OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions On Honda Engines Honda GCV160 Knocking Noise

Got a Honda GCV160 on Victa Commmando. My 7 year old usually mows the spectic area which is 1-2 times a week depending on what season/rainfall etc. He has ran over a thong and it has started making a pretty bad knocking noise. I took the plate off and notice that the shaft moves up and down a few mm and makes a knocking noise. I have asked around and some people have said that is normal. I have done a small video of it.

I can't see your video since firefox and flashplayer are currently not cooperating with each other. However, up to about 1 or 1.5 mm end float is typical of vertical Hondas I have worked on. So far it has not caused a knock. If it is actually "a few mm", it sounds as if something is wrong. End float becomes a serious problem if it is large enough to cause one side of the connecting rod to touch the side of the big-end journal.

You should inspect the Power Take-Off (engine output shaft) with the blade plate mounting boss removed, and see if you have something wound around the shaft at the lower main bearing. Also see if the center bolt holding the blade boss on the PTO is loose or a spacer is missing, allowing the boss to slide axially on the shaft.

The engine certainly shouldn't knock, but at this point I can't guess what has gone wrong.

Thanks for the fast reply. Sorry about video. Wasn't sure what else to use. Only just signed up to youtube then to actually upload the video. What is the method on removing the blade plate mounting boss? Are you mean't to use a gear puller? And where is the best place to get a new one as I snapped mine today. Can find diagrams on all other parts on the mower/motor but not that part.

Found the boss in the online shop - https://www.outdoorking-forum.com.au/lawn-mo...lts-lawnmower/victa-disc-boss-late-model
Anyone know if it is possible to run it the way H�nda's are with just a large single blade or won't work as crank different and chassis won't allow it?

First, Honda bosses are on a parallel shaft, driven by a key. To remove them you back off the center bolt about three turns and use a gear puller to move the boss a millimetre or so. Then remove the center bolt and substitute any old bolt of small enough diameter to just fit inside the crankshaft thread, about 25 mm longer than the original center bolt. Use that to pull the boss off another 20 mm, then you should be able to pull it off the rest of the way by hand. It is helpful to drill an impression in the center of the head of the old bolt, to locate the draw screw of the puller.

I don't know of a cheap place to buy decent pullers. I'd probably take a look at speed shops and Bunnings.

Genuine Hondas can normally be set up in either of two ways: with a boss, blade plate and swing-out blades, or a different boss, mounting adaptors, and bar blade. The crankshaft extension and chassis will accept either. The blade plate kit is specifically Australian, so you won't find it on imported models, but for 19 or 21" models, the Australian kit will fit straight on. My favourite Honda came with a bar blade but it didn't take long to realise that was an awful idea: lousy cutting, lousy draft into the catcher, unsafe, and a pain in the backside to keep sharpening the bar blade. I collected the bits of the Australian kit from ebay and scrap mowers, and fitted it to my imported mower - IMO, a huge improvement. I give no thanks at all to Honda Australia for their design of mower bases, but their blade kit is vastly better than a bar blade.

I have no idea how Victa will have set up that hybrid machine. They may have used a blade plate of their own, with a different offset from the Honda ones.

Haven't really had time or money to work on the mower till this week. Been using other peoples mower or just my ride-on. I replaced the flywheel key even though it didn't look damaged. There still seems to be a knocking sort of noise. When I had the top cover/fuel tank off I could move the flywheel 1 - 1.5mm up and down. If I was to record a small video of it while running what would be the best one to upload so you can view it?

I still can't see your video but I can hear it now, and the sound is much the same as I've heard from multiple Hondas, but the actual movement is what matters rather than the sound. Honda has set a limit for the clearance, which I have outlined in red:


So, it sounds as if you need to make a more precise test to establish whether yours is within the service limit.

Did two more small videos today once home from work.

1st one is just me moving the shaft left and right (need sound)


2nd one is it running. Also blows out a lot of smoke but seems to settle down after awhile.


It does vibrate to, not really bad like some videos I watched on youtube but you can fell it in the handle.

So when it is over it's service limit was does that mean? Bent crankshaft or more? I measured 1.5mm while lifting the flywheel up and down and getting someone to hold a ruler next to it. Mower is just over 1 year old.

I don't get an image from either of your videos. If the crankshaft endfloat is over 1 mm, it means the engine is defective. The crankpin is only 1.1 mm wider than the connecting rod, so the crankshaft is moving far enough to cause the connecting rod to be pulled too far sideways, which could cause a variety of bad things to happen to the rod and piston. It can't happen due to the crankshaft being bent, though it could happen if the crankshaft has been compressed axially in a press. I'd say it is either wear or defective parts, unless the engine has been damaged in an unusual way.

I can't interpret your comments to understand what you mean regarding vibration. If the engine blows blue exhaust smoke, the engine has a problem and is leaking oil into the combustion chamber. There are several possible causes of this. Black exhaust smoke would probably be a result of running the engine with the choke operating, or when the carburetor had been flooding.