Honda GCV160 Mower "kickback" when starting

[enzololajett]

I have a Honda HRR2169vya mower with a GCV160 engine. Lately it has started kicking back when I attempt to start it. It seems to be getting worse and nearly broke my arm earlier this week. Typically, I see this when the timing is off, possibly due to a slipped or broken flywheel key. I pulled the flywheel and the Woodruff key is perfect.

If I pull the spark plug the mower spins freely. If I pull it over a few times with no plug it will start easily, first pull when I replace the plug. If I shut it off it will immediately exhibit kick back. I can (so far) always get it started, but I now wear heavy gloves and must be very careful. It seems as though the mower is experiencing a sort of "hydro lock" rather than spark timing issue. With the wire pulled from the spark plug, I still get kick back.

I suspect a timing or valve lash issue as I'm pretty sure there's a timing belt for the cams and a lash adjustment that's critical. I'm hesitant to pull the cover as the mower still has a few months left on warranty. I don't want to void it by doing obvious do-it-yourself stuff that would probably be obvious if I had to re-glue the valve cover. There is no authorized Honda shop near to my home where I could get warranty help.

If I was 100% sure that my issue was something easily adjusted under the valve cover, I might just take a chance at a self repair even if it would void my warranty.

Anyone had similar issues with this engine? Any advice would be welcome.

 

[bertsmobile1]

I the engine just kicks back and the flywheel key is intact then the decompression is not working.

 

[robert@honda]

I don't want to void it by doing obvious do-it-yourself stuff that would probably be obvious if I had to re-glue the valve cover. There is no authorized Honda shop near to my home where I could get warranty help.

If I was 100% sure that my issue was something easily adjusted under the valve cover, I might just take a chance at a self repair even if it would void my warranty.

Anyone had similar issues with this engine? Any advice would be welcome.

You won't void your warranty if you attempt repairs. Now if your repairs cause other things to fail or break, those repairs would not be covered under warranty.

Now it sure sounds like a good old fashioned case of hydro lock due to engine oil getting into the cylinder. This can easily happen if you tip the mower on the wrong side (air cleaner side DOWN), as this allows oil to flow into the air cleaner/carb and into the cylinder. Trying pulling the spark plug out and give the engine some spins. Inspect the air cleaner / carb for any signs of oil intrusion.

If it is more involved (decompressor or other internal engine issues (slipped timing belt?) , get a shop manual to guide you through all the details...Honda sells paper copies on Amazon and eBay (free shipping):

Honda Power Equipment Shop Manuals on eBay
Honda Power Equipment Shop Manuals on Amazon

 

[enzololajett]

Thanks for the responses. As I mentioned in my original post, I've pulled the spark plug and noted that the engine spins freely. I can get it started and there is no indication of oil in the cylinder (exhaust is clean) when running. The engine has never been turned on its "left" side as I know this will allow oil to possibly foul the cylinder. If I run the engine, shut it off, and pull the starter within a few seconds, it will still kick. So, I'm pretty sure it is a mechanical problem with cam timing, or, more likely, a decompression system problem. I was hoping for help in correcting the decompression system problem, but I guess I'll pop for a copy of the shop manual.

It's my impression that the decompression system causes the intake valve to slightly open just before TDC at slow cranking speeds. Is there some way some part of the decompression system is "sticking" due to being dirty (sludge? carbon?), or can ethanol (E10) fuel cause any problems? Can improper valve lash add to the problem? Are parts of the decompression system accessible from inside the valve/cam cover, or is further disassembly required?

If anyone has successfully corrected problems with the decompression system I'd welcome any tips you have to offer. Thanks.

 

[robert@honda]

It's my impression that the decompression system causes the intake valve to slightly open just before TDC at slow cranking speeds. Is there some way some part of the decompression system is "sticking" due to being dirty (sludge? carbon?), or can ethanol (E10) fuel cause any problems? Can improper valve lash add to the problem? Are parts of the decompression system accessible from inside the valve/cam cover, or is further disassembly required?

The decompressor is fitted to the camshaft pulley, and a light spring holds a curved metal rod into a position that holds open the exhaust valve. When you pull the starter handle, the valve remains open to ease starting effort. Once the camshaft pulley reaches a specific speed, the centrifugal force overcomes the spring and the metal rod moves out of position, allowing the camshaft to fully control the exhaust valve operation (full compression).

Should the spring fail, or if there is wear/damage around the metal rod, it can get 'stuck' in the wrong position, allowing for full compression at all times, regardless of the engine speed. This of course can result in a kick or hard starting effort.

All the parts are accessible under the cylinder head cover. Remove and inspect the rod, spring, and look carefully for debris, damage to the pulley, or wear that could cause the rod to stick in the full compression position.

 

[tomocar]

Hello - can I re-open an older thread like this?

I have a similar problem on a GCV 190 - kicks back so hard the starter handle whips me in the stomach and it hurts!

I couldn't get the flywheel nut off so I thought I'd check the valves and decompression spring thing first, and found that the exhaust valve rocker was actually broken - it was flopping so loose I don't think the exhaust valve could have been opening at all. (And the decompressor looked fine.) Anyway, went to the Honda parts store and bought the new rocker, and asked the guy: what could have caused this? Should I suspect some other problem or could it just be this? He said it's probably just this - replace it and it should be fine. So did that - and dang it, I still get the gut-punching kick back.

So I'm back to usual suspect #1 - the flywheel key... So how do I get that nut off? I've been trying with a rubber-belt-wrap wrench-thing around the flywheel and a socket wrench on the nut, but with all my strength I can't get it to budge. Any suggestions? It's not reverse-threaded is it?

Thanks!
Tom

 

[robert@honda]

So I'm back to usual suspect #1 - the flywheel key... So how do I get that nut off? I've been trying with a rubber-belt-wrap wrench-thing around the flywheel and a socket wrench on the nut, but with all my strength I can't get it to budge. Any suggestions? It's not reverse-threaded is it?

Thanks!
Tom

I'm guessing you don't have access to an impact wrench, as that would surely make for quick removal.

Having a helper hold the strap wrench while you turn the socket?

You can dramatically increase the mechanical advantage with a longer ratchet (a.k.a.'breaker bar'). As the great Greek mathematician Archimedes said, 'Give me a lever and a place to stand and I will move the earth.'

 

[tomocar]

Thanks Robert, but I am embarrassed to say I made a mistake. Indeed the broken rocker arm was the problem - I just messed up the gap setting procedure - I must have been off my rocker! :laughing:

So I don't need to take the flywheel off - motor runs fine now.

BTW: to anyone else reading this thread, so this is another thing that can cause one hell of a kick-back: broken rocker.

 

[DPDISXR4Ti]

I have a similar problem on a GCV 190 - kicks back so hard the starter handle whips me in the stomach and it hurts!

Same story with me - I've got a GCV 190 on my Homelite 3100 PSI pressure washer - the kick-back wants to rip the handle out of my hand even with a death-grip on it. Does everything that Robert posted above regarding the 160 hold the same for the 190?

 

[golfergordy]

I picked up a used HR215 with the same kick-back problem. I found the valves to be out of adjustment, and re-setting the valves to the proper gap solved this problem.