WM starter Benny Hill Show

[pamtnman]

OK so this has not been a dull subject away from the keyboard. As some of you may recall, a lot of good suggestions were made here, and most were implemented or tried. The LT35 had been to a mechanic once already for this electronic issue, back in the Fall, and last week I trailered the mill back to the same place. I brought with me the best problem solving WM staff could offer over the phone, which boiled down to a wire going bad or being chewed by a rodent. The mechanic hunted down each wire connection and did, in fact, find a shaky connection at the engine. Machine started up, ran great, I was called and told to come and get it. I said "OK, I will be there in two days. Each morning, start the machine and let it run for a couple minutes. Come back at the end of the day and do it again." And wouldn't we know it...regardless of how much reconnecting loose wires the mechanic had done, the sawmill continued to run for a while and then snap the fuse off the key start switch. So this morning, the mechanic installed a relay off the switch. I think someone here (above) had suggested this relay solution, and because I am not allowed near fire, mechanical objects, or electricity, I just filed it away in the "That Guy Knows Something" folder. I did direct the mechanic to look at this thread, and I think he might have. He also consulted with another mechanic in the region. Anyhow, the relay is in and they are going to do the same start run and restart routine tomorrow. If that seems to have solved it, then the sawmill will get trailered back up to the mountains....

[Ben Cut-wright]

OK so this has not been a dull subject away from the keyboard. As some of you may recall, a lot of good suggestions were made here, and most were implemented or tried. The LT35 had been to a mechanic once already for this electronic issue, back in the Fall, and last week I trailered the mill back to the same place. I brought with me the best problem solving WM staff could offer over the phone, which boiled down to a wire going bad or being chewed by a rodent. The mechanic hunted down each wire connection and did, in fact, find a shaky connection at the engine. Machine started up, ran great, I was called and told to come and get it. I said "OK, I will be there in two days. Each morning, start the machine and let it run for a couple minutes. Come back at the end of the day and do it again." And wouldn't we know it...regardless of how much reconnecting loose wires the mechanic had done, the sawmill continued to run for a while and then snap the fuse off the key start switch. So this morning, the mechanic installed a relay off the switch. I think someone here (above) had suggested this relay solution, and because I am not allowed near fire, mechanical objects, or electricity, I just filed it away in the "That Guy Knows Something" folder. I did direct the mechanic to look at this thread, and I think he might have. He also consulted with another mechanic in the region. Anyhow, the relay is in and they are going to do the same start run and restart routine tomorrow. If that seems to have solved it, then the sawmill will get trailered back up to the mountains....

"wire chewed by rodent" would present as an open or short.Since your problem includes blowing fuses a short seems more likely...if rodent damage was the cause. The circuit in question is mostly open to visual inspection if rodent damage has been done.  They don't remove electrical protective covers and then close the bag to keep the wires fresh. 
 
Describe "shaky connection".

As to the "relay off the switch", at best this is a band aid that will most likely confuse or complicate future testing and diagnosis.  The components, as supplied, are capable of handling the current they are designed to handle.  If the fused circuit powering the device, or short, is the same rating, it will continue to blow. If it doesn't, the mechanic has dug another rabbit hole.

In amongst all this consulting, did WoodMizer indicate modifying the wiring was a good procedure? Please get someone with electrical diagnostic capabilities to do some hands on amperage and voltage testing of the circuit this has been narrowed down to.

[SawyerTed]

Ben is correct.  Adding complexity on top of a faulty circuit doesn't repair the fault.   

Somewhere there is a fault that causes more than 10 amperes of current to flow.  The fuse is the protection to prevent excessive heat and burning up the wiring, components or worst case the entire sawmill.  

[pamtnman]

Sure seems to me the relays are added because the process of deduction through trial and error, which was heavily recommended and seconded here, has been employed and implemented. Hopefully it is the correct fix. The LT35 is back at the mill landing, surrounded by logs, and will hopefully begin working tomorrow. Lot of orders piled up, lot of logs piled up, and railroad ties are $41.50 delivered, which is basically a buck a board foot and real good money. One thing that really caught my eye is the LT35 machine hours on its clock went from 252 at drop off to 360 hours at pickup on Friday. The mechanic looked hard at the clock and said "I doubt this thing ran more than thirty minutes total the entire time it has been here." Definitely something awry with the electrical system on this LT35. 

[Southside]

Well that's a hint that something is amiss in the key switch circuit.  That hour meter isn't the type that runs off the spark plug impulse, rather it runs off the key switch being in the "on" position.  Somehow power is getting to the "on" pole of that switch when it should not.  

[Maine Miller]

 

 


Pages from my book. My mill is a 2017 LT35HD w/25HP Kohler

[Hilltop366]

It might have only run 30 min but if the key only has to be on it could have been left in the on position for a few days?

I'm still wondering how a split second short to ground to blow the fuse would ruin a key switch which makes me suspect the key switch itself is the issue. I figure either the switch manufacture started making the switch cheaper or the the supplier changed sources to a cheaper switch that will handle the load for a while in a perfect world until it isn't and then it won't.

So if that is the issue then adding a relay to the start circuit will reduce the load on the switch. Time will tell.

Another cause of failure for the switch to short out would be the switch falling apart inside, a bit of time with a ohm meter and the old switch then taking the switch apart would answer some questions.

Don't forget that most small engines are ground to kill so there is a source to ground inside the switch.

[Ben Cut-wright]

(1) It might have only run 30 min but if the key only has to be on it could have been left in the on position for a few day

(2) I'm still wondering how a split second short to ground to blow the fuse would ruin a key switch which makes me suspect the key switch itself is the issue. I figure either the switch manufacture started making the switch cheaper or the the supplier changed sources to a cheaper switch that will handle the load for a while in a perfect world until it isn't and then it won't.

(3) So if that is the issue then adding a relay to the start circuit will reduce the load on the switch. Time will tell.

(4a)Another cause of failure for the switch to short out would be the switch falling apart inside, a bit of time with a ohm meter and the old switch then taking the switch apart would answer some questions.

(4b)Don't forget that most small engines are ground to kill so there is a source to ground inside the switch.

(1) Leaving the "key on" for a few days normally results in a dead battery. 

(2)The result you suspect requires specific faults in order to have the results you surmise. The normal "load" this switch is supposed to accommodate isn't that much.

(3)  The relay alone will NOT *protect a properly fused circuit.

(4 a&b)  The wiring diagram does NOT depict a source of ground in the ignition switch.  The engine uses an electronic ignition module and the wiring diagram shows the ignition switch controlling battery power to the ignition module.  If the switch failure was due to "falling apart" the relay will not provide relief. 

It appears "adding a relay for start function" of the ignition switch is the repair attempt?  If that is so, leaving the ignition switch on for an infinitive number of hours would not be testing the start function.  It could only prove the problem was not in other circuits. 

[Hilltop366]

1) Does not need to be all at once but adding up time it was worked on and time left on while not worked on (still sounds like a lot of time) Is there any load on the battery when the key is left on? I don't know enough about that mill to answer.

2) Agree however "The result you suspect requires specific faults in order to have the results you surmise." applies to any function or malfunction. Either the switch failed causing the problem or the problem (short) causes the switch to fail and nobody found the short so I wanted to point out the other option.

Don't you find it odd that the key switch fails at the same time as the fuse blows or that the switch fails with such a small load while fuse protected? I'm assuming and hoping that the fuse is at the beginning of the circuit and protecting the complete circuit.

3) I have no idea how the relay circuit was installed just pointing out that it would reduce the load on the switch assuming the low power side of the relay is drawing less than the starter solenoid, seems likely it would however I do not have the specs for either.

If the relay was installed the most obvious way (to me) it would use the key switch to low side of relay and a new circuit from fused power to relay then to starter solenoid. Still all protected.

4) I do not have access to wiring diagram, thanks for info, If the switch internally "falls apart" the relay will not provide relief however if the wire to solenoid was replaced it would eliminate original wire as a suspect. This could have been done without a relay too.

I still go back to this:

Don't you find it odd that the key switch fails at the same time as the fuse blows or that the switch fails with such a small load while fuse protected?

If I recall this has happened twice which keeps me suspect.

[Ben Cut-wright]

(1) Key on supplies battery voltage to the ignition module, the proof meter, and the alternator, as well as the ACC circuits. 

(2) I read this to mean his components failed, but testing did NOT identify the cause.

(3)There has been NO description of  how relay-s were installed. Like, you I would think from the conversation the relay was for the starter solenoid.  There was NO mention of the relay circuit being fused. No mention of what connections were made to utilize a relay.  Was the purpose to unload the ignition switch or the start circuit wiring? IOW, what portion of the circuit was the relay install attempting to correct? The switch or the fused wiring to the solenoid. 

All this is conjecture as NO test results have been provided.  Listing the failed parts, even listing the parts or repairs-done do little to explain what was/is the problem.

(4) "falling apart" was only a suspected fault, not confirmed.  Yes, the starter solenoid wiring is very minor.  Even less so than wiring in a relay.

Don't you find it odd that the key switch fails at the same time as the fuse blows or that the switch fails with such a small load while fuse protected?

Don't think that is how the failure was described.  The first switch was replaced just *cause he ordered other parts. His friends ?discovered the second switch was the cause of  the no start. 

If I recall this has happened twice which keeps me suspect.

It would indeed be strange if the fuse did not protect the ignition switch on two so closely related occasions.  I didn't read it that way though. 

[Hilltop366]

 

[Maine Miller]

The pics I posted don't appear to be easily zoomed in on, but one thing I noticed......there are no 10 amp fuses on the diagram or parts list

[Ben Cut-wright]

Miller,  I notice your age and number of posts are the same in your last reply.


You are correct about there being "no 10 amp fuses in the diagram or parts list".  I mentioned that in a previous reply.  The diagrams I've seen show a five amp fuse on the start solenoid circuit, and circuit breakers on the other circuits. 


(I asked about this in an early reply but never got an answer)
IF this starter fuse is blowing only during starting attempts, as it appears to be doing, the circuit in question isn't vast or complicated.  Even the most rudimentary tests should resolve his issue. Haven't read of any engine or operational difficulties. Appears the engine was operating just fine when shut down and then the starter fails to operate on restart.  Better explanation, or confirm understanding, of precisely when the fuse blows might help. 

IF, the starter solenoid fuse blows during normal engine/mill operation, rather than only at starting attempts, it is truly a mystery.  There is NO power from the switch through this fuse during engine running.  There is NO load on this fuse except during start function. 

Ignition switches were replaced but not because of confirming test results.  It is NOT a test to replace multiple components then condemn a single component as the faulty one. I understand the OP said the Ohmmeter showed several ignition switch terminals to be OPEN. There was no mention of which terminals or switch position. OHMS testing the terminals of an ignition switch is sketchy even if the test is preformed properly by a tech who knows what to expect. 

[Maine Miller]

My diagram does not have a 5 amp fuse either, but there is one in my book designated as D24 that has the 5 amp fuse.
My diagram is designated G25 for gas 25 HP, so I guess the other must be for a 24 HP Diesel?

[Ben Cut-wright]

My diagram does not have a 5 amp fuse either, but there is one in my book designated as D24 that has the 5 amp fuse.
My diagram is designated G25 for gas 25 HP, so I guess the other must be for a 24 HP Diesel?

I don't see either a 5amp fuse on the  starter solenoid or a circuit breaker on the ignition circuit in your diagram. The wiring diagram I'm referring to includes those items along with an asterisk, (*) after each one. The reference at the bottom of the page, for the 25 gas engine, denotes F3 and CB6 were "added 07-18". Neither of these are called out on the parts list. Not sure what revisions we are looking at but the wiring appears to be the same. 

[Magicman]

I questioned this fuse situation very early on during this discussion and stated then that if the circuit was properly fused/breaker, the fuse would blow and no damage would be incurred to the key switch.  The OP stated that the fuse blew plus the start switch was burned up which indicated that the circuit was "over fused".  Replacing a 5 amp fuse with a 10 is a recipe for bad things to happen.

[SawyerTed]

It's just not possible to understand electricity for other people.  

[Ben Cut-wright]

Fuses are normally used to protect the cabling, IE; the wiring. If the fuse being repeatedly blown is in fact the fuse for the starter solenoid circuit, the wire from the switch to the fuse, or the wire from the fuse to the solenoid, should have failed long before the switch failed.  Switches and connectors have, by design, much greater current carrying capacity than the wiring in a circuit. Using a fuse of *higher amperage than the wiring rating should damage the wiring long before the higher amperage fuse causes damage to the switch.

The above is common theory of fused circuit protection as it applies to the circuit in question, not applicable to all/every circuit design.

[pamtnman]

Well today is the day to put this all to the test. The angry clients wanting their lumber must be served. I hope this fix works. The mechanic said that he and another guy who has worked on the WM LT35 concluded that the wire serving the starter was too thin, too small, and could not handle the surge. Hence the fuse popping. I don't know how many other LT35s have experienced this, but it does not sound like a lot. 
I do appreciate the helpful suggestions, thank you. Every one of them has been suggested to the mechanic, and I believe he went online and looked at this comment thread. 

And for the guys who like to snipe and make fun of people asking for help, if it makes you feel good, go ahead and do it. It does not bother me. I don't understand how some people have so much time on their hands to follow up on their inclinations! 

Before I forget: When I started the machine yesterday, engaging the clutch resulted in a lot of bad noise. Turns out that someone at the shop had tested the blade on something hard. The new blade that the machine had gone in with came back with a lot of broken and bent teeth. The roller guides are not shiny, so the blade was not run long. It looks like someone tried something brief and then walked away leaving it messed up. Kind of like when I was twelve and found my dad's adult magazines...guys will never change. Lesson I learned is, don't send the machine in to the shop with a blade on it. Someone somewhere around that shop will be tempted to run it and try something stupid. Better to keep the blade off.

[pamtnman]

I questioned this fuse situation very early on during this discussion and stated then that if the circuit was properly fused/breaker, the fuse would blow and no damage would be incurred to the key switch.  The OP stated that the fuse blew plus the start switch was burned up which indicated that the circuit was "over fused".  Replacing a 5 amp fuse with a 10 is a recipe for bad things to happen.

I am finding my way on this subject. Obviously other people have more experience and have more and better insights. It is WM techs who said they are including 10 Amp fuses off the key start switch now, so don't look at me for this step. And it also turns out that the key start switch is fine. It is not burning up. At least not the latest one. 

[Southside]

Ever figure out how you ended up with 100 hours on the clock?

[beenthere]

pamtnman
For sure I am not going to return/reply to your woes. 

Wish you well.

[Magicman]

I am replacing the second bad key start switch now, with a different make than what WM uses. If this one goes, then there is definitely something overloading the switch itself. Yes, the sawmill runs great, runs great, runs great and then pfft the 10A fuse off the key switch blows and the multimeter shows that the switch is no longer functioning properly

I was only responding to what was written and the way I read it, the fuse as well as the key switch were blown.  My only purpose for responding to this topic has been to offer suggestion and to be helpful.

Hopefully you are on track to solving your woes.

[Ben Cut-wright]

(1)The mechanic said that he and another guy who has worked on the WM LT35 concluded that the wire serving the starter was too thin, too small, and could not handle the surge. Hence the fuse popping.

(2)And for the guys who like to snipe and make fun of people asking for help, if it makes you feel good, go ahead and do it. It does not bother me. I don't understand how some people have so much time on their hands to follow up on their inclinations!

(3)Before I forget: When I started the machine yesterday, engaging the clutch resulted in a lot of bad noise. Turns out that someone at the shop had tested the blade on something hard. The new blade that the machine had gone in with came back with a lot of broken and bent teeth. The roller guides are not shiny, so the blade was not run long.

(4)Lesson I learned is, don't send the machine in to the shop with a blade on it. Someone somewhere around that shop will be tempted to run it and try something stupid. Better to keep the blade off.

(1) ONE thing I can tell you for sure.  A "too small wire" is NEVER the cause of blown fuses. 
 
(2) Lotta folks have generously spent time and effort to give what advice they could. Ain't going on anything but memory but I don't recall anyone "making fun."

(3) If you are leaving blades on the mill for extended periods of time when not in use, there is another lesson which will benefit you. Not a good idea.

(4)The ONLY time I've ever heard a blade make noise during initial clutch engagement is when it is not properly tensioned prior to use. And, yes the noise is terrible because the teeth are striking rigid steel and likely to cause "broken and bent teeth". Why was your blade making "a lot of bad noise"?

Was the "additional relay circuit" the fix?  Or, was a heavier wire used to replace the starter solenoid wire? Or.....?  I do hope whatever was done will eliminate the problem. 

[cook]

I wonder if this may not be a current draw problem but a voltage spike issue across the fuse from the  ignition system and yes an intermittent bad ground or coil could cause this to happen