View Full Version : Kawasaki FC420V 14 hp coil wire issues

09-03-2009, 11:33 PM
I just bought a scag that won't start it sparks sometimes depending on which way i bend the plug wire before i spend the 50 bucks and buy a new coil and wire is there a way to just replace the wire it seems to be permanently attached to the coil. I have some spare make your own automotive wires laying around.

thanks for viewing

09-04-2009, 07:08 AM
The plug wire is bonded inside the coil, I just replace the whole coil.

09-04-2009, 09:24 AM
yeah it's unfortunate they design it that way you would think the sealed coil would outlast the plugwire, i'll bite the bone and replace it thanks

09-04-2009, 09:56 AM
I just bought a scag that won't start it sparks sometimes depending on which way i bend the plug wire

By any chance do you know where the break is ? You could use a butt connector to splice it back together, I've seen it done on another large mower and it worked for the guy. He some how cut the plug wire with his hedge trimmer :laugh:

09-04-2009, 03:17 PM
i don't, there is some white corrosion coming from where the wire goes into the epoxy on the coil so i think i may be sol.

I may try and cut it off leaving an inch or so and use a butt connector like you stated can't hurt won't cost me anything.

09-04-2009, 04:29 PM
i don't, there is some white corrosion coming from where the wire goes into the epoxy on the coil so i think i may be sol.

Just be ready to get a new coil if that does not work. I don't remember what engine it was on, but the cut was up near the boot. Good Luck

09-05-2009, 04:52 PM
never trust a seller when they say the plug is new... i replaced the plug and viola she fires. but runs like crap so looks like i'm going to be doing some reading on how to adjust carbs.

09-07-2009, 06:27 PM
my problems have shifted slightly i have cleaned the carb out but i'm having trouble identifying what to adjust. I got some info from here http://www.kawpower.com/ but the pdf kinda blows.

Can you folks help me identify what to adjust.


09-07-2009, 08:38 PM
There are only two adjustments on this carb;


Did you remove that black plastic stop cap then remove the adjuster and clean that port as well ?

You could snap the adjuster off removing this stop cap if not careful, Once off screw the adjuster in until it's LIGHTLY seated counting the turns as you go, Then screw it back out for cleaning then screw it back in until LIGHTLY seated and back it out the number of turns you counted.

This will put it back at a good starting point which can be fine tuned from there once the engine is running and warmed up (with the air filter in place).

09-07-2009, 09:09 PM
Restrorob thanks for helping with the photo's

I did not remove that one, i will pull it out and clean as you indicated. Thanks for the response.

09-08-2009, 04:04 PM
i removed the low speed mixture adjustment screw cleaned and replaced as you have indicated thanks again Restrorob.

Seems to still have the same symptoms the low speed screw was set to 2.5 turns from seated (hard to tell where lightly seated is because of the spring)

I"m able to start the mower at part throttle where the main throttle butterfly blade is barely open. It will run at a normal idle til it starts to get warm then it starts to die. I compensate by giving it more throttle it either dies or blows black smoke then sputters from too much fuel then dies.

I've moved the low speed mixture screw in a few turns but it doesn't seem to want to start wide open with the choke on or off.

09-08-2009, 09:59 PM
I take it you never replaced the coil right ?

This is where a in-line spark tester would come in handy so spark could be tested while the engine is running/acting up/shutting down.

The another possibility could be the valves needing adjustment, But since you say there's corrosion on the plug wire near the epoxy I'd lean that way.

Here's the valve adjustment procedure since doing this cost nothing but a little time;


09-08-2009, 11:12 PM
i found this valve adjustment you had posted in a another thread and checked prior to digging into the carb, very helpful both valves within spec. No i didn't replace the coil. I may have some spark issues but i found some books on small engines and want to eliminate the carb first. Also the spark seems blue and strong compared to my running 5.5 briggs walk behind.

Tomorrow i'm going to check governor adjustment. The engine seems to be surging. I also went out and bought a rubber nipple for my blow gun i'm going to go through the carb again. The throttle return spring is pretty weak may replace that.

My next step if that gets me nowhere i will research on how to bench test the carb with a hand pump and possibly rebuild the carb.

Thank you all for viewing and your input.

09-12-2009, 12:17 AM
I took the carb apart again finally got the main jet out cleaned blown etc. While i was blowing out all the other ports i noticed i could not get air through one of them. The red arrow below will not allow air to pass is this normal?


09-12-2009, 01:06 PM
sorry for the double post having picture issues

09-13-2009, 10:32 PM
I ran a leak down test on the cylinder was 20% leakage so it's pretty good.
I checked lash on the valves again one of them was off by .01 didn't make much difference.
I adjusted the governor that seemed to help a little but i'm still not able to throttle up or start with the choke on.
I checked and cleaned the plug again set to .30

tomorrow i'll get a spark tester and try and put up video that may help you guys see what it's doing

Thanks for you help

09-13-2009, 11:23 PM


09-14-2009, 07:15 AM
Can you post the spec number off this engine ?

09-15-2009, 09:52 PM
its a fc420v - gs14 - 01

09-15-2009, 11:15 PM
The port in question is a blind port that leads nowhere.

Here is your carb, Did you remove all parts in red then blow through all of the ports ?


#7 pilot jet has a small hole in the very tip, A bristle from a hand wire brush works well to assure it's fully open.

09-16-2009, 08:33 PM
i took everything apart used carb cleaner and a blow gun. I was reading some motor cycle forums last night guys were complaining about the needle valve not seating properly i'm going to try testing the valve and will post my results

09-16-2009, 09:18 PM
missed your comment about the #7 pilot i'll try that as well. I rechecked the float no fuel in side. i also checked the needle seems to be seating. The way i checked was by flipping the carb over and blowing in the gas line i lifted the float a few times to ensure air would pass and stop.

09-16-2009, 10:26 PM
cleaned out the #7 no junk left over

09-16-2009, 11:38 PM

In post 16 you mentioned getting a spark tester, Did you ?

Did you at any point remove the coil from the engine ?

If so, What did you set the coil to flywheel magnet air gap at ?

09-16-2009, 11:48 PM
my problems have shifted slightly i have cleaned the carb out but i'm having trouble identifying what to adjust. I got some info from here http://www.kawpower.com/ but the pdf kinda blows.

Can you folks help me identify what to adjust.


do any of the holes (if they are actual holes) on the front of this carb need to be open? They all have seem to have some RTV in em...just a straw to pull. I say you need to figure that coil out just to clear that possibility up.

09-17-2009, 10:08 PM
the holes covered in RTV appear to be there to help the gasket seat. they go nowhere. I'm still looking for a spark tester been a busy week going to hit some stores saturday.

coil is off the mower right now for some testing but i'm not great at using the multimeter so bringing it over to my brothers house this weekend for testing.

When i put the coil back on the air gap is .012

09-19-2009, 02:16 PM
i had some time so i threw it back together here is a video of the spark

and another of the machine at idle throttle closed, choke open. You can see as i throttle up it blows black smoke and dies.


09-19-2009, 06:48 PM

First, Make sure the choke isn't closing too soon when you throttle it up, There is a adjustment screw behind the cable control assembly to adjust when in the cable travel the choke starts to close.

Second, Put the dang air filter on it and try it again. A fixed main jet (non adjustable high speed) carb will not run a engine properly with the air filter off, The jet size required is determined with the air filter in place.

BTW, Good vids....

09-19-2009, 07:11 PM
the choke is not engaging too early but i'll put the air cleaner back on and give her a whirl.

09-20-2009, 09:46 PM
My brother came over tonight we got the machine to idle then he shut the fuel line almost closed limiting the amount of flow and we were able to get it to throttle up higher (3/4) with out bogging down and blowing black smoke.He is thinking something is going on with the carb it almost seems like the jetting is off.

09-21-2009, 10:05 AM

It's possible someone cleaned the main jet with a torch tip cleaner and reamed it larger, A higher than normal fuel level could cause the same issue.

Options; Replace the jet and double check the float and needle valve or replace or replace the whole carb and be done with it.....

09-21-2009, 08:47 PM
is it possible someone swapped another jet out or is that the only one that will fit?

In your experience am i better off buying a reman carb or buying the parts individually

here are the parts i need total is about 70 bucks i'm half way there with out shipping
float - 16031
return spring 92144A
air cleaner 11013a
needle valve 16030
gasket 11009c
main jet 49121
rubber gasket for idle jet 16038

09-21-2009, 09:46 PM
I looked back and you never posted the spec number off this engine, Two carbs I did look at showed only one main jet which was a #100......

70 bux without shipping..... Myself I'd have to spring for a NEW carb at around 140 bux and KNOW it will work properly.

I have ran across a few carbs that couldn't be cleaned to make run properly, So it's up to you if you want to take the $85 ? gamble......

Good Luck !

09-21-2009, 10:40 PM
is this what your looking for? fc420v - gs14 - 01

in my case when i gamble the house always wins. i'll price out some carbs thanks for your help Restrorob and to others that have contributed i will post my results

Nelson M Martin
09-22-2009, 08:31 AM
another thing to check:: its hard to be sure but it can happen that the carb wants to flood when engine is running.
carb wants to flood if the float does not shut off the fuel properly that is coming from the tank
Some carburetors have the overflow port in such a place where it can spill directly into the main port going into the motor head.
with vibration and the float/needle not shutting off it results in excess fuel causing black smoke

09-22-2009, 09:04 PM
so you thinking this may be a float issue? i'll try playing around with it tonight.

09-24-2009, 07:37 PM
the float seems to be in the right position and bending the tab did not seem to make much of a difference it also seemed to move back to it's original position.

09-26-2009, 02:58 PM
Someone gave me a great idea of how to eliminate the carb. He advised me to stop the fuel source drain the carb and stray carb cleaner or some combustible into the carb for a full throttle start. What do you guys think?

I figured i'll start of with starting fluid just cause i know that worked in the past. Sprayed some into the open carb and nothing just a few puffs. So i sprayed some on the foam element like i did before and popped on the air cleaner cover still nothing but a few puffs. So i pulled the plug which is wet and black. After cleaning and regapping the plug i sprayed more starting fluid into the air cleaner assembly. This time it back fired and the air cleaner assembly started on fire. I turned off the key and pulled the mower over until the vapors were pulled from the engine.

09-26-2009, 08:26 PM
This time it back fired and the air cleaner assembly started on fire.

http://www.xtremesystems.org/forums/images/smilies/rofl2.gif ...... Sorry...... I would have replied sooner but I had to clean Coke off my keyboard..... :cry:

Have you figured out what it's gonna take to make this engine run right yet ?

09-26-2009, 09:42 PM
Glad i could add a little humor to your day. Although i prefer people of walmart. I tested the spark tonight was able to throw a good blue spark up to .50 @ .55 it won't jump any more. tomorrow i'm going to check the crank key. I have located a compression tester.

09-27-2009, 02:49 PM
good and bad news it's not the key in the crank and i'm really surprised my bostich pancake compressor ran my 1/2 impact


09-28-2009, 12:13 AM
ran a compression check 40 psi and leakage was pretty fast. I need to check to see if i created the problem when i adjusted the valves or if it was like that.

09-28-2009, 07:01 AM
You need to check that compression gauge, It shouldn't show any leakage. If it did the shrader valve isn't holding and will give a false reading.

09-28-2009, 03:50 PM
rob thanks for the tip it's hard to ensure a good seal since the plug is recessed so far back. I'll try my push mower to see if its a seal or schrader valve issue

09-29-2009, 09:49 PM
confirmed there was an issue with compression tester i'm getting a steady reading of 40 which is way low manual states minimum of 71 psi. So next step is to find ouf if it's a valve or ring.

09-29-2009, 10:33 PM
I find it hard to believe this engine would even start on 40lbs much less run, Did you try this tester in a known good engine ?

09-30-2009, 01:30 PM
plugged the tester into my 5hp brigs push mower that one is registering 70 psi

09-30-2009, 02:46 PM
I hooked air up to the engine today to try and figure out where i'm loosing compression. Problem is when i pull the engine to tdc i'm having a hard time keeping the engine in that position to diagnose weather its a valve or ring issue. How do you guys do this?

09-30-2009, 06:14 PM
How do you guys do this?

Any way possible...... Rotate the engine so the piston is just a hair before TDC, Put a breaker bar with socket on the flywheel nut. Use a cheater pipe if needed so it hits on the left hand side (standing at the handlebars) of the frame where the fuel tank is mounted.

BTW, When you did this comp. test did you set the throttle to wide open position with the choke open ?

09-30-2009, 06:41 PM
great idea i have a 2 footer i can use thanks for the tip i'll give it a whirl.

Wow 1200 views this site must get a ton of traffic

10-01-2009, 10:18 PM
i had another thought this morning when i should have been working. what if i loosen the valves and rerun the compression test.

I did this and was able to achieve 90 psi and found out why the acr was included with this engine good news right. So that would suggest i messed up when i set lash on the valves right? Well i rotated the engine back to tdc and set the lash again confident i found one issue. I reran the compression test 40 psi again? :confused: I pulled out the tester rotated to tdc and checked lash my .006 feeler goes in snug what am i doing wrong????

10-01-2009, 11:10 PM
Are you sure your on compression stroke ?

You can check the ACR as below;


10-02-2009, 06:43 PM
i changed the lask from .006 to .012 and the compression jumped from 40 to 58psi have you ever heard of that?

10-02-2009, 08:10 PM
Well..... Yeah, By opening the lash you eliminated the compression release which will raise the compression because it's no longer functioning.

Did you check it as above ?

10-03-2009, 01:55 PM
acr seems to open more than .024 looks like somewhere in the .035 range but its hard to measure with out a dial indicator

10-03-2009, 02:12 PM
correction to previous post

acr seems to open more than .024 looks like somewhere in the .0625 range but its hard to measure with out a dial indicator i used a small ruler and seems like it moved 1/16 of an inch

10-04-2009, 10:51 PM
did some cleaning and some wire inspection today and noticed one of the wires were shrink wrapped the rest had that nice braided stuff around it. After cutting the shrink wrap off i found that there was about 1/2 inch of exposed wire on both wires leading to the charging coil they were touching. I wrapped up the wire eager to put the engine back together however it seems this may have been causing some issues but doesn't appear to be the complete issue. I am now able to get it to pop a few times with the choke on but still won't start normal. Tried the closed throttle trick like before but she popped through the carb. Could be because i had the air box off like Restrorob said.

10-06-2009, 09:17 PM
from the manual here is a picture of the control unit but i'm having a hard time finding it on the mower.

can someone help me match the two


10-06-2009, 09:55 PM
i'm having a hard time finding it on the mower.

Hmmm..... Maybe because your engine doesn't use a control module ?

Not all FC420's used a control module,

If the link you posted is in fact your engine spec number your looking for something that doesn't apply to your engine.

10-08-2009, 11:16 PM
Pulled the head off tonight. Piston, cylinder and valves all look pretty good. Can't see the cross hatch in the cylinder anymore but what do you expect for an 8 year old engine. I was able to remove the intake valve, seat does not move and valve has a nice even line around it where it mates with the seat. I'll get a hold of a spring compressor tomorrow and pull the exhaust valve.

10-10-2009, 03:07 PM
as you can see there is significant deposits in the exhaust port and on the exhaust valve. Both valves appear to have a nice seal mark on them. Neither of the seats are loose.


10-16-2009, 11:29 PM
after cleaning the carbon deposits from exhaust valve i resembled the head and took it to an engine shop where they vacuum tested the the seals. Intake was good the exhaust needed some grinding had some minor pitting after they both sealed great. Just need to get a head gasket then she'll go back together.