Kawasaki FH580V V-twin RPM drops when PTO engaged

flintknapper

LawnSite Senior Member
No I did not replace the coils. If there was an issue with the coil won't my battery not charge and I would have a dead battery? My battery is fine and no problem starting the engine.

I did find the connections of the starter solenoid off the battery were loose. The two[2] ring terminals are on the post of the solenoid are on the post but not clamped down tight. The two[2] ring terminals one lead goes to the positive of the battery and the other lead goes to the ignition switch. I tried to tighten the nut on the solenoid stud but the nut has fused to the copper post and I can't tighten the nut.

I just ordered a new solenoid
I am thinking maybe since the ring terminals are not held tight that maybe the vibrations from the mower running with the blades engage is resulting in intermittent connection resulting in not enough electric current to fully engaged the Electromagnetic PTO Clutch. Could this be possible?

What should the nut that goes on the copper stud of the solenoid be made of?
Should the nut be steel, aluminum or stainless so it does not fuse/corrode ?


The ignition coils *that fire your spark plugs* is what he was talking about. Not your 'stator' that charges the battery.

Do you have a mini-tach you can use to see what the engine rpm is 'WOT' unloaded and again when you engage the PTO so we have an idea what we are dealing with?

A weak coil can cause the drop in rpm you are seeing when under load.
 

ed2hess

LawnSite Fanatic
I was thinking
The ignition coils *that fire your spark plugs* is what he was talking about. Not your 'stator' that charges the battery.

Do you have a mini-tach you can use to see what the engine rpm is 'WOT' unloaded and again when you engage the PTO so we have an idea what we are dealing with?

A weak coil can cause the drop in rpm you are seeing when under load.
Pull plug wires off one at a time
 
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ComfortControl DD

LawnSite Member
Its possible he is running on just one cylinder....in which case pulling the plug wires one at time would quickly tell. Wouldn't hurt to check. Thumbs Up
Hello flintknapper & ed2hess,

Thank you so much for your input. Sorry for my stupidity forgetting the coil is solely for the spark and the stator charges the battery. I know this stuff from years of fixing engines but I am just forgetting stuff with my age.

I believe flintknapper solved my problem but want you guess to confirm it.

I ran the engine with PTO disengaged, remove plug wire, engine still runs


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Gee coils must be good, right???


I then ran the engine with PTO engaged remove plug wire engine dies

PTO engaged remove plug wire engine dies



Is this typical, coil works under no load and then coil doesn't work under load? So don't you agree the coil towards the rear of the deck is bad?

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If you agree the coil is bad, now the question is should I just replace both coils?

I went to https://www.kawasakienginesusa.com/...c90842/e59f4761-7ca1-46d1-aeba-795a32106738/y

The COIL-ASSY-IGNITION part is 21171-7034

Looks like if I buy from https://www.kawasakienginestore.com/kawasaki-21171-7034
cost is $63.79 for 1 coil.

Should I trust buying from ebay, always worried about a knock-off or aftermarket?

Hopefully the coil is the problem, but regardless thank you to everyone that read this post and provided input.
 

fastline

LawnSite Member
You bet!!!! That is a win right there! Once I heard the first vid, I knew this did not sound fuel related. Either valves were too tight, or ignition and it sounded like it was running on one cylinder.

What I recommend is pulling that spark plug that is deemed dead and verify it is black and wet. That will ensure you are fueling. It will be important to do an oil change and replace that spark plug. However, I VERY much recommend changing that spark plug and trying it first. Some spark plug failures act odd and I have tripped me up a few times.

Also do a quick check on the plug wire and cap. Sometimes those fall apart and nothing actually wrong with the coil pack.

great job!

Oh, to answer your question, what is likely happening is very weak but present spark, but when you load the engine up, you are getting what we call "spark snuffing" where all the fuel just blows out the spark kernel.
 
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ComfortControl DD

LawnSite Member
You bet!!!! That is a win right there! Once I heard the first vid, I knew this did not sound fuel related. Either valves were too tight, or ignition and it sounded like it was running on one cylinder.

What I recommend is pulling that spark plug that is deemed dead and verify it is black and wet. That will ensure you are fueling. It will be important to do an oil change and replace that spark plug. However, I VERY much recommend changing that spark plug and trying it first. Some spark plug failures act odd and I have tripped me up a few times.

Also do a quick check on the plug wire and cap. Sometimes those fall apart and nothing actually wrong with the coil pack.

great job!

Oh, to answer your question, what is likely happening is very weak but present spark, but when you load the engine up, you are getting what we call "spark snuffing" where all the fuel just blows out the spark kernel.
I removed the spark plugs and the spark plug is not wet.

The first plug I removed is towards the front of the machine (near gas tank) and this plug shows more carbon on the plug. I feel this coil is good since when I remove the spark plug cap (coil) with the PTO engaged the engine dies.

The plug towards the rear of the machine (near starter) this plug shows less carbon but it is not wet. This is the coil I thought was bad


When I pull the spark plug off while the engine is running were is this gas going? I assume it is getting blown out the exhaust but couldn't some of the gas get mixed in with the engine oil? When I pull the tip stick out and smell the oil I don't smell any gas.


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So now I switched out the same spark plugs putting the front plug in the back / and the back in the front.

First run mower with PTO disengaged and pulled off each spark plug cap and the engine does not shutdown.

Then I ran mower with PTO ENGAGED and pulled off each spark plug cap and the engine does not shutdown.


So the coil and plugs must be good.

The RPM still does not seem to be were it should be but I don't have a tachometer to measure the RPM and just doing this by ear.


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What do you recommend next?
 

fastline

LawnSite Member
Because you seem to be chasing your tail, lets do this.

1. Get brand new spark plugs, gap them for your engine, and install and test
2. If not fixed, and if practical (major tear down), obtain test values (ohms) for your ignition coils and check them. This does not seem to be it but should probably be tested. If they are removable, a mower shop should have an actual spark tester to fire the coils and test that way.
3. If engine has adjustable valves (not hydraulic), engine compression should be tested.
4. Remove airbox lid and filter or entire assembly and hit the PTO and see if there is any change at all.

In your first vid, I could hear what sounded like a miss or unstable rpm. Super hard to troubleshoot with a video but better than nothing! Your engine sounded like it was under major load when the PTO is hit. Like either the engine is way low on power, or something is making the engine work harder than it should. Is that possible? When RPMs do come up, does it seem like it has full power?
 
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ComfortControl DD

LawnSite Member
Here is another video. I put the spark plugs back in their original position and you can see when the PTO is engaged and I pull the spark plug cap towards the front of the mower(near gas tank) that the engine shuts down. Thus one would assume the coil for the spark plug towards the near of the machine (near starter) would be the bad coil.

Immediately after the engine shuts down I remove the spark plugs and you can see they are not wet. I would think if the coil was bad and the spark plug isn't igniting that the plug for the supposedly bad coil would be wet, but the plug is dry.


I just ordered two(2) new champion rcj8y spark plugs since my local auto parts store only had 1 plug in stock. I should have the plugs tomorrow and I'll try running the engine removing the spark plug cap from each cylinder and see if the engine shuts down.

Any input would be greatly appreciated since now I am not 100% sure it is the coil. If the plug isn't igniting where is the gas going? Is it just blowing out the exhaust and should I get a strong smell of gas? If the gas is mixing with the oil would the dip stick show the increase fluid level? The dip stick doesn't show any increase level.

Thanks again.
 

Nelson M Martin

LawnSite Senior Member
Location
Ontario
I would think your spark plugs should be more then just hand tight ...
Or did i just miss something in ur vid when u loosened them with a ratchet?
 

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