getting signal to new solenoid, still won't engage starter

ChrisBFRPKY

Member
Joined
Sep 24, 2020
Threads
0
Messages
25
You have 12v and it drops to 6v when you try to start it..........all switches and solenoids have been replaced with known good ones........Ground wires checked........Battery cables checked.....load test the battery, it's gotta be bad.
 

StarTech

Lawn Addict
Top Poster Of Month
Joined
Feb 19, 2020
Threads
5
Messages
2,287
I would suggest installing a help relay as it appear to be a voltage drop problem.
 

cbs123

Member
Joined
May 26, 2020
Threads
6
Messages
24
Something not right. If light is same brightness should have enough current the power solenoid.
If you connect wire from batt+ to small terminal on solenoid engine cranks over at proper speed (y/n)
Remove trigger wire from solenoid and connect meter from batt- to trigger wire and turn key to start. What is the potential voltage measured?
Reattach trigger wire to solenoid. Connect meter to batt- and trigger wire connection at solenoid. Turn key to start. What is measured voltage?
Move meter to batt + and trigger wire connection at solenoid. Turn key to start. What is the circuit voltage measured?


Thanks again for the help everyone. We never could figure out the problem, although it did seem to get better about cranking with the key. The battery seemed to have plenty of voltage and amperage, because you could jump the solenoid and it would spin and crank very easily. Just when you tried it with the key it would just click alot. Voltage getting all the way to solenoid (single post solenoid) but just click click click. Touch it one time with jumper wire and cranks easily every time. We even tried jumping every safety terminal with short pieces of jumper wire to try to narrow down the problem and it would still do it. Checked and cleaned connections more times than I can count and still had the problem. I told the customer what was happening and suggested the only solution might be to replace the entire harness, although I could see nothing wrong with the old one. No melted ends, or corroded ends.

Gotta love electrical problems
 

Rivets

Lawn Royalty
Joined
Mar 11, 2012
Threads
45
Messages
10,556
To me that sounds like a bad ground on the solenoid. If you have a four terminal solenoid, figure out which of the small terminals is going to ground and either replace it, or make sure the end which is attached to the frame is clean and tight.
 

Fish

Lawn Addict
Joined
Aug 2, 2013
Threads
11
Messages
4,528
Go out tonight and turn the key in the dark while someone watches, if you see a spark, that will be the weak connection.
 

Telesis

Active Member
Joined
Apr 19, 2017
Threads
0
Messages
84
Post #13 is key here. He verified in that post he's seeing a 6V drop in the positive chain when trying to start. As others have mentioned, you need to take your meter and ground the - lead and work your way back from the solenoid to the battery and measure the voltage on each side of every device WHILE THE KEY IS IN THE START POSITION, in other words, under load. The voltage across all safety switches, PTO switch, ignition switch etc that are in series between the battery and the solenoid need to be measured. In a perfect world, only one of those devices is causing the 6 volt drop and that's what needs to be replaced. However don't be surprised if you see a couple of volts being dropped across multiple switches. Then you have multiple contributors to the problem. To be clear, the readings are meaningless without the load of the solenoid coil with the key in the start position. I promise you Ohm's law is still in effect here!

As Star Tech mentioned, you may find it easier to put in a helper relay. I did. I have a JD170 tractor(with Kaw motor) that was prone to this clicking problem and I had no desire to replace all the intermediate safety switches, ignition switch etc. Hasn't clicked once since. [google AM107421 for more info] This is the fix JD came up with as a field retrofit. In a nutshell you are using the trigger wire to power an external relay you locate near the starter assembly and it switches local battery power to the solenoid. The external relay is a much lighter load as it has a coil resistance of say 80 ohms drawing only 150mA as opposed to the solenoid which requires a number of amps which is over 10X more current. There is a much lower voltage drop through whatever extra resistance is in your trigger wire 'chain' (i.e. dirty/corroded switches/wires/connections) when 150mA or so is flowing vs the solenoid amperage.
 

bertsmobile1

Lawn Royalty
Joined
Nov 29, 2014
Threads
41
Messages
16,271
FWIW,
I use a stack of bypass jumpers , short wires with a 1/4" spade terminal each end for the purpose of diagnosis .
I jump every switch then jump the B & S terminals on the key switch
No joy = bad connection or broken wire

If it fires right up then it is a matter of reconnecting all of the switches one at a time till it dosen't fire & you have the guilty party .

OTOH the relay to trip the solenoid isa very good idea and used on most of the better mowers where penny pinching to a rock bottom retail price is not part of the agenda
 

cbs123

Member
Joined
May 26, 2020
Threads
6
Messages
24
To me that sounds like a bad ground on the solenoid. If you have a four terminal solenoid, figure out which of the small terminals is going to ground and either replace it, or make sure the end which is attached to the frame is clean and tight.
Thanks for the reply. The solenoid is made onto the starter and the entire starter is grounded directly to the battery with a big wire, 4 guage or whatever is used on mowers. Also have replaced the solenoid with the same problem. I believe the solenoid grounds through the starter when you bolt it all together
 
Top