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2015 Toro v-twin won't start
#1
D
dtestin
D
dtestin
Adjusted the coils and valves. I have spark but not sure how strong the spark should be, for comparison. Battery is charged and engine spins well, plenty of compression. Fresh gas and cleaned carb. I even sprayed a bit of starter fluid in the cylinders after checking for spark. Would not even fire once. What else should I check?
#2
R
Rivets
R
Rivets
Check to see if you’ve given us enough information to help you. Do you think if you told us the model and serial numbers of the unit it would help us? What about the make, model and serial numbers would give us an idea of which of the hundred possible engines you have? Was this problem ongoing or just happened recently? We are not standing next to you, with a strong drink in our hand, to see what you have!! You need to help us before we can help you.
#3
D
dtestin
D
dtestin
Here is additional information Toro MX4250 74760 315002651 June 2015 24.5hp 708cc Loncin 2P77F engine. It had been hard starting and occasionally backfiring when starting last year. It did not want to start when hot. I had adjusted the valves last year and that did not seem to help. I cleaned the carb and adjusted coil gap a couple weeks ago when I got fresh gas. I do have spark but I am not sure if it is strong enough - nothing to compare it to. I even sprayed a little starter fluid in the cylinders after checking spark and did not get ignition. Battery seems to be fine and was charged over the winter. How strong should the spark be?
#4
R
Rivets
R
Rivets
Spark is spark, trying to explain how it should look is impossible. From what You tell us I would recommend you check valve clearance. I’ve attached a Loncin service manual which should help you out. https://www.toro.com/getpub/117255
#5
M
Midnight_Rider
M
Midnight_Rider
Place engine in a fairly dark area and spin it over while grounding the spark plug to the engine..You want a bright blue colored spark,not a weak white or yellow colored spark.. you need at least 90 psi to start an engine and it to run well.. If you have good enough compression,blue spark,good fresh fuel and it's making it into and out of the carb along with clean air and still doesn't start then I'd check the flywheel key to see if it's sheared and spun the flywheel making the timing so far off..
#6
D
dtestin
D
dtestin
If I don't have that bright blue spark, does it mean I likely need new coils? It seemed at least one of the coils might have been touching the flywheel before I adjusted them. Would that damage the functionality of the coil?Place engine in a fairly dark area and spin it over while grounding the spark plug to the engine..You want a bright blue colored spark,not a weak white or yellow colored spark.. you need at least 90 psi to start an engine and it to run well.. If you have good enough compression,blue spark,good fresh fuel and it's making it into and out of the carb along with clean air and still doesn't start then I'd check the flywheel key to see if it's sheared and spun the flywheel making the timing so far off..
#7
StarTech
StarTech
If you see the spark it usually strong enough. Trying going the color is going cause problems as different environments will produce different color sparks depend the air chemical make up. The test for how strong it is if it can jump a .166 spark gap it is strong enough.
Have checked for a sheared flywheel key? Kinda rare on riders but if someone previously had the flywheel off they might have not torque it to spec.
You got to fuel, air, compression, and spark at the right time.
Have checked for a sheared flywheel key? Kinda rare on riders but if someone previously had the flywheel off they might have not torque it to spec.
You got to fuel, air, compression, and spark at the right time.
#8
R
RevB
R
RevB
Just running a compression test tells you nothing of condition of the internals. You'd need a differential tester to determine where the compression is going after the valves close. Adjusting a poorly seated valve only gets you a properly adjusted valve that won't hold compression. All of this is just to say check valve face condition. If you have used ether and gotten nothing that's pretty telling as simple static discharge will light up ether immediately even at concentrations of just 1.9% by volume. The prior hard starting indicates a progressive issue.
#9
D
davis2
and giggles? Sometimes it works...
D
davis2
Did you try a new plug forAdjusted the coils and valves. I have spark but not sure how strong the spark should be, for comparison. Battery is charged and engine spins well, plenty of compression. Fresh gas and cleaned carb. I even sprayed a bit of starter fluid in the cylinders after checking for spark. Would not even fire once. What else should I check?
and giggles? Sometimes it works...
#10
M
Midnight_Rider
M
Midnight_Rider
Usually it doesn't kill the coil if it touches unless the flywheel grinds the coils face then it could.. you can use a multimeter to test the coils,youtube has many tutorial videos on testing.. Have you tried a new spark plug as I've seen instances where the plug would fire outside the cylinder but wouldn't fire off fuel when installed... A blue spark is ovtained when all electrical components are in their best shape and the engine is making good strong spark and is what I always look for when troubleshooting..If I don't have that bright blue spark, does it mean I likely need new coils? It seemed at least one of the coils might have been touching the flywheel before I adjusted them. Would that damage the functionality of the coil?
#11
StarTech
StarTech
For the one millionth+ time you can not fully test ignition coils that has the electronic trigger enclosed in the coil. In order to test these other than plug and play requires a very expensive tester that most shops don't have. You can only test the secondary side (high voltage side)
#12
R
rhkraft
R
rhkraft
I am thinking it is out of time. Spark plug wires reversed? Other timing issues? I saw this happen on an old pickup truck in 1976 when one of my employees took out the distributor to install new points and re-installed the distributor 180 degrees out of phase.
#13
R
rhkraft
R
rhkraft
I am thinking it is out of time. Spark plug wires reversed? Other timing issues? I saw this happen on an old pickup truck in 1976 when one of my employees took out the distributor to install new points and re-installed the distributor 180 degrees out of phase.
#14
J
johnny7
J
johnny7
any update to your issue? I'm following and curious as to the resolution.Adjusted the coils and valves. I have spark but not sure how strong the spark should be, for comparison. Battery is charged and engine spins well, plenty of compression. Fresh gas and cleaned carb. I even sprayed a bit of starter fluid in the cylinders after checking for spark. Would not even fire once. What else should I check?
#15
D
dtestin
D
dtestin
I am going to check the flywheel shear pin but not until about 3/16. Maybe plugs and recheck valve clearances if the pin is good. Compression is about 150/145.
#16
C
Chipg1956
C
Chipg1956
Usually all these small V twins will start and run on one cylinder so it seems likely that you have a problem that effects both, most of which have already been suggested. I have found that many Kawasaki's have a tendency to cut spark plug wires on sharp sheet metal, you should check this to prevent future problems. I have also found that most of the v twins produce enough power that they can be running on one cylinder and the owner will not even notice. Therefore it is possible that you have 2 separate problems that effect the cylinders.
#17
Etbrown44
Etbrown44
If it won't fire on starting fluid, and if you have compression, chances are it's the plug or ignition.
Get a spark tester on amazon for $8. Set it for 10mm or lawn mower.
Get a spark tester on amazon for $8. Set it for 10mm or lawn mower.
#18
VRR.DYNDNS>BIZ
VRR.DYNDNS>BIZ
The color f the spark tells you about the weather, not the value of the spark. Spark jumping the proper gap is proper spark but I suspect your flywheel key is partially or totally sheared changing the timing of the spark.Place engine in a fairly dark area and spin it over while grounding the spark plug to the engine..You want a bright blue colored spark,not a weak white or yellow colored spark.. you need at least 90 psi to start an engine and it to run well.. If you have good enough compression,blue spark,good fresh fuel and it's making it into and out of the carb along with clean air and still doesn't start then I'd check the flywheel key to see if it's sheared and spun the flywheel making the timing so far off..
#19
T
TobyU
Only the old engines that were horizontally opposed typically had a coil with two wires coming out of it and even then they designed it sometimes so they wouldn't reach to the other plug but in reality it probably wouldn't have mattered much. Lol
Most of the ones like the v-twins all have two individual coils so you certainly couldn't reach the plug wire to the opposite side because it wouldn't be long enough.
Typically if you can see any spark at all, or if it will tickle your fingers when you spin it by hand a little bit which I don't like to do because I hate to be shocked, then it's fine spark wise.
The next thing to do is always give it an external fuel source because about 9 plus times out of 10 it is not getting enough fuel so I always start there instead of starting a spark.
If it doesn't fire that way or if it pops or does anything odd then it's not a bad idea to check the flywheel key but I typically just pull both plugs out and stick my finger in the hole and spin it over to make sure it goes puff puff puff puff puff and then it never sucks my finger in the hole or does a double puff or irregular pattern etc.
So out of the few that it's not fuel related from my first test, I'm able to determine that it's a cylinder compression valve problem by the second test because either I will have no compression or it will try to suck my finger back in the hole which means the valves are not closing properly for the no compression or when it sucks your finger back in it means the intake isn't opening so you probably have rocker arms loose or hanging there or been pushrods etc.
Another option on the one cylinder without compression is that the Piston isn't moving up and down from a snapped Rod so you want to look in there with a flashlight or stick a straw or something in the hole to make sure you can prove the piston is going both up and down repeatedly.
This diagnostic procedure will lead you to the problem over 98 times out of 100.
Now fixing the problem of why you may not have compression in one cylinder or why it may be sucking your finger in and not opening the intake valve is a different matter but that normally does not involve removing the head but most people's first step is just start yanking things apart and pull the head off when it's not even necessary.
Another good percentage go out and buy a new head and waste somewhere between 85 and 185 when they did not have to do that at all.
If you do find that push rods, it is highly unlikely to fix it by putting new push rods in because most likely they will bend immediately on spin up because typically that is a slipped valve guide which is preventing the valve from moving far enough when the rocker arm pushes on it and the weak link is the push rod when they have aluminum push rods. When they don't, it often tears the rocker arm.
As you can tell, I've seen a lot of these. Far more than I wish existed because it's just shoddy execution of a fairly decent design and situation but they drop the ball at the end making things durable enough by simply pressing valve seats in and valve guides in and not using loctite or a lock washer on the rocker arm studs into the head and simply not making the valve train adjustments and fasteners durable enough to hold things in place without vibrating loose.
This is different than the head gasket blowing problem on the Briggs which is a design flaw and not execution of the assembly.
T
TobyU
But highly unlikely if not impossible to happen on a lawn mower.I am thinking it is out of time. Spark plug wires reversed? Other timing issues? I saw this happen on an old pickup truck in 1976 when one of my employees took out the distributor to install new points and re-installed the distributor 180 degrees out of phase.
Only the old engines that were horizontally opposed typically had a coil with two wires coming out of it and even then they designed it sometimes so they wouldn't reach to the other plug but in reality it probably wouldn't have mattered much. Lol
Most of the ones like the v-twins all have two individual coils so you certainly couldn't reach the plug wire to the opposite side because it wouldn't be long enough.
Typically if you can see any spark at all, or if it will tickle your fingers when you spin it by hand a little bit which I don't like to do because I hate to be shocked, then it's fine spark wise.
The next thing to do is always give it an external fuel source because about 9 plus times out of 10 it is not getting enough fuel so I always start there instead of starting a spark.
If it doesn't fire that way or if it pops or does anything odd then it's not a bad idea to check the flywheel key but I typically just pull both plugs out and stick my finger in the hole and spin it over to make sure it goes puff puff puff puff puff and then it never sucks my finger in the hole or does a double puff or irregular pattern etc.
So out of the few that it's not fuel related from my first test, I'm able to determine that it's a cylinder compression valve problem by the second test because either I will have no compression or it will try to suck my finger back in the hole which means the valves are not closing properly for the no compression or when it sucks your finger back in it means the intake isn't opening so you probably have rocker arms loose or hanging there or been pushrods etc.
Another option on the one cylinder without compression is that the Piston isn't moving up and down from a snapped Rod so you want to look in there with a flashlight or stick a straw or something in the hole to make sure you can prove the piston is going both up and down repeatedly.
This diagnostic procedure will lead you to the problem over 98 times out of 100.
Now fixing the problem of why you may not have compression in one cylinder or why it may be sucking your finger in and not opening the intake valve is a different matter but that normally does not involve removing the head but most people's first step is just start yanking things apart and pull the head off when it's not even necessary.
Another good percentage go out and buy a new head and waste somewhere between 85 and 185 when they did not have to do that at all.
If you do find that push rods, it is highly unlikely to fix it by putting new push rods in because most likely they will bend immediately on spin up because typically that is a slipped valve guide which is preventing the valve from moving far enough when the rocker arm pushes on it and the weak link is the push rod when they have aluminum push rods. When they don't, it often tears the rocker arm.
As you can tell, I've seen a lot of these. Far more than I wish existed because it's just shoddy execution of a fairly decent design and situation but they drop the ball at the end making things durable enough by simply pressing valve seats in and valve guides in and not using loctite or a lock washer on the rocker arm studs into the head and simply not making the valve train adjustments and fasteners durable enough to hold things in place without vibrating loose.
This is different than the head gasket blowing problem on the Briggs which is a design flaw and not execution of the assembly.
#20
G
Gord Baker
When the blade(s) strike a solid object the key is designed to shear partially or completely so the Crankshaft is not damaged. Replace key with an OEM one.
G
Gord Baker
Pull off the Recoil cover and carefully inspect the Keyway and Crankshaft key. Slots should line up exactly.Adjusted the coils and valves. I have spark but not sure how strong the spark should be, for comparison. Battery is charged and engine spins well, plenty of compression. Fresh gas and cleaned carb. I even sprayed a bit of starter fluid in the cylinders after checking for spark. Would not even fire once. What else should I check?
When the blade(s) strike a solid object the key is designed to shear partially or completely so the Crankshaft is not damaged. Replace key with an OEM one.
#21
J
Joed756
J
Joed756
As long as you're spinning it up in the dark, reinstall the plug and see if you see any spark when you turn it over. I've seen automotive plugs with internal shorts under compression that allow the spark to jump to the engine head, bypassing the cylinder.Place engine in a fairly dark area and spin it over while grounding the spark plug to the engine..You want a bright blue colored spark,not a weak white or yellow colored spark.. you need at least 90 psi to start an engine and it to run well.. If you have good enough compression,blue spark,good fresh fuel and it's making it into and out of the carb along with clean air and still doesn't start then I'd check the flywheel key to see if it's sheared and spun the flywheel making the timing so far off..
#22
D
dtestin
D
dtestin
Flywheel key is not sheared, lines up perfectly. I was hoping that was the issue.Pull off the Recoil cover and carefully inspect the Keyway and Crankshaft key. Slots should line up exactly.
When the blade(s) strike a solid object the key is designed to shear partially or completely so the Crankshaft is not damaged. Replace key with an OEM one.
#23
D
dtestin
D
dtestin
Adjusting valves: rocker is sloppy side to side and moving it around allows the feeler gauge to slip in and be the right feel. Is this typical?