Honda GCV160 No Start

[hppants]

Greetings:

(I searched before I posted)

Honda GCV160 motor won't start. I'm not a mechanical genius, but I've "turned wrenches" for a long time. This is what I've done/know:

1. Won't run on carb fluid or starting fluid.
2. Cleaned carb thoroughly (trust me, that ain't it)
3. has what I consider to be good strong fire at spark plug.
4. Motor has no compression using tester.
5. Pulled cam cover, ZERO valve clearance on exhaust valve (compression release working?) About 0.006" on intake.
6. Can't find timing marks or instructions on how to check time, check flywheel key.

Motor is on a 3 year old pressure washer that otherwise is perfect for me. I'd appreciate any advice you can offer.

 

[Chris Parman]

Hello hppants: Set the valve lash to the following.

Intake valve lash: (0.006 +/- .002 inch)
Exhaust valve lash: (0.008 +/- .002 inch)

Then perform another compression test and report back. Here is a procedure to follow as well.

 

[hppants]

I'm cross posting information to this thread from another - in the hopes of getting help.

Is it possible that the exhaust valve "adjusted itself" to zero clearance? I've never heard of that happening on a "screw and nut" style of valve train. NO ONE has been into this motor (I bought it new) before.

Exhaust has ZERO clearance now.

Looking at it from the top (flywheel), the cam pully has the decompression "rod" in the right most position in the slot. I can easily slide it to the left, and if I let it go, it will slide (very slowly) on its own to the right. If I hold the rod in the left side of the slot, and turn the motor, I don't develop any clearnance in the exhaust valve. That is concerning to me. If the exhaust valve won't seat, I'll never get compression.

I haven't pulled the flywheel to see if the key is sheared.

(scratching my head)

Thoughts?

Thanks in advance.

 

[Honda Tech]

It's quite rare to find a sheared key on a Honda. I'm willing to bet that if you have zero clearance and zero compression, you actually have a broken valve. With the head of the valve broken off, the valve stem is spring loaded, so it will butt up against the rocker arm. Even if you adjust the tappet, you will find that you still have zero clearance. If so, most likely damaged the piston also. If you were able to replace the valve and piston yourself, it would be cost effective. If you have to take it to a servicing dealer, buy a new engine or pressure washer.

 

[hppants]

Interesting - seems that if the valve broke, wouldn't the valve be attempting to float around in the combustion chamber? I'm not hearing anything unusual - wish I had one of those "pen light cameras" to look in there.

Bent valve is sounding more likely. Or maybe a bent rocker arm. Maybe I could check that out.

On this video - at 4:29, this is the position my decompressor is in for my cam pulley. And clearly, this motor has clearance on the exhaust valve.

Doing a valve job (and potentially engine rebuild) is beyond my capability. I was willing to tackle changing the cam pulley, but that's about my limit, I think.

Disappointing - pressure washer was only a couple years old....

 

[Honda Tech]

If the head broke off of the valve, it is most likely imbedded into the top of the piston. If it wasn't, the engine would not rotate 360 degrees because there is not enough internal clearance.

 

[Honda Tech]

Interesting - seems that if the valve broke, wouldn't the valve be attempting to float around in the combustion chamber? I'm not hearing anything unusual - wish I had one of those "pen light cameras" to look in there.

Bent valve is sounding more likely. Or maybe a bent rocker arm. Maybe I could check that out.

On this video - at 4:29, this is the position my decompressor is in for my cam pulley. And clearly, this motor has clearance on the exhaust valve.

Doing a valve job (and potentially engine rebuild) is beyond my capability. I was willing to tackle changing the cam pulley, but that's about my limit, I think.

Disappointing - pressure washer was only a couple years old....

The Honda engine has a two year warranty. If it is still under 2 years (or very near it), you can get it warrantied.

 

[Chris Parman]

hppants: I foresee a GCV160 tear-down and rebuild in your future.

 

[hppants]

Spent some time with it yesterday. Turns out that the "zero clearance" issue I thought I had with the exhaust valve was really just me not having the piston at TDC and ensuring that the cam marks were lined up. When I did that, what I really had on the exhaust was HUGE clearance - like well over 0.040"!! I was able to adjust that, and while in there, I adjusted the intake just a smidge (it was only about 0.002" loose). Made no difference. No compression and no start (squirt of carb spray or otherwise). I don't think the excess exhaust clearance is affecting my issue - I might have a bad rocker, but the valve should still close and provide compression - right?

I pulled the gas tank and the "starter engager thingie" above the flywheel and confirmed that the key is in the keyway.

I also can now see how the decompressor mechanism works for on the cam pulley (ingenious) and that isn't bad.

I can push in both valves and they appear to move freely, but of course who knows if the valve is bent - I didn't do a leak down test.

So I suppose I'm down to either a bent valve, broken piston ring, or ....??????.

think it's beyond my ability now - first time I've ever had a honda motor (of any kind - car, SUV, small engine, etc.) fail.

 

[Honda Tech]

Bent valve would be very unlikely. If they get bent, they don't move. Broken piston and or ring...quite rare at best. Can you confirm that the piston is actually moving with the crankshaft? Since this is an overhead cam engine and the cam is connected to the crankshaft via a belt, it's likely that the connecting rod broke. If it pulls over super easy, broken rod. Doubt it would be worth repairing even if you were able.