Author Topic: Changfa 22hp 1115 engine decompression lever not working?  (Read 442 times)

jeff

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Changfa 22hp 1115 engine decompression lever not working?
« on: August 25, 2021, 08:17:58 PM »
Hello,

I have a genset I built a few years back, changfa 1115 with a 10kw head. Had it running during a power outage, ran great for 3 days without issues. Fast forward a couple of years without running it nor starting it, was stored undercover and looks no worse for wear. Decided to bring it into my shop and see if I could hand crank it as I did before, no-go.

I engaged the decompression lever as before, tried to spin the flywheel and couldnít get past the compression stroke, tried a few times but no luck. Took of the valve cover, inspected what little is inside for the decompression mechanisms, just an oblong knob of sorts, outside lever moved as before. While cover was off I took the end of a rubber mallet and pressed the intake valve open, turned flywheel with hand crank and it moved past the compression stroke, no stuck valves. Hum? Decide to see if I could see if the internal decompression knob was engaging the intake valve stem, I applied a lite coat of anti-seize compound on end of valve stem, cleaned the decompression knob of any oil, assembled valve cover back on, engaged the decompression lever and hit the button to use the starter to turn the engine over a few time, pulled the cover and no transfer of anti-seize compound to the internal decompression knob, not hitting it at all?

It worked before using the hand crank and the decompression lever, but not now. Any ideas?

Also trying to see if I need to adjust the valve clearances but canít find the TDC marking anywhere on the flywheel? Again, any ideas where this marking is, externally?

Attached are a few pics of the inside of valve cover showing the know in question as well as the valve body.

Thanks
Jeff

jeff

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Re: Changfa 22hp 1115 engine decompression lever not working?
« Reply #1 on: August 25, 2021, 08:19:57 PM »
Forgot to add other pic attachment

veggie

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Re: Changfa 22hp 1115 engine decompression lever not working?
« Reply #2 on: August 26, 2021, 02:40:03 PM »
Here's a theory ...

If I am looking a the correct valve, the marks indicate that the de-comp lever is only contacting the edge of the rocker pad.
Being that the valve cover is held in place by a single stud in the center, the cover can be rotated somewhat to the left or right once installed.
Is it possible that the valve cover is being installed slightly rotated enough to make the actuator completely miss the rocker?

Also try holding the valve cover slightly rotated CW when installing. Then try again holding it slightly CCW.

See where I marked on the picture below....

just a thought,
Veggie

« Last Edit: August 26, 2021, 02:42:21 PM by veggie »
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jeff

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Re: Changfa 22hp 1115 engine decompression lever not working?
« Reply #3 on: August 26, 2021, 03:32:15 PM »
I decided to see if I could resolve my decompression lever not working like it had been before. I pulled the push rods and noticed the exhaust push rod is bent, see attached picture, this canít be a normal? Could I just see if I can straighten it, donít know where I could get another one.

This to me doesnít seem like it would cause my decompression lever from working since the lever engages the intake rocker arm, either way, it donít look normal to me. What say you?

The one on the right is the exhaust push rod. The intake is straight.

jeff

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Re: Changfa 22hp 1115 engine decompression lever not working?
« Reply #4 on: August 26, 2021, 04:46:57 PM »
Here's a theory ...

If I am looking a the correct valve, the marks indicate that the de-comp lever is only contacting the edge of the rocker pad.
Being that the valve cover is held in place by a single stud in the center, the cover can be rotated somewhat to the left or right once installed.
Is it possible that the valve cover is being installed slightly rotated enough to make the actuator completely miss the rocker?

Also try holding the valve cover slightly rotated CW when installing. Then try again holding it slightly CCW.

See where I marked on the picture below....

just a thought,
Veggie


Thanks for the response, make sense but the cover can’t be skewed cw nor ccw since there is a location pin in between the two valve, you can see it in the picture, it aligns the cover with no wiggle room to rotate either direction. I don’t thing the decompression knob inside can be moved left or right, will take apart again and see if I can shift it left or right to better hit the valve stem more in the center.

Did you see my other pic I uploaded, the one where the exhaust push rod is bent? Don’t know if I need to tear into engine to find the cause of this, omg! Not sure how this happened and the why it did? The last time I ran the genset, had no issues? Was this like this from factory, only have about 40 hrs on it.


Also the marks you see on the intake valve stem, that was from before, since then I applied some anti-seize compound on valve stem and engaged the decompression lever and nothing was transfer to decompression knob.

Thanks again for piping in! Appreciate the help! Lol

Good day
« Last Edit: August 26, 2021, 04:51:29 PM by jeff »

veggie

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Re: Changfa 22hp 1115 engine decompression lever not working?
« Reply #5 on: August 26, 2021, 05:51:37 PM »

When you pull the decompression lever (with everything assembled) do you feel the resistance of the valve spring? or does it just flap without any resistance?
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mobile_bob

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Re: Changfa 22hp 1115 engine decompression lever not working?
« Reply #6 on: August 26, 2021, 06:19:25 PM »
from what i read, correct me if i am wrong

1. you first tried to crank the engine over, but it would not go past top dead center?

2. you removed the valve cover, used a rubber mallet to move the valves to see if they were stuck?

3. you found a bent pushrod?

if all this is true, this is what i suspect

when you parked the engine, you did not roll it over to compression stroke, this would have left the cylinder closed, with the valves both closed, moisture would have a harder time getting in.

i think it was parked in such a way that moisture/water got in and stuck the exhaust valve in an open position, then when you tried to turn the engine over, the piston contacted the exhaust valve, which was stuck tight enough that with more force used to crank the engine something had to give, that being the pushrod, which ended up bent.

now if it were me

1. i would remove the rocker assy
2. i would use a dead blow hammer, to work the valves up and down, and i would remove the manifolds to i could squirt some oil on the stems on the bottom of the guides and also from the top.  making sure they open and close freely (the piston needs to be toward the bottom of the cylinder.
3. i would use a hammer and a suitable anvil and hammer the bent pushrod straight again... it will be fine.
4. then reassemble, and rotate the engine such that one of the valves is opened, and squirt a little oil into the cylinder past the open valve, just a few squirts.
5. put the manifolds back on, reset the valves.  set the intake with the exhaust open, and visa versa.
6. put the valve cover on, check the  comp release function, and set it open, rotate the engine several revolutions, and if all is good

crank it up again!

my bet is some water got into one of the manifolds, moisture/humidity, and stuck the valve.

get it freed up and it should live again.

it is possible that the exhaust valve got bent, but i think you might get lucky and that not be the case.

worst case scenario

you get to pull the head and do a valve job.

bob g
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(useful forums), utterpower.com for all sorts of diy info

jeff

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Re: Changfa 22hp 1115 engine decompression lever not working?
« Reply #7 on: August 26, 2021, 06:31:21 PM »

When you pull the decompression lever (with everything assembled) do you feel the resistance of the valve spring? or does it just flap without any resistance?

It doesnít feel like it is hitting the valve stem at all, there is the resistance to the return spring on the outside, I apples some antiSeize compound on the internal valve stem, nothing got transferred to the decompression knob inside, I did rotate the flywheel but was difficult to get past the compression stroke.

Thanks so much for you input.

Jeffrey

veggie

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Re: Changfa 22hp 1115 engine decompression lever not working?
« Reply #8 on: August 26, 2021, 07:19:46 PM »
Ok, so your lever is not contacting the valve rocker. That's the issue.
Was there a part on the inside of that actuator that fell off?  A part that fits over that flat spot on the actuator and reaches the rocker?

You win this week's award for the strangest mystery in the entire universe !   ???
« Last Edit: August 26, 2021, 07:25:14 PM by veggie »
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veggie

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Re: Changfa 22hp 1115 engine decompression lever not working?
« Reply #9 on: August 26, 2021, 07:24:39 PM »
... and why is the rod bent?
Did the missing piece fall down and briefly jam the valve rocker right where the pushrod contacts the rocker?
Check all around the floor where you first removed the valve cover.

If you have the manual that came with the engine, check to see if there is a lever that is supposed to fit onto that decompression stub shaft.
My Changfa's came with an exploded view parts list (in Chinese of course). Although mine is a different model so it does not apply to your monster 1115
« Last Edit: August 26, 2021, 07:28:27 PM by veggie »
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jeff

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Re: Changfa 22hp 1115 engine decompression lever not working?
« Reply #10 on: August 26, 2021, 11:08:31 PM »
Mobile_Bob,

Well written!

I did not doing any of the things when parking the engine. Later this week I was reading the manual and remember seeing something about what you just said.

While the valve cover was removed, using the end of a rubber mallet I pressed both valves and they did move, so they must not of been stuck badly  I did put the starter to use after trying to turn by hand, so this is probably when the push rod got bent, Maybe did that a few times than stopped and realized something was amiss since I could turn by hand before the long parking of the genset.

I will do as you suggested and squirt some oil in each intake/exhaust.

Next question, where do I determine the DTC, is there some marking on the flywheel somewhere? Or do I need to pull the side cover and look for timing marks on the cam?

Many thanks for a well thought out plan of action, awesome, it makes sense now!

Thanks again!

mobile_bob

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Re: Changfa 22hp 1115 engine decompression lever not working?
« Reply #11 on: August 26, 2021, 11:41:16 PM »
look on the outer edge of the flywheel, along side the ring gear
the marks will be covered in paint as they are not very deeply stamped by the factory.

why do you need the tdc marks?

only reason to use them in my opinion is if you are setting fuel timing.

bob g
otherpower.com, microcogen.info, practicalmachinist.com
(useful forums), utterpower.com for all sorts of diy info

jeff

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Re: Changfa 22hp 1115 engine decompression lever not working?
« Reply #12 on: August 27, 2021, 12:58:22 AM »
look on the outer edge of the flywheel, along side the ring gear
the marks will be covered in paint as they are not very deeply stamped by the factory.

why do you need the tdc marks?

only reason to use them in my opinion is if you are setting fuel timing.

bob g


Bob,

I loosened the rocker arms to remove the push rods, need to be able to readjust them with feeler gauge. Not a mechanic by any means but understand most things with some guidance from others, lol

Any helpful guides for adjusting them properly? I did read the manual and got the values for each valve. Just donít know the proper sequence for doing that.

Many thanks Bob.

mobile_bob

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Re: Changfa 22hp 1115 engine decompression lever not working?
« Reply #13 on: August 27, 2021, 01:09:19 AM »
its pretty easy to do
all you need to do is roll the engine over until the exhaust valve is well on its way open, stop there and adjust the intake valve

then roll it over until the intake is well on its way open and adjust the exhaust valve.

and you will be good to go.

the manual will have the settings, and i think the spares kit even has the feeler gauge to set them with...

btw, the intake uses the thinner gauge, and exhaust the thicker one.

adjust with the feeler under the rocker and on top of the valve stem, what you want is after you tighten the lock nut there is just a little drag to remove the feeler gauge. if it is too tight it will be hard to pull out, too loose and it slips right out.

these things are not critical on these engines, you can be off a couple thousands and still be ok.

best done with a warm engine, so if you do it cold just set them so the feeler is on the loose side and you will be good.


bob g
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(useful forums), utterpower.com for all sorts of diy info

jeff

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Re: Changfa 22hp 1115 engine decompression lever not working?
« Reply #14 on: August 27, 2021, 06:13:34 PM »
Bob and veggie,

I want to thank both of you for your valuable information, you helped me in a tremendous way!

I removed the valve cover again, took out the push rods, inspected everything I could. I took a acid brush and applies some light oil the the valve stems inside the head and with the end of my rubber mallet started to work the valve in/out numerous times. Reinstalled the push rods, found the feeler gauge that came with my spare parts kit  and proceeded to adjust them. I applied some anti-seize compound to the end of the intake valve stem, reassembled the valve cover, turned the hand crank while holding the decompression lever and I felt resistant, I could feel it pressing on the valve stem, removed the valve cover again and seen that the anti-seize compound had transferred to the decompression knob.

Previously I had straightened out the exhaust push rod, came out pretty straight, not 100% but I settled for 97%, close enough for me.

Everything is looking good so far, havenít  started it yet, had some nasty looking fuel, so I drained the fuel from the filters and got some fresh fuel ready to start this beast up again. Might have air in the system, donít know for sure how to purge the fuel system properly , I know that this can cause danger to ones hands and fingers if opening high pressure line while trying to purge system. Just what Iíve heard. Not sure which line I need to crack open and in which order. So if any of you know the safe procedure to proceed purging air from the system, it would be most welcomed information since starting this thread.

Iím going to have to get in the habit of starting this thing more frequently.

Thanks again fellasÖ

Jeffrey