OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Engines Questions on Other Engines Valve Clearance on 138cc YardKing

Mowers are scarce lately at my recycle centre so I decided to give this YardKing a go. How low can I sink to. Anyway, I have it running but there are a couple of problems. There is a surging/hunting at the "Start" throttle position but it goes away after about 20 seconds so I'm not too concerned with that (carby has been cleaned twice). What the main problem is, is a little bit of hand wrenching on pull starting. Since it's only a small engine I can pull through it but I'd like to fix it.
Since the mower runs fine after the surging stops I am thinking this is a valve clearance problem. However, I can't find what the clearances should be anywhere on the net. When I took off the valve cover I could see the adjusting nuts but there weren't any lock nuts behind them.
So, does anyone know what the clearance should be and secondly, should there be locking nuts?

Edit: The clearance was way too much so I just did them up randomly and it's easier to start now. The surging has gone too. But I feel the clearances will wander without locking nuts.

G'day sparker



The rocker post nuts usually have a grub screw in the centre of the adjustment nut that locks the nut
to the rocker post.

A little difficult to see in your image but the centre looks star shaped or Allen key.

Cheers
Max.

If I were being particularly uncharitable to Yardkings I would suggest the best valve clearance is 50m off a cliff

But anyway Max is spot on that the outer nut acts as the locking nut - though I agree with you they obviously don't hold that well as they seem to need adjusting every few years as opposed to some genuine Hondas I have seen that go 15+ years between them (double nuts give better locking)

Also popped into the local tip today - 30 stuffed half crank line trimmers, a 16in Sprinter, 18in 909 GMC mower, 2 more chondas - thats it.

Though I did grab a early Victa poly catcher with the top mountings (early mayfair low arch models) and it still had the magic eye indicator

I would do Intake 0.15mm, exhaust 0.20mm (generic Honda spec). The hard (and odd) bit is some seem to tighten with use (losing compression) whilst others loosen.

That sounds like the catcher from the late 60's and early 70s Cortina and Corvette premium mid arch chassis, also used for store brands until the store brand thumb latch high arches came out in the 1977 season. It has the little shafts sticking out that go into the handlebar hooks like the first VC high arch bases.

Terrible garbage those things I won't look at them anymore

That the one MF - this one has the little shafts that stick out above the catcher opening like this

https://www.outdoorking-forum.com.au/forum/ubbthreads.php/topics/69702/victa-corvette.html

I just realised something Tyles, the VC series which has the same handle hook method for the catcher took over as the premium mower line from the mid arch chassis, which had been the highest arch up to that point.
Cars aren't the only thing that has significant moments.

Thanks for the information. This YardKing is a self propelled 16" cut mower. It's a toy mower basically. and normally I wouldn't be interested in them but it shows how desperate I am. I'll have a closer look at the top of the threads to see if there's a grub screw/allen key fitting.