Hayter Harrier 56 Briggs and Stratton Quantum engine choke won't close

[SamMowerman]

Hello, I have an old Hayter Harrier 56 which stopped working a few days ago. I was mowing the lawn, and I think it ran out of petrol, as I couldn't see any in the tank. I filled it with petrol and then when I pulled the starter cord, the engine was very difficult to turn over. There was a very hard part every so many rotations (probably only one of the four strokes), and I couldn't get it to start. I drained out the oil and found that there was probably about 200ml in it, and I believe it needs 500ml. I refilled the oil with brand new Hayter engine oil, but the difficulty turning the engine over remained, and it won't start.

I started to take it apart, so I could see the carburretor, and I noticed that the choke doesn't close when the lever is set to the 'tortoise' position, for full choke. I can see that there is a rod that goes to the metal part on the top, which the choke is attached to, but the rod doesn't move back to close the choke (and I presume there is nothing else supposed to do this, unless there was a spring which has gone missing). I believe this rod is somehow connected to the governor on the engine. Should this rod be moving backwards (to the left on the photo) to pull the choke closed when the choke level is on the 'tortoise' setting? You can see that the cable is as tight as it can be, on the top right of the photo. I think in this photo I had manually adjusted the plate which is pointed at by the arrow in the centre of the photo, to close the choke, so it doesn't represent what actually happens when I try to turn the choke on with the handlebar lever.

Many thanks in advance to anybody who can help me, I appreciate you taking the time to answer all the queries on here.

[Mick]

The engine tight spot is a bit difficult to diagnose without seeing it to be honest. 

The carburettor on your machine doesn't have a choke and uses a primer. So that shaft is referred to a Throttle shaft.  It's quite normal for it to float way from the idle speed screw when the engine is stopped. The governor will push it back when it's running.

[SamMowerman]

Hi Mick, thanks for your reply. I've attached three more photos I took, looking into the carburettor - isn't the flap thingy the choke? So when I put the lever on the tortoise setting, what does it do in the carburettor? (I sort of understand simple engines, but patently not very well!)

[Mick]

Forgot to say, welcome to TGMForum.

The flap you see is called the throttle butterfly, it controls the speed of the engine along with fuel and air mixture.  A choke would be a second butterfly at the other end of the carb which restricts the airflow thus making it suck more fuel for starting.