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Husqvarna LTH18538 wont start pls help
#1
F
Floyd Baxter
F
Floyd Baxter
Hi all. This is driving me nuts. new battery (verified over 12v), new starter, new magneto from flywheel to spark plug, new spark plug, tried 2 new starter solenoids, replaced ignition switch, replaced blade push button safety switch, replaced brake push button switch and still no luck. Ground wires look fine---I even undid ground, scraped paint, and put back. Battery to solenoid is hot (lights up) but not hot to starter from the solenoid. It tries weakly to turn over but not near enough to start. I took another battery and connected directly to starter, as a bypass---no luck. Today I even bought a new cable and connected it direct from starter solenoid to starter and no luck (I was guessing existing cable could have a cut in it---how I dont know). Fuse near starter solenoid looks fine. I don't see any wires out of place or cut up.
Here's the big clue: upon turning key there's a loud noise below the battery (which is under the seat and where the solenoid is). The noise is not just a mild click, its more a rattling, and its loud. Strangely even when I'm not sitting on the mower this noise happens (I'd have thought the seat safety switch would not allow anything to happen at all). This is a briggs 18.5hp INTEK. I'd hate to pay to have it hauled in and have it be an easy fix. It was kind of fun initially but now I'm going nuts, although not in a huge hurry given its November.
My last guess is alternator but I am skeptical and only guess that because I have no other ideas. Safety switch under seat maybe? I doubt that one too.
thoughts?
Here's the big clue: upon turning key there's a loud noise below the battery (which is under the seat and where the solenoid is). The noise is not just a mild click, its more a rattling, and its loud. Strangely even when I'm not sitting on the mower this noise happens (I'd have thought the seat safety switch would not allow anything to happen at all). This is a briggs 18.5hp INTEK. I'd hate to pay to have it hauled in and have it be an easy fix. It was kind of fun initially but now I'm going nuts, although not in a huge hurry given its November.
My last guess is alternator but I am skeptical and only guess that because I have no other ideas. Safety switch under seat maybe? I doubt that one too.
thoughts?
#2
dougand3
dougand3
If you take red jumper cable from a battery in a running car directly to stater pos lead and black jumper cable to starter ground (many times just the starter mounting bolt) and starter does not spin....1 bad starter (could be bad bendix gear) 2. bad starter ground 3. obstruction blocking flywheel/crankshaft. Can you turn flywheel screen by hand?
#3
F
Floyd Baxter
F
Floyd Baxter
tried direct from car to starter (black on frame/ground of tractor and red to starter bolt) and no change...just weak attempt at crank. Starter is brand new and I suspect the old one is good too because when I turn key this noise is for sure at the starter solenoid. However, I've tried 3 solenoids. Flywheel can turn---nothing blocking.
Not sure what you mean by ground of starter---there's a wire that grounds to the magneto at the flywheel and another that is a safety thing w/the carb.
With this noise I'm thinking HAS to be starter solenoid but again, I've tried 3. Have also bridged starter solenoid posts to bypass and no luck. I'm stumped
Not sure what you mean by ground of starter---there's a wire that grounds to the magneto at the flywheel and another that is a safety thing w/the carb.
With this noise I'm thinking HAS to be starter solenoid but again, I've tried 3. Have also bridged starter solenoid posts to bypass and no luck. I'm stumped
#4
B
bertsmobile1
B
bertsmobile1
Floyd.
Following is my standardized test for diagnosing mower problems
If you would like assistance from me then please do all of them exactly as written and post the results.
I have some thought from what you have already posted but best to keep them till you have substabtiated them by doing all the tests.
I like to start from the starter motor and go backwards .
Do the following 5 tests, regardless of the results from an or all of them as there can be more than one problem and you want to isolate where the problem lies.
Elimination of individual parts is important so you know by the end, the battery, solenoid & heavy power circuits are all in good order.
1) try to jump the starter motor directly from your car or truck.
Starter turns = starter good
2) do the same directly from the mowers battery
Starter turns = mower battery good
No turn = duff battery, recharge it & try again.
3) check for voltage ( + 12V ) at the solenoid trigger wire with the key in start position
3a) same with ground trigger wire ( 4 wire solenoid ) or body of solenoid ( 3 wire solenoid)
( I like to test V from the battery hot terminal to ground terminal rather than ohms as they give funny readings )
4) leave ground jumper in place ( from step 2 ) & try key start.
Starter turns = power connection good but ground connection suspect ( most common )
Confirm it by trying again, extra ground removed
I run a secondary ground from the grounding bolt to one of the starter mounting bolts & paint over both with liquid electrical tape.
5) Remove the trigger ( thin ) wire / wires from the solenoid.
Ground one & bridge from the hot terminal to the other.
Starter cranks = solenoid good.
Solenoid is not polarity sensitive, BUT THE WIRING IS so make sure you remove the thin control wires.
Note a thinner wire on the hot terminal is not a control wire. It is the main power feed to the mower.
From here on things become very mower dependant as starting circuits are getting changed all the time.
Basically the power goes in a loop from the hot side of the solenoid ( saves wire, no other reason ) through the fuse to the B terminal on the key switch then to the PTO switch then to the parking brake switch then to the solenoid trigger switch , easy peasy after you grow the 3rd arm. Use a test lamp and follow the power.
However a lot of mowers with a 4 pole solenoid, run a secondary ground control circuit to the ground solenoid wire through the lap bars.
Then to stop this interfearing with the normal safety function of the ground kill, it goes to a relay with the ground as the switched connection.
These are a PIA as the + control wire to the relay comes from the power loop above and the ground side of the control comes via the normal cut out functions of the lap bars.
Be very careful because if you have a system like this and accidentally send 12V down the ground loop you can fry the magnetos on some circuits.
Following is my standardized test for diagnosing mower problems
If you would like assistance from me then please do all of them exactly as written and post the results.
I have some thought from what you have already posted but best to keep them till you have substabtiated them by doing all the tests.
I like to start from the starter motor and go backwards .
Do the following 5 tests, regardless of the results from an or all of them as there can be more than one problem and you want to isolate where the problem lies.
Elimination of individual parts is important so you know by the end, the battery, solenoid & heavy power circuits are all in good order.
1) try to jump the starter motor directly from your car or truck.
Starter turns = starter good
2) do the same directly from the mowers battery
Starter turns = mower battery good
No turn = duff battery, recharge it & try again.
3) check for voltage ( + 12V ) at the solenoid trigger wire with the key in start position
3a) same with ground trigger wire ( 4 wire solenoid ) or body of solenoid ( 3 wire solenoid)
( I like to test V from the battery hot terminal to ground terminal rather than ohms as they give funny readings )
4) leave ground jumper in place ( from step 2 ) & try key start.
Starter turns = power connection good but ground connection suspect ( most common )
Confirm it by trying again, extra ground removed
I run a secondary ground from the grounding bolt to one of the starter mounting bolts & paint over both with liquid electrical tape.
5) Remove the trigger ( thin ) wire / wires from the solenoid.
Ground one & bridge from the hot terminal to the other.
Starter cranks = solenoid good.
Solenoid is not polarity sensitive, BUT THE WIRING IS so make sure you remove the thin control wires.
Note a thinner wire on the hot terminal is not a control wire. It is the main power feed to the mower.
From here on things become very mower dependant as starting circuits are getting changed all the time.
Basically the power goes in a loop from the hot side of the solenoid ( saves wire, no other reason ) through the fuse to the B terminal on the key switch then to the PTO switch then to the parking brake switch then to the solenoid trigger switch , easy peasy after you grow the 3rd arm. Use a test lamp and follow the power.
However a lot of mowers with a 4 pole solenoid, run a secondary ground control circuit to the ground solenoid wire through the lap bars.
Then to stop this interfearing with the normal safety function of the ground kill, it goes to a relay with the ground as the switched connection.
These are a PIA as the + control wire to the relay comes from the power loop above and the ground side of the control comes via the normal cut out functions of the lap bars.
Be very careful because if you have a system like this and accidentally send 12V down the ground loop you can fry the magnetos on some circuits.
#5
F
Floyd Baxter
F
Floyd Baxter
bertsmobile1,
thanks, i'll try to get to this (but day job in the way so might not be quick).
need clarification on a few things.
I have 4 post solenoid...when you say "3a) same with ground trigger wire ( 4 wire solenoid ) or body of solenoid ( 3 wire solenoid)
( I like to test V from the battery hot terminal to ground terminal rather than ohms as they give funny readings )"
I'm not sure what exactly is the ground trigger wire on the solenoid. I'm not at the tractor now but there are 2 things that clip onto thin metal posts off the solenoid....I'm sure one of these is ground---you mean test this? And I have a meter that lights up only---do I need to buy a micrometer?
when you say thin control wires at the solenoid are you meaning the ones that clip onto the solenoid? or do you mean the thin red wire that has round connector to the solenoid post?
thanks, i'll try to get to this (but day job in the way so might not be quick).
need clarification on a few things.
I have 4 post solenoid...when you say "3a) same with ground trigger wire ( 4 wire solenoid ) or body of solenoid ( 3 wire solenoid)
( I like to test V from the battery hot terminal to ground terminal rather than ohms as they give funny readings )"
I'm not sure what exactly is the ground trigger wire on the solenoid. I'm not at the tractor now but there are 2 things that clip onto thin metal posts off the solenoid....I'm sure one of these is ground---you mean test this? And I have a meter that lights up only---do I need to buy a micrometer?
when you say thin control wires at the solenoid are you meaning the ones that clip onto the solenoid? or do you mean the thin red wire that has round connector to the solenoid post?
#6
M
mechanic mark
M
mechanic mark
How many CCA'S does your new battery have? New battery should have a date of manufacture stamped on it.
#7
B
bertsmobile1
Remote starter solenoids come 2 ways
1) 3 post , 2 for the battery / starter cable + 1 x 12 V trigger the body is ground
2) 4 post , 2 for the battery / starter cable + 1 x 12 V trigger + 1 x ground trigger, body is insulated
The trigger can be either the + terminal or the - terminal or both
So you need to check that one of these wires shows 12V & the other shows ground when the key is in the start position.
It confuses a lot of people that you can use either the + side or the - side to switch
The electricity has to do the full loop from one side of the battery to the other so a break in either side will prevent the circuit being complete & nothing happens.
Most of the switches on mowers are ground circuits so if you get a short to ground it is very hard to find and the mower stops dead in it's tracks.
B
bertsmobile1
bertsmobile1,
thanks, i'll try to get to this (but day job in the way so might not be quick).
need clarification on a few things.
I have 4 post solenoid...when you say "3a) same with ground trigger wire ( 4 wire solenoid ) or body of solenoid ( 3 wire solenoid)
( I like to test V from the battery hot terminal to ground terminal rather than ohms as they give funny readings )"
I'm not sure what exactly is the ground trigger wire on the solenoid. I'm not at the tractor now but there are 2 things that clip onto thin metal posts off the solenoid....I'm sure one of these is ground---you mean test this? And I have a meter that lights up only---do I need to buy a micrometer?
when you say thin control wires at the solenoid are you meaning the ones that clip onto the solenoid? or do you mean the thin red wire that has round connector to the solenoid post?
Remote starter solenoids come 2 ways
1) 3 post , 2 for the battery / starter cable + 1 x 12 V trigger the body is ground
2) 4 post , 2 for the battery / starter cable + 1 x 12 V trigger + 1 x ground trigger, body is insulated
The trigger can be either the + terminal or the - terminal or both
So you need to check that one of these wires shows 12V & the other shows ground when the key is in the start position.
It confuses a lot of people that you can use either the + side or the - side to switch
The electricity has to do the full loop from one side of the battery to the other so a break in either side will prevent the circuit being complete & nothing happens.
Most of the switches on mowers are ground circuits so if you get a short to ground it is very hard to find and the mower stops dead in it's tracks.
#8
F
Floyd Baxter
F
Floyd Baxter
None of this works. I get rapid clicking at solenoid still. I thought maybe ground from battery negative to frame so I scraped off the paint—-no help—-there’s a bolt anyway. It only cranks when I have outside battery directly to starter (black on mower frame and red on starter bolt). But this really a weak crank—no enough to start.
One more theory—-this mower has safety solenoid at the carberator——-possibly relevant? I’d think if it was involved I’d get not even a weak crank though?
One more theory—-this mower has safety solenoid at the carberator——-possibly relevant? I’d think if it was involved I’d get not even a weak crank though?
#9
B
bertsmobile1
B
bertsmobile1
Did you do the first bit and try rotating the engine by hand ?
You should be able to put your palm on the debris guard and rotate the engine.
Take the plugs out.
If it spins fine plugs out but won't spin plugs in then the next suspect is the valve lash being out of adjustment over riding the decompressor.
As for starter cables , water wicks into the cables between the strands and pools where the cable bends,
It then corrodes the cable wires so when yu check volts, it is good, when you test Ohms, it tests good but under load will not carry amps.
It would have helped me a lot if you had done as asked and posted the results of every step in the testing sequence rather than just saying none worked.
The tests were specifically designed to confirm items are either working or not working so your response tells me nothing at all.
It is very difficult doing "Agony Aunt" diagnosis on the web when all we have to go on is what you type.
It is really important that you do exactly as asked so that readers can follow what has been checked and cross that off their list.
Also an actual engine number off the rocker cover would be really helpful .
IT allows readers to pull up engine diagrams so we know what type of compression management your engine has.
These are really simple engines usually with really simple problems .
Do you still have the old starter ?
Does it spin hard when connected to a battery ?
Was the starter a genuine B & S one, or bought from a real mower store so is certified to be good, or the cheapest one you found on the web ?
With the rocker cover off you should see the inlet valve either bump open just before TDC on compression stroke.
Or stay slightly open till about 1/2 way up on the compression stroke.
You should be able to put your palm on the debris guard and rotate the engine.
Take the plugs out.
If it spins fine plugs out but won't spin plugs in then the next suspect is the valve lash being out of adjustment over riding the decompressor.
As for starter cables , water wicks into the cables between the strands and pools where the cable bends,
It then corrodes the cable wires so when yu check volts, it is good, when you test Ohms, it tests good but under load will not carry amps.
It would have helped me a lot if you had done as asked and posted the results of every step in the testing sequence rather than just saying none worked.
The tests were specifically designed to confirm items are either working or not working so your response tells me nothing at all.
It is very difficult doing "Agony Aunt" diagnosis on the web when all we have to go on is what you type.
It is really important that you do exactly as asked so that readers can follow what has been checked and cross that off their list.
Also an actual engine number off the rocker cover would be really helpful .
IT allows readers to pull up engine diagrams so we know what type of compression management your engine has.
These are really simple engines usually with really simple problems .
Do you still have the old starter ?
Does it spin hard when connected to a battery ?
Was the starter a genuine B & S one, or bought from a real mower store so is certified to be good, or the cheapest one you found on the web ?
With the rocker cover off you should see the inlet valve either bump open just before TDC on compression stroke.
Or stay slightly open till about 1/2 way up on the compression stroke.
#10
F
Floyd Baxter
F
Floyd Baxter
delayed closure on this: had nothing to do w/anything being discussed on forum. Had to take to a repair guy who fixed it. Was some kind of flaw w/the camshaft. Said pretty common so I was surprised it didn't come up here. Has been running perfectly since
#11
Scrubcadet10
Scrubcadet10
Probably the automatic compression release. Common on Briggs Intek 31 and 33 series models with the 793880 camshaft, but can happen on any engine.delayed closure on this: had nothing to do w/anything being discussed on forum. Had to take to a repair guy who fixed it. Was some kind of flaw w/the camshaft. Said pretty common so I was surprised it didn't come up here. Has been running perfectly since
#12
B
bertsmobile1
B
bertsmobile1
At a guess he fitted a cheap knock off cam.
Not a problem with genuine cams and very few of the techs here will fit parts of unknown quality so not a common problem to us .
Thanks for the feed back & hope all goes well.
Not a problem with genuine cams and very few of the techs here will fit parts of unknown quality so not a common problem to us .
Thanks for the feed back & hope all goes well.