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Punisher3S
06-06-2005, 05:46 PM
Hi guys.. what a way to start my new job today as a mechanic at a landscaping company...

There is an edge trimmer there.. I can't remember the name of it for the life of me.. but anyway it has a Kawasaki FC420V 14HP motor on it.

What happened (from what I was told) The edger is front heavy because of the motor and it was tipped forward and laid like that for a few hours.. I was told that this 'filled' the cylinder with oil or something.. The oil wreaked of gas.. They said the fix for it was to drain the oil out and make sure it's all ok and it should start and run fine then.

Well I drained oil.. replaced filter.. refilled the crankcase.. go to start it.. nothing.. got a few carb back fires saw a spark jump out of the carb a few times but that was it... After that you just pull and pull and pull nothing.. SO I put a compression tester on and yanked.. Needle would jump and then drop back to zero.. No compression.. no wonder it won't start!

So I rip the valve cover off and go to town.. notice that the exhaust valve for some reason is being pushed open slightly when the piston comes up for compression.. letting the compression out.. wtf... So I set the piston to TDC on the compression stroke.. Guestimate a good valve clearance (since I don't have any factory specs on it and no Kawasaki spec book for this motor) and I put it all back together.. leave the valve cover off though.. Yank the cord and UGGGGHHHH.. cable snaps out of my hand..

So I try it again this time slower.. everytime it comes up for compression.. you CANNOT pull the cord.. just won't budge!

For some damn reason the camshaft was pushing the pushrod out and making the exhaust valve open slightly .. which I already went over... EVEN AFTER I set the valve clearance!

I'm lost and confused on this one.. with out ripping the motor apart.. I'd like to impress the boss.. so if anyone has any clue as to WHAT THE HELL is going on I'd really appreciate some help!

Also, I'm going to try another google search to find engine specifications but if anyone has them bookmarked or something please post the link, thanks!

Restrorob
06-06-2005, 08:01 PM
The movement in the exhaust valve when the piston comes up to compression stroke is the compression release thats on the camshaft,The engine won't spin over because you have the valves adjusted too loose which will not let this function correctly,Make sure the piston is on TDC compression stroke and adjust valves to factory specs. (sorry I don't have them on hand). It probably wouldn't start after the oil change because the cylinder was still full of fuel thus flooded.
As for your compression gauge check the shrader valve in the end,It probably has a piece of trash in it holding it open.

Punisher3S
06-06-2005, 09:43 PM
I appreciate it.. That's all very weird though.. Compression release.. heh.. But now the question still lingers.. why wouldn't it start before I started working on the valves....

Spark is there.. fuel is getting to the carburetor.. about the only thing I could've figured was that the exhaust valve was opening during the compression stroke.. that's the weirdest fricken thing ever.. I've worked on other small motors.. specificaly a Honda propane 13HP motor and I adjusted valve lash on that and didn't ever see anything like a compression release with the exhaust valve...

Is it something that only happens during cranking so it's easier?

Restrorob
06-06-2005, 10:21 PM
I appreciate it.. That's all very weird though.. Compression release.. heh.. But now the question still lingers.. why wouldn't it start before I started working on the valves....

Spark is there.. fuel is getting to the carburetor.. about the only thing I could've figured was that the exhaust valve was opening during the compression stroke.. that's the weirdest fricken thing ever.. I've worked on other small motors.. specificaly a Honda propane 13HP motor and I adjusted valve lash on that and didn't ever see anything like a compression release with the exhaust valve...

Is it something that only happens during cranking so it's easier?

Yes it only operates during cranking so the engine will spin over easier.
If you re-read my first post closer you mite see the answer to your lingering question !

Punisher3S
06-07-2005, 12:04 AM
The movement in the exhaust valve when the piston comes up to compression stroke is the compression release thats on the camshaft,The engine won't spin over because you have the valves adjusted too loose which will not let this function correctly,Make sure the piston is on TDC compression stroke and adjust valves to factory specs. (sorry I don't have them on hand). It probably wouldn't start after the oil change because the cylinder was still full of fuel thus flooded.
As for your compression gauge check the shrader valve in the end,It probably has a piece of trash in it holding it open.


Well.. how do you suggest I get the fuel out? Other than letting the cylinder air out VIA removing the spark plug.. That's the only way I can think of.

I'll re-adjust the valves..

If it still; doesn't start.. what would you suggest then?

txlawnking
06-07-2005, 02:08 AM
I believe the lash is .005".. Also remember this when setting valves: Intake valve closing, set exhaust. Exhaust opening, set intake. Works on everything from Formula one, to a Mack truck.

I'm presuming that the engine turns over easily with the plug removed, and is no longer Hydro locked, as that is likely what caused this problem in the first place. Check for physical damage to other components..Bent rod, sheared flywheel key, etc. But only after you've eliminated the obvious stuff first.

Just remember the diagnostic flow chart for spark ignition engines:

1 check spark, and for proper timing

2 check for proper fuel delivery

3 check compression.

Restrorob
06-07-2005, 07:53 AM
Well.. how do you suggest I get the fuel out? Other than letting the cylinder air out VIA removing the spark plug.. That's the only way I can think of.

I'll re-adjust the valves..

If it still; doesn't start.. what would you suggest then?


Blow the cylinder out with compressed air,And use the chart that txlawnking posted.
But this engine isn't a racer or mack,The piston must be on TDC compression stroke with both valves closed for proper adjustment due to the compression release on the cam that the racer or mack doesn't have.

Punisher3S
06-07-2005, 05:22 PM
Well.. Came in this morning.. talked to boss.. he said he fixed it last night.. said I have the valve lash to tight.. Uh.. That's just the way I left it yesterday.. since I set the valve lash pretty close to what I thought it would be.. just a tiny tiny bit of play between rocker and valve and it still wouldn't start.. just would NOT start yesterday no matter what I did.. so I don't know.. He set the valves to .009"

Which I don't know.. Intake valve clearance is smaller than exhaust.. but hell it runs I don't care.. lol

Just weird that I couldn't get it started yesterday for nothing.. Maybe he did somethin else other than set valve lash.. maybe he blew the cylinder out too.. who knows.

CCWKen
06-08-2005, 02:26 AM
The compression relief design in the cam is a common item on small engines. As Rob states, it makes the engine easier to crank on startup. After the engine starts, the compression relief is so small and short the effect is negligible at higher rpms. In fact, it adds to the power curve and engine cooling.

If you plan to be a "mechanic" on small engines, I suggest you get a few books and bone up on small engines and engine design. The compression relief design/idea has been in use on small engines since at least the 60's and in some larger engines since the 20's. And setting critical clearances without specs or by the seat of your pants will not only shorten the life of the engines but also your career as a mechanic.

YardPro
06-08-2005, 07:37 AM
not to be a jerk, but how are tou a mechanic for a company and don't know anything about repair?????

Restrorob
06-08-2005, 08:07 AM
The compression relief design in the cam is a common item on small engines. As Rob states, it makes the engine easier to crank on startup. After the engine starts, the compression relief is so small and short the effect is negligible at higher rpms. In fact, it adds to the power curve and engine cooling.

If you plan to be a "mechanic" on small engines, I suggest you get a few books and bone up on small engines and engine design. The compression relief design/idea has been in use on small engines since at least the 60's and in some larger engines since the 20's. And setting critical clearances without specs or by the seat of your pants will not only shorten the life of the engines but also your career as a mechanic.

Could'nt have said it any better myself Ken,I started in this feild after 12yrs. as a Auto Service Technician and never owned much less worked on a lawn mower before.My first day on the job was about the same,doing no brainer things.So I started bringing the shop service manuals home and reading up !!!
Today I'm still at the same place after 14yrs. and Shop Foreman,As you can see by my credits reading the manuals has gotten me where I am today!!! payup