Starter delayed disengagement

[Mark]

It started to get a bit sticky couple of years ago, hangs on for a second or so but recently started getting worse, last start it stayed engaged to flywheel for about 3 seconds after starting.

sorry dont have a good photo of starter and attached photos the aftercooler is removed for servicing.

Any advice before i start pulling things apart?

Thanks in advance
Mark

Topic

[Neto]

Congrats on fixing it! I had a problem with my starter recently, sometimes I pushed the start button and it would not do anything but you would notice that smoke was comming from the starter cable so and starter was not doing anything. I changed the mag switch, cleaned everything and still did it one more time. I got scared of the situation and decided to just get new batteries and a brand new Delco 38mt starter to replace the old 42mt. My guess is that either one of the batteries was causing a short or the starter bendix was and lots of amps were getting pulled.

[Mark]

Its fixed, pilot relay was sticking. I stripped it down cleaned it out, there was a gooey substance on the contacts. you could feel it stick when you operated it mechanically without power.

Think I also noticed a contributing problem. Someone has mounted it horizontally to the side of the engine block. So it relies on the internal spring to return the armature to its disconnected position. Ive had this spring in my hand its not very big or strong. Im going to make a new bracket to hold the relay vertically, so gravity will assist the armature contacts to fall away from the power side terminals. Vertically, it should even work if the spring fails. Ide like to see the spec sheet for this relay to see if its approved for horizontal duty, either way Im changing it to vert.

 

[Mark]

Thanks for taking the time to reply Clark,

So from your description, it sounds like its a typical starter say like a chevy. relies on the solenoid for electrical connection and thro out of the pinion gear with same mechanical action. ( with upstream elec pilot solenoid as well)

I will play around with a test lamp and determine if its an electrical delay or mechanical within the starter.
I started it again today and it hung on for a second or two but I didnt do any testing as it was a quick visit.

will check properly soon

Mark

[Clark Leighs]

The most likely problem is the starter solenoid contacts are sticking thus not breaking the circuit to the pinion and the actual motor.

It could also be the pilot relay not releasing for the same reasons.

THe pilot is between the ignition sw. and the starter solenoid. The ign. sw. is protected from electrical backflash by the pilot relay. When you turn the key that energizes the pilot relay [small terminals] . THe pilot relay large terminals connect the starter solenoid coil to the battery. The starter solenoid then does two things, drives the pinion into mesh with the flywheel and at the last bit of movement makes the heavy current connection between the starter motor and the battery.
Check that pilot relay which is quite near the starter. If it is hanging up the starter can hang up. Replace it.

If the pilot is OK then the starter solenoid is most likely at fault. If so then remove the starter and get it rebuilt or exchange for rebuild.

There are other possibilities but those two are most likely.

Also spray the ign. switch with something like WD40 to prevent it from hesitating.

Almost forgot. Do not hesitate to get it sorted. You have had a warning. Heed it. One time the starter will hang, the engine will over speed it and something will break and cause damage, maybe to the flywheel.

[Author]

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