Valve issues on a Honda engine

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.
Status
Not open for further replies.

infinitymike

Minister of Fire
Aug 23, 2011
1,835
Long Island, NY
I was running my splitter the other day .
It has a Honda GX 390
image-jpg.117170

I shut it down and about 10 minutes later I started it up.
It was running real rough. It sounded mufflely or farty.
I shut it down and restarted it, same thing.
Since I have had it, when I try to start it , the compression can be hard and the pull cord can get ripped out of my hand every now now then.
Now it was even harder to pull and the cord ripped back with even more force.
I was no longer able to start it and eventually broke the rip cord.

I opened up the valve cover and this is what I found.


image-jpg.117168


I also found this and assumed it goes on the end of the spring since it fit so well


image-jpg.117169


I took both rocker arms off and pulled the push rods out,they were fine.

image-jpg.117172


I put it back together but didn't gap the rockers.
It still sounds weird when I pull the cord and I still can't start it and the compression is way hard.



Other than adjusting the rockers, what could be wrong.
Also what should I adjust the rockers to?

Should I pull the head? Could I have bent a valve?
 
did you try it without the spark plug?

Yes. It pulls easy but something just doesn't sound right. It doesn't have that nice purr when you pull an engine over without the plugs.
 
Hopefully you can see them know.


This is what I found when I opened the cover
image.jpg




This is the little cap that seemed to belong on the end of the rod holding the spring.
image.jpg



Both rockers off and the little cap on the left spring.
image.jpg
 

Attachments

  • image.jpg
    image.jpg
    274.7 KB · Views: 2,213
I can't see the pictures but will assume the valve spring keepers came off and bent the valve from a piston to valve head collision. If the exhaust valve was bent, then you should have some popping through the intake/carb and if it is the intake valve that's bent you should lose compression. If you lost one of the valve heads or broke the piston, the pieces could be preventing you from pulling the engine over 360 degrees. Does the engine spin over by hand if you turn the flywheel/pull cord spool piece? This again is all an assumption and worst case scenario-hopefully it is not!
 
I can view the pictures now, thanks. Yes that goes on the tip of the valve and it looks like the valve keeper stayed in place. Judging from the pictures, it almost looks like the valve adjuster/jam nut loosened up or the threads stripped out-hard to see. Can you confirm? If there is too much valve lash caused by above, that cap could come off/rocker arm could roll off to the side. I've also seen the exhaust valve seat separate from the head causing similar issues.
 
do you have a compression tester? a leak down and compression test will tell you a lot in this situation. harbor freight had them I believe.
 
Once you figure out what all went wrong, there are videos on youtube about adjusting the valves on a Honda GX.

 
I can view the pictures now, thanks. Yes that goes on the tip of the valve and it looks like the valve keeper stayed in place. Judging from the pictures, it almost looks like the valve adjuster/jam nut loosened up or the threads stripped out-hard to see. Can you confirm? If there is too much valve lash caused by above, that cap could come off/rocker arm could roll off to the side. I've also seen the exhaust valve seat separate from the head causing similar issues.
The studs are fine and not stripped out.
I am able to tighten both nuts.
With the plug out it pulls very easy. But with the plug in its hard and is kinda back fires out of the carb but doesn't start. So that sounds like a bent exhaust valve. Ok I guess I'm pulling the head. :(
 
I tried adjusting the rocker arms but that didn't work.
So I finally pulled the head and this is what I found.
The seat for the valve has popped out. The head is shot.

head.JPG


Now I can buy a new Honda OEM head with everything...valves, springs, push rods, etc, etc. A complete assembly.
That will run me about....$450.00 +/-
http://www.hondaenginepartstore.com...NDER_HEAD/GX390K1-JPN-ED6/2410ZF60DZF60E0200D

Or I can buy an after market one for about...$70.00 from this place http://www.hlsproparts.com/product-p/h30341.htm

or $100. from this place http://www.ebay.com/itm/Honda-Cylinder-Head-Assembly-Replaces-13hp-GX390-Engine-/260631074863

OR I can buy a BRAND NEW ENGINE for about $600 from here http://www.ebay.com/itm/Honda-GX390-13-HP-Horizontal-Shaft-Engine-NEW-/330941730466

What would you do????
 
Not knowing anything else about the motor, hours on motor, if it was mine I would go with the $100 head and gasket kit. I would be taking a close look at the piston and cylinder for any sign of damage. Carb and intake would be inspected also. If the rest of the splitter was working great then $100 is a small price to pay to get it running again. Then maybe budget for a new one and sell the old one. Just a thought.
 
Not knowing anything else about the motor, hours on motor, if it was mine I would go with the $100 head and gasket kit. I would be taking a close look at the piston and cylinder for any sign of damage. Carb and intake would be inspected also. If the rest of the splitter was working great then $100 is a small price to pay to get it running again. Then maybe budget for a new one and sell the old one. Just a thought.


A friend and I bought it together from a commercial firewood company. It's a Timberwolf TW5. A real animal!
It has a lot of hours on it. I'm sure.
When you split the cost between the two of us, from the original purchase and some other repairs, we are into it for about $900 each.
The ram piston is rebuilt, the valves are rebuilt, the pump looks good, the wedge was re-welded, the log lifter is strong as can be.

My friend is leaning towards a new motor, but I'm saying just buy the head.
I guess if we bought a new motor we know we will get a lifetime out of it.
 
I am not an authority, but looking at the inside of the case, that looks like a pretty high hour unit with less than optimal maintenance. The amount of hours of operation required to wear out a wedge on a splitter like that is probably REALLY long or it could have been abused.

I would think a new engine would last two homeowners over 20 years.
 
I am not an authority, but looking at the inside of the case, that looks like a pretty high hour unit with less than optimal maintenance. The amount of hours of operation required to wear out a wedge on a splitter like that is probably REALLY long or it could have been abused.

I would think a new engine would last two homeowners over 20 years.

The splitter is about 20 years old but the previous owner has replaced almost everything through out the years.
I can't get my head inbetween the motor and ibeam to see how old the engine is. But I'm sure it's got plenty of hours on it.

I actually tore the wedge off the beam
It did have hairline cracks in the welds and I just did it in.
That was a big ticket since I had to bring it to professional to get welded. $500 <>
Like I said we paid $1000 original and dumped another $800. So another $600 would bring us to $1200 each. Brand new theses things run $8000

I've already split close to 25 cord since we bought it. That's $36 a cord.
If we buy the motor then it would be $48 a cord. Still not bad.

He has split about 18 cord also.
 
I guess splitting the cost of a new motor with your partner makes alot of sense. I personally would make the old motor a runner and put it up for sale. After the new motor, it sounds like there's not much left to replace or repair on that splitter,
 
if you look around the net, you can find ways to determine the internal welfare of it. bore wear, piston wear things like that will tell you if it's worth rebuilding or not. personally I would bore it an build it, but that's just how I am.
 
if you look around the net, you can find ways to determine the internal welfare of it. bore wear, piston wear things like that will tell you if it's worth rebuilding or not. personally I would bore it an build it, but that's just how I am.

Based on your avatar, I can see why you would do that :)
 
I have not been too impressed with the new GX390s I have had 2 new ones with cam & decompressor come apart on them. It will rip the starter cord out of your hands or break the handle off when you try starting them. Not to mention what it does to your shoulder & hands when it does it.
It may be worth checking Harbor freight for a new motor, new Hondas are made in China anyway.
 
I have not been too impressed with the new GX390s I have had 2 new ones with cam & decompressor come apart on them. It will rip the starter cord out of your hands or break the handle off when you try starting them. Not to mention what it does to your shoulder & hands when it does it.
It may be worth checking Harbor freight for a new motor, new Hondas are made in China anyway.


That was what was happening to me on occasion. The rip cord would rip right out of my hand if I didn't catch it on the right compression stroke. maybe it was because the exhaust valve wasn't opening correctly.
 
Assuming the bottom end is in decent shape go for the after market head. Bolt it on and get back to work! Gotta feed the beast ;).
 
Bolt it on and get back to work! Gotta feed the beast ;).

I hear ya. I've gained 5lbs from feeding the beast and not being out there and working.
 
Status
Not open for further replies.