Stiga mower won’t run

[AHPP]

28 minutes ago, Muddy42 said:

Yes that's my understanding, the rods and rockers are designed to be the weak point.

 

Yes, there is quite a lot of space around the rods. Maybe to allow oil to move around?

Oil only needs ten thou or something but I assume larger channels are easier to cast or drill too. 

[MattyF]

35 minutes ago, Mick Jones said:

Matty, did you move the rocker arm over to one side to get the bent pushrod out or was the rocker arm like that when you took the valve cover off?

 

Yes mick , it was like that when I took it off.

have straightened the rod and tried to cycle the engine by hand it’s moving that valve but it’s kind of not right it’s moving again up again on the cycle when it should of finished , is that because the rods not perfect 

[Muddy42]

1 hour ago, MattyF said:

Yes mick , it was like that when I took it off.

have straightened the rod and tried to cycle the engine by hand it’s moving that valve but it’s kind of not right it’s moving again up again on the cycle when it should of finished , is that because the rods not perfect 

 

Its hard to say, also the lifter could be bent.  Can you shine a torch in there, not that you can see the lifter from that side.  and onto the pistons?  Can you move the intake valve (bottom one) by hand. You could try swapping the working exhaust rocker and rod onto the intake valve to confirm the moment.

Edited 18 hours ago by Muddy42

[MattyF]

Put it back together after straightening the rod as best as possible , it sounds like it’s missing and won’t rev out.. lots of black smoke .. don’t know if it’s best to assume the crank is bent looking at the push rod in the original photo or try a new rod but I would not of thought it would of made that much difference. 

[Muddy42]

40 minutes ago, MattyF said:

Put it back together after straightening the rod as best as possible , it sounds like it’s missing and won’t rev out.. lots of black smoke .. don’t know if it’s best to assume the crank is bent looking at the push rod in the original photo or try a new rod but I would not of thought it would of made that much difference. 

 

Did you replace the intake rocker arm, which looked broken in your photo?

[MattyF]

17 minutes ago, Muddy42 said:

 

Did you replace the intake rocker arm, which looked broken in your photo?

Rocker arm had just come disconnect.. it didn’t look out of shape next to the other one still in place. 

[AHPP]

Did you check the gaps? Set engine to top dead centre and put feeler gauges under the adjustable threaded bits to set gaps as per engine manual. 

[MattyF]

1 hour ago, AHPP said:

Did you check the gaps? Set engine to top dead centre and put feeler gauges under the adjustable threaded bits to set gaps as per engine manual. 

As best as possible .. I will get a feeler gauge next time I’m in town. Just used an old logging tape cut twice and doubled up as a gauge… I didn’t think it would be that out though.  

[Mick Jones]

7 hours ago, MattyF said:

Yes mick , it was like that when I took it off.

have straightened the rod and tried to cycle the engine by hand it’s moving that valve but it’s kind of not right it’s moving again up again on the cycle when it should of finished , is that because the rods not perfect 

O.k. so it looks like the pushrods jumped out of its socket on the rocker arm. That would account for the noise you heard. The push rod will certainly need replacing. Set the valve clearances, turn the engine over by hand for a few revolutions then re check the clearances. Then try and run it.

So difficult to tell from photos but hopefully the bottom end should have suffered no damage.

Have a good check of the rocker arm, make sure it's not bent or fractured before you rebuild it.

Good luck and let us know how you get on.

[AHPP]

5 hours ago, MattyF said:

As best as possible .. I will get a feeler gauge next time I’m in town. Just used an old logging tape cut twice and doubled up as a gauge… I didn’t think it would be that out though.  

 

If caught without feelers again, you could use other stuff under the other side (or even a comparable engine) and replicate that amount of drag on the bad side. Your fingers can feel remarkably small differences. Anyone who's jogged a CNC mill down in ten micron and then single micron increments to scratch a gauge under an endmill knows what I mean. You'll even feel the different cutting edges dragging differently. 25 microns is one thou(sandth of an inch).