Starter Problem

[edbulmer]

I have 671 Detroit Diesels. I had the starter solenoid taken apart and had the contacts cleaned. The motor started but when I shut it down the started kept turning. Do you think that the contacts may have come loose of not have been put back in correctly? Or would it be something else.

[Ex-Calif]

Did the starter keep turning while engaged to the flywheel? i.e. was the engine turning over?

If the starter is running and the gear is not engaged you likely have 2 failures. The solenoid can "spark weld" shut and the bendix is shot or fouled.

It can be repaired. Or it can be replaced.

[edbulmer]

starter turning and engine not engaged. I had to take the battery cable off to get it to stop.

[River Cruiser]

I've seen the contacts weld together when cranking or trying to crank with low battery voltage.


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[sy_gilana]

I also have a DD. Those solenoids, as with all DD parts, are very reasonably priced.

Mine packed up once while drifting toward a friggen volcano that was erupting, You have never seen the screwdriver jump start so fast as that day.

Later I opened the solenoid and found it really worn, arced and pitted. I drilled a hole through a large coin and made new contact washer. It lasted 8 years until I came back this side of the Atlantic and bought a spare in St Maarten, fitted it and kept the coin operated solenoid as a spare.

Get a new one is my advice. You can burn the motor very quickly if it welds in, and you wont hear it behind a 6/71 Jimmy. No ways...

[Ex-Calif]

The coin trick works in a pinch in remote areas - replace the solenoid...

This is where a rap with a hammer sometimes will unstick the contracts. Be careful - I hate using hammers on electrical stuff - LOL...

[a64pilot]

Originally Posted by edbulmer

I have 671 Detroit Diesels. I had the starter solenoid taken apart and had the contacts cleaned. The motor started but when I shut it down the started kept turning. Do you think that the contacts may have come loose of not have been put back in correctly? Or would it be something else.

I think maybe solenoid contacts are like the old points we had in distrubutors in the days gone by, those had hardened surfaces, yes you could file points, but they would burn very quickly once filed

[edbulmer]

We did clean the points but were not able to get the solenoid out to get at the plunger on the back end. Points were very dirty, but my guy says that may have caused the problem as now the front end is working 100 percent and the back end may have problems. Is there a way to get the solenoid out without taking the starter off? When I tried to pull it out could not get it out. It's a big job to take that starter off. (I may have mentioned it's only 3 years old and they put in a cummins starter (perhaps the detroits don't make any more 671 starters)
BTW-when we pulled the contacts out they were like two large bolts with square copper ends attached with clips. Could the contact washers by worn out or missing because that's all we found on the front end.

[Lepke]

I think either the return spring failed or something is binding the solenoid. I am 66 and have been cleaning DD contact points since I was 14. If the points were properly done it is highly unlikely that they welded. Properly done points are like new and unlikely to weld together. Points spark when engaged and over time make pits that reduces contact surface causing the starter to draw more amps. The more amps, the more pitting until either the solenoid becomes erratic or welds itself closed. Keeping the contact points clean greatly extends the starter life. In all those years, I have never bought a new starter or solenoid for a DD. The twin 671's I have now and their starters look to have been made in the early 1950's or before.

[edbulmer]

The big question is though-how to get the soleniod out. Do you have to take the starter out to get it. That starter is so hard to get at. Especially now when the starter is just turning and not engaging with the solenoid. Whaddya thaink?

[a64pilot]

I have always pulled a starter to work on it, but I guess I've not had one that was too awfully hard to pull.
I might suggest that if possible you pull the starter and if there has been enough use to wear the solenoid, then maybe the armature and brushes in the starter should be looked at

[edbulmer]

Has anyone here been able to pull a soleniod out of a Detroit 671? It would be a pain to get that starter out. One of the bolts is underneath the frame for the motor. Very hard to get at.

[delmarrey]

Originally Posted by edbulmer

Has anyone here been able to pull a soleniod out of a Detroit 671? It would be a pain to get that starter out. One of the bolts is underneath the frame for the motor. Very hard to get at.

Welcome to the mechanical world.

Sometimes a specialty tool needs to be made to do certain jobs. Now would be a good time. Rather then when the starter fails.

"Necessity is the mother of invention"

[Blue Stocking]

IF I recall from my alternator shop days, 6-71s use either the Delco-Remy MT-40 or MT-42 starter. So did just about all big US diesels. Parts readily available. Does yours have the cylindrical or the rectangular backplate ?