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honda 4518 no spark

#1

G

grbuch

have a honda 4518 without spark no 12 volts at primary side of coil. Could this be cdi unit ?


#2

B

bertsmobile1

The information I posted below ( now changed to red ) is wrong as it applies to the 4514 not the 4518

Your engine has a self energizing magneto with a hall effect trigger module contained within the magneto coil
Thus what you think is the primary power feed to te coil is actually the ground wire that goes from open circuit ( running ) to ground ( stopping ) .
IF you tried to test the coil by flicking 12 V across that wire then you have destroyed the hall effect trigger chip and the coil ( now called a module ) is ruined
If you did not try to energize the coils, remove the kill wire and crank the engine
If you get a spark then the magnetos are fine if you do not get a spark they are toast .
Check the wire with the brake on, drive in neutral, PTO off & key switch on it should be open circuit ( to ground ) and should go to ground the instant any one of these happens
1) blade switch gets turned on
2) brake gets taken off
3) key switch is turned off .
IF you have cooked the coils, double check that in no configuration of the controls battery voltage shows on that wire
The coils for your engine will come up as NLA but you can fit the latter model coils
They are wider so you will need to make up a longer stud to fit the coil & blower housing on and fit a slightly longer bolt on the other side
Note these are handed left & right .
The left hand one goes on the left hand cylinder as viewed from the drivers seat
I have a mixed pair on my mower , original right & later coil on the left


#3

G

grbuch

bertsmobile1 said:
Your engine has a self energizing magneto with a hall effect trigger module contained within the magneto coil
Thus what you think is the primary power feed to te coil is actually the ground wire that goes from open circuit ( running ) to ground ( stopping ) .
IF you tried to test the coil by flicking 12 V across that wire then you have destroyed the hall effect trigger chip and the coil ( now called a module ) is ruined
If you did not try to energize the coils, remove the kill wire and crank the engine
If you get a spark then the magnetos are fine if you do not get a spark they are toast .
Check the wire with the brake on, drive in neutral, PTO off & key switch on it should be open circuit ( to ground ) and should go to ground the instant any one of these happens
1) blade switch gets turned on
2) brake gets taken off
3) key switch is turned off .
IF you have cooked the coils, double check that in no configuration of the controls battery voltage shows on that wire
The coils for your engine will come up as NLA but you can fit the latter model coils
They are wider so you will need to make up a longer stud to fit the coil & blower housing on and fit a slightly longer bolt on the other side
Note these are handed left & right .
The left hand one goes on the left hand cylinder as viewed from the drivers seat
I have a mixed pair on my mower , original right & later coil on the left
Click to expand...
Well I have not gotten back to garage yet but from what you say Iam sure the damage is already done. I wish I would have said this first before I tried to trouble shoot the old fashion way. I will probably get rid of this mower. Will get back later after I do your checks. Thanks so much for your input,I really did like this mower.


#4

B

bertsmobile1

An appology to start with.
I was getting your mower confused with the 4514H which I have worked on and has a std water cooled mower engine in it
The 4518 used the 18Hp Honda car engine which actually has a battery ignition so please disregard my previous post
The engine is very much worth fixing as they will run forever and you will not get a better mower now days for under $ 20,000


#5

G

grbuch

No apology needed I understand. That actually is good news. I havent given up on the 4518,just on back burner for awhile. I have a service manual and just a few steps away from last few checks,pulser charger and the charging coil both of these if bad require the front of engine and flywheel to be removed,just not ready to tackle this till it gets warmer. My garage is chilly. Thanks and if you have any sugestions keep me informed.


#6

T

tombauer

Not a Honda car engine!! Used in some other Honda equipment. I just don't know why people give such bad advice about these tractors, one of the best Honda ever made. The 4518 uses a CDI ignition and the pickup coil never goes bad, there is no exciter coil, the CDI is powered by the battery and yes if you expected there to be 12 volts at the coil, nope. There is never any measurable voltage at the coil. I make NEW electrical parts for ALL the Honda tractors, even the 6522 diesel.
Tom


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