Wamsutta
Well-known member
When they turn the engine over quickly most of the time, but every once in a while act like the engine is seized up, that's a sign the starter motor is on its way out, correct? Battery voltage is 14.6V.
Starter Motors
- Thread starter Wamsutta
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seber
Well-known member
Garden tractors do that quite often. For small engines, it is just normal. I've never looked into why.
It could be anything.
A common fault in old (70s/80s) vehicles I see is the ignition switch or wiring can no longer handle the high current of the solenoid on a pre-engaged starter. The result is usually that the stater randomly won't work but will usually randomly start working again.
Your fault is likely a poor connection or contact somewhere. Voltage testing is required. I wouldn't suspect the starter without further diagnostics like measuring the current with an oscilloscope.
A common fault in old (70s/80s) vehicles I see is the ignition switch or wiring can no longer handle the high current of the solenoid on a pre-engaged starter. The result is usually that the stater randomly won't work but will usually randomly start working again.
Your fault is likely a poor connection or contact somewhere. Voltage testing is required. I wouldn't suspect the starter without further diagnostics like measuring the current with an oscilloscope.
is it by chance temperature related ?
joel63
Well-known member
I think it's time for the VR drop test, and battery starting voltage test.
I'm assuming this is in your LeSabre?
Be careful of the remans. The original starter in my olds 88 lasted 150,000 miles. First replacement lasted about a year before it started cranking slow. Warrantied it and worked find the first winter. Next year it was back to the same thing of cranking slow in the cold. It always started it but there was days where it made me wonder.
This year I got the newer style gear reduction starter. So far it's working fine. I think a good working direct drive starter spins the motor faster.
Be careful of the remans. The original starter in my olds 88 lasted 150,000 miles. First replacement lasted about a year before it started cranking slow. Warrantied it and worked find the first winter. Next year it was back to the same thing of cranking slow in the cold. It always started it but there was days where it made me wonder.
This year I got the newer style gear reduction starter. So far it's working fine. I think a good working direct drive starter spins the motor faster.
Overhead needs run or decompression might be broken
jayemm
Well-known member
With GM (3800-2 V6) I only used AC Delco remans for starters and alternators. Weren't cheap but they gave reliable service and had a good warranty. My understanding is that the rebuilders had to adhere to GM mandated quality/reman criteria to use the AC Delco name. I remember getting a starter with the test data sheet filled out by the test technician. This was a long time ago so maybe things changed. At the time, the other quality rebuilds were offered by Bosch.
SwissMetric
Well-known member
After checking the battery as well as the voltage drop when starting, ideally at the main + terminal of the starter I'd check both high current paths, i.e. + and -. Due to high currents even small contact resistances can make a major difference. Especially corrosion and too low contacting forces can easily increase resistance. Once I had to install a new high section (low AWG/MCM) "jumping" cable in a protective flexible tubing.
Crimpings should be flawless. As high currents only flow while starting, using a thermal camera is probably tricky. I never used one to check that though routinely inspect non-residential switchgear panels.
Many starters are straightforward to disassemble and often the problem is quite obvious, e.g. damaged collector, burnt stator winding or worn out pinion. In several cases I remember brushes were still intact.
Crimpings should be flawless. As high currents only flow while starting, using a thermal camera is probably tricky. I never used one to check that though routinely inspect non-residential switchgear panels.
Many starters are straightforward to disassemble and often the problem is quite obvious, e.g. damaged collector, burnt stator winding or worn out pinion. In several cases I remember brushes were still intact.
Diagnostic tool is a good VOM. Measure voltages while slow cranking is happening from batt + terminal tp batt =. Then work your way back batt + to live terminal on starter. Next look at voltage between engine block and batt - terminal. Finally look at voltage between batt - and a very good contact place on the car body. In my experience people chase the + side of DC circuits and never think about the - side from load back to battery that completes the circuit. I get a chuckle out of people having to replace starters as most times the "cure" was moving the cable connections during installation. I have repaired literally thousands of cars, trucks, boats, airplanes over the years and might have needed 10 starters in total due to actual failure - and most of that just the main contacts. I have as yet to ever replace one of my own starters - and I keep cars and trucks until they are fully used up. The original starter in my FLD120 now has 1,800,000 kms on it over 29 years - the battery ground cables and connections have caused poor starting a few times and have needed replacement or cleaning.
rust in the eye
Well-known member
"act like the engine is seized up"? So doesn't turn at all and a hard thunk as the gear engages?
14.6v at the battery? Battery needs to be checked with engine off. 13.6 is fully charged
Integral solenoid or divorced?
Ah, old style GM.
Assuming good connections:
I suspect your solenoid could be causing the issue. The solenoid performs two tasks; moving the drive gear into engagement with the flywheel and, importantly here, closing the high current contacts to the starter motor. The contacts get burned over time and cannot flow enough current. In my young broke days my solution was to dismantle the solenoid, flip the contact disc over to a fresh surface and also rotate the wire terminals 180* for a likewise fresh surface. Once apart this is self explanatory.
14.6v at the battery? Battery needs to be checked with engine off. 13.6 is fully charged
Integral solenoid or divorced?
Ah, old style GM.
Assuming good connections:
I suspect your solenoid could be causing the issue. The solenoid performs two tasks; moving the drive gear into engagement with the flywheel and, importantly here, closing the high current contacts to the starter motor. The contacts get burned over time and cannot flow enough current. In my young broke days my solution was to dismantle the solenoid, flip the contact disc over to a fresh surface and also rotate the wire terminals 180* for a likewise fresh surface. Once apart this is self explanatory.
Last edited:
danielbuck
Well-known member
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- Apr 15, 2014
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I generally don't care about keeping my old vehicles original or original spec. I usually toss in a gear reduction starter, alot less weight to deal with, and although I know a lot of old starters will last damn near for ever, it seems like the newer gear reduction units are quite reliable as well.
in a lot of cases, a direct drive starter is faster, but the speed isn't constant, they're slowed down by compression. gear reduction are higher torque, so they have a more constant speed. on high compression engines, a gear reduction can have higher speed approaching TDC than a DD, which is where you want it, either for getting a charge to fire on diesels, or on spark ignition.
Wrench97
Well-known member
Starters will do that when the bushings wear and the armature starts to drag or the brush contact in poor from use
Voltage drop test the negative side(battery post to block the positive also if you can get to it
If the both are .5v or below it's starter time.
The current Delco(Remy) rebuilds are nothing but problems they are no longer part of GM.
We use Denso when available, Autozone New units only, last resort Quality Rebuliders.
Voltage drop test the negative side(battery post to block the positive also if you can get to it
If the both are .5v or below it's starter time.
The current Delco(Remy) rebuilds are nothing but problems they are no longer part of GM.
The Delco Remy name is now used by BBB industries who at one time made a decent rebuild so maybe there is hope at the end of the tunnel we won't install them any longer.
We use Denso when available, Autozone New units only, last resort Quality Rebuliders.
I just noticed it takes slightly more cranking time before the engine starts vs a good working direct drive.
The POS remans would really crank slow in the cold but were fine in warmer weather.
I got an AC Delco for an '05, or thereabout, LeSabre. GM used gear reduction starters in the factory on the later years of the 3800.
oldmachinenut
Well-known member
This may sound ridiculous but flex both your battery cables looking for any stiff/non flexible sections. GM used copper clad aluminum battery cables on some vehicles and acid from the battery can wick into the cable and corrode it inside the plastic jacket. I have cut the stiff sections open and found only white corrosion powder and the wire nearly gone.
Jasmith801
Member
Most likely cause on a small engine for this is valves out of adjustment causing the compression release to not work correctly
whateg01
Well-known member
12.6 VDC is a fully charged lead acid battery.
seber
Well-known member
That's the second reply like that. First, garden tractors do not have compression release. Second, valve adjustment is part of my standard maintenance on every one I work on.
Old Man Roger
Well-known member
That’s a low battery, should be 12.5 or better.
plenty of garden tractors have compression releases. what machine are you talking about?
put a charger on that, but given you said the voltage was 14.6 earlier, it's probably time for a new battery. Doesn't mean the start isn't going bad, too, of course.
Jasmith801
Member
They sure do on the camshaft it’s a small eccentric that opens up the valve slightly
seber
Well-known member
I work on John Deeres with Kawasaki and Yanmar motors. So far I have not bothered with the 100 series units from the big box stores.
richfinn
Well-known member
This is why I always carry a DC Amp Clamp (mines good to 600A), if it draws a lot of current when it's misbehaving, you just ruled out any battery or voltage drop issues and condemned the starter motor (assuming nothing belt driven is seized and preventing normal cranking).
If it draws little to no current then you start looking at voltages/solenoids etc.
Throw in an oscilloscope and you will likely catch the issue even when it cranks
If it draws little to no current then you start looking at voltages/solenoids etc.
Throw in an oscilloscope and you will likely catch the issue even when it cranks
rust in the eye
Well-known member
11.9 v is considerably low, fully charged is 13.6
If problem persisits with a topped off battery I'd be looking at connection integrity* given your mention of the problem manifesting when heat soaked.
*This is exacerbated with a low battery trying to push current through a restriction..
Ain't old cars fun?
If problem persisits with a topped off battery I'd be looking at connection integrity* given your mention of the problem manifesting when heat soaked.
*This is exacerbated with a low battery trying to push current through a restriction..
Ain't old cars fun?
rust in the eye
Well-known member
You are correct, 12.6, not 13.6
senior moment
joel63
Well-known member
rust in the eye
Well-known member
Better yet are old cars that have been accessorized*, modified or been at the hands of hackers*.Old cars are perfect for honing electrical troubleshooting skills.
Currently sorting an old MB C107 that has seen all three. So far have removed 5# or so of wire added for bogus accessories or bypasses of factory wiring because they didn't want to/care to/learn to repair correctly with intended parts. Add in that somebody reshuffled wires in some connectors for good measure.
*I'm looking at you alarm & stereo installers.