I come to start the motor for the first time. Title: Re: Testing a starter motor off the vehicle Post by: gengis on March 11, 2016, 10:30:51 PM Yes that would be a worth while test.
Clamp starter in vice, connect +ve lead to the vacant terminal on the solenoid usually a M8 copper coloured stud. Then connect the -ve lead to the casing of the starter, next use a smaller wire with croc clips from the +ve solenoid (heavy croc clip) to the spade terminal of the solenoid. This will then energise the solenoid which will switch the main +ve current through to the starter making it spin if it's a good un. This will also check that the solenoid is working correctly. I would also give a drop of oil to the end bearings and the bendix shaft. Please make sure the battery leads are kept isolated from each other during this process. THERE IS A LOT OF ENERGY IN A BATTERY. Title: Re: Testing a starter motor off the vehicle Post by: lukasdeopalenica on March 14, 2016, 08:34:01 AM I would suggest also checking condition of the starter brushes when you have it out. Access to them you will gain after removing of a back cover.
Title: Re: Testing a starter motor off the vehicle Post by: mangocrazy on March 15, 2016, 08:34:33 PM My starter motor solenoid has two contact posts, both with an M8 copper thread. The top one has no obvious connection (other than an internal one, I guess), the lower one has a lead attached which heads off inside the starter motor. Which one should I connect to the +ve terminal on the battery, and which one to the -ve? There is also a small lead with a spade terminal on it that is soldered on to a connection somewhere between the two M8 threads that is flopping about loose.
I tried connecting battery +ve to 'top' connection and -ve to 'bottom' connection and was met with deafening silence. Excuse my numptyness with electrics, but I don't want to do something silly and bugger it up. What should connect to what? Title: Re: Testing a starter motor off the vehicle Post by: gengis on March 16, 2016, 06:12:13 PM Please see picture... -ve lead goes to the metal casing of the starter, +ve lead to the outboard heavy terminal of the solenoid. The small lead clips onto the spade connection, then dab on to the heavy +ve lead to energise the solenoid switching the battery supply through to the starter motor itself. Hope that helps.
Title: Re: Testing a starter motor off the vehicle Post by: mangocrazy on March 16, 2016, 07:51:38 PM Excellent stuff - many thanks! A picture is certainly worth a thousand words in this instance...!
Title: Re: Testing a starter motor off the vehicle Post by: mangocrazy on March 16, 2016, 11:44:17 PM Yup, that works a treat. I was only using a 12Ah motorcycle battery for the test, but as soon as I touched the fly lead to the +ve solenoid terminal the starter whizzed around and flung the pinion down its shaft. Quite made me jump the first time I did it...
Tomorrow I'll inspect the brushes, but from what I've seen I'll be quite happy to bolt that starter motor back onto the engine. Thanks again, gengis... ;D |