Trying to research a metal knocking noise experienced when I engage the blade clutch. The mower idles fine and runs fine once the blades are spinning but the transition from idle to full operation generates an awful noise. Bearing initially looks good but having it apart tonight for closer inspection. Cant find anything similar in web? Any ideas? Video to follow
Honda 476 Blade Clutch Noise
- Thread starter Pablo131
- Start date
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You’ll see the clutch is held within two prongs and slots.....any excessive wear on these?
A new clutch is around the £200 mark - I’m not sure if internal bits are available though, but I have built up plates with weld before.
John
A new clutch is around the £200 mark - I’m not sure if internal bits are available though, but I have built up plates with weld before.
John
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Started to pull the rotor clutch off expecting to find something obvious but to my untrained eye things look pretty standard. bearing feels reasonable and no parts fell out. I feel sure this is clutch related as the metal knocking sound only occurs when the rotor is in the process of being engaged - not at idle or fully engaged. Anything here not look right??
That looks pretty typically Honda perfect to me......I have replaced a few bearings though - the one with the blue seal.
Top pic......is that plate tight on the crankshaft?
Do check the idlers for wear though, much more common!
Thanks for the pics
John
Top pic......is that plate tight on the crankshaft?
Do check the idlers for wear though, much more common!
Thanks for the pics
John
All you have to do is follow the belt to the belt pulley(s).......any tensioner or guides will be there.
If there aren’t any, reach under the deck and grab the blade (s)......give them a good heave, feeling for play.
Next, do the same with the top pulley....it may have worked loose on the shaft there.
John
If there aren’t any, reach under the deck and grab the blade (s)......give them a good heave, feeling for play.
Next, do the same with the top pulley....it may have worked loose on the shaft there.
John
On this model the belt is tensioned by a spring pulling on a plastic rear roller drive transmission so I am not sure this would generate the metallic knocking - I am sure its centred on the braked rotor clutch so I will try pulling the blades around as you suggest and take a closer look at the pulley. Fingers crossed I can get the Carb sorted tonight so I can get it running
I thought I would drop an update for anyone remotely interested. Having stripped down the clutch and anything remotely connected all was re assembled and the bloody thing wouldnt start. Strip down the carb, clean (twice - hunting first time), new gaskets, fuel etc etc and we have a mower starts first time (ish) and the rotor clutch and drive engage all without a problem. Lawn mowed and all is right with the world......until yesterday.
Filled up with fuel, didn't want to start. Guessed I may have picked up wrong fuel can and used stale fuel. Emptied tank and carb, and tried different fuel. Mower started but the noise was back. See link
I intend to drain the fuel again in the next couple of days and try pump fresh fuel and see what happens. If it solves the problem it seems like an unusual scenario ...unless you guys have experienced something similar??
Filled up with fuel, didn't want to start. Guessed I may have picked up wrong fuel can and used stale fuel. Emptied tank and carb, and tried different fuel. Mower started but the noise was back. See link
I intend to drain the fuel again in the next couple of days and try pump fresh fuel and see what happens. If it solves the problem it seems like an unusual scenario ...unless you guys have experienced something similar??
Many thanks indeed for the splendid video!
As you engage the blade drive - with the yellow button - the motor slows a little, blows a little blue smoke, and then recovers.....all pretty normal but the smoke indicates some cylinder wear (unless the oil level is very high).
The motor doesn't recover too well towards the end of the video, and the fact that it is almost about to stall could indicate some fuel starvation.
This is also endorsed by the engine seeming to lose power....it will do as with the blade engaged the engine needs more fuel.
When you cleaned the carb, did you remove the main jet, followed by the emulsion tube above it?
Do keep the oil level correct as per the dipstick, and see the paper air cleaner is free of oil and grass, etc.
The plug is an NGK BPR6ES - worth changing from time to time.
John
As you engage the blade drive - with the yellow button - the motor slows a little, blows a little blue smoke, and then recovers.....all pretty normal but the smoke indicates some cylinder wear (unless the oil level is very high).
The motor doesn't recover too well towards the end of the video, and the fact that it is almost about to stall could indicate some fuel starvation.
This is also endorsed by the engine seeming to lose power....it will do as with the blade engaged the engine needs more fuel.
When you cleaned the carb, did you remove the main jet, followed by the emulsion tube above it?
Do keep the oil level correct as per the dipstick, and see the paper air cleaner is free of oil and grass, etc.
The plug is an NGK BPR6ES - worth changing from time to time.
John
Hi John - thanks for your comments. I do think there maybe some cylinder wear as its a few years old but I am not overly concerned - generally it runs really well and I dont lose oil. Carb was completely stripped emulsion tubes etc etc twice except for the small captive quarter turn screw (I couldn't get that off and dont know what its for). I will check the oil but filter is new and plug got changed mid season last year.
I still think poor fuel could be the problem - if the octane is down I guess its going to fail under load and maybe the cause of the smoke under load. You are right to say the mower almost stalled - sometimes it does - depends how quickly you load the clutch up - super slow you can get the expected response, slow you see from the video and anything like a normal / quick action it dies or stalls.
I will revert in a few days once I have found time to put fresh fuel in.
I have searched around the web for info but nothing relating to poor fuel problems - odd given how awful our fuel is now. On my small two stoke machines I have given up cleaning carbs due to poor fuel / blockages - you just have to buy a new one. I had hoped 4 strokes would be okay.
I still think poor fuel could be the problem - if the octane is down I guess its going to fail under load and maybe the cause of the smoke under load. You are right to say the mower almost stalled - sometimes it does - depends how quickly you load the clutch up - super slow you can get the expected response, slow you see from the video and anything like a normal / quick action it dies or stalls.
I will revert in a few days once I have found time to put fresh fuel in.
I have searched around the web for info but nothing relating to poor fuel problems - odd given how awful our fuel is now. On my small two stoke machines I have given up cleaning carbs due to poor fuel / blockages - you just have to buy a new one. I had hoped 4 strokes would be okay.
Attachments
That quarter turn screw is actually the pilot mixture adjustment.....Honda have made the adjustment minimal to minimise pollution!
If you have to remove the screw, the lead lug is cut off and the screw can be fully undone.....there's a plain brass head underneath the cap.
The pilot jet is actually hidden by that screw, under the Phillips screw that's just visible slightly to the left.
This one gets its air bleed from one of the small holes drilled to the side of the main choke - looking at the carb with the air cleaner box removed.
All the carburettor tiny orifices need to be flushed through with carb cleaner and preferably compressed air to guarantee full performance.
John
If you have to remove the screw, the lead lug is cut off and the screw can be fully undone.....there's a plain brass head underneath the cap.
The pilot jet is actually hidden by that screw, under the Phillips screw that's just visible slightly to the left.
This one gets its air bleed from one of the small holes drilled to the side of the main choke - looking at the carb with the air cleaner box removed.
All the carburettor tiny orifices need to be flushed through with carb cleaner and preferably compressed air to guarantee full performance.
John
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