What's on your bench today?

[Muddy42]

On 20/12/2023 at 19:01, spudulike said:

Lets hope so. One thing to check, if you haven't already, is the state of the piston through the exhaust port, make sure the exhaust port isn't coked up and check the exhaust isn't blocked. All may give rise to poor running.

 

 

update after a few weeks....I got to the stage where I felt I had tried everything within my capability.  So I took the strimmer to a fellow who know his two strokes (probably takes milk in his tea in a 50:1). He tested the spark and diagnosed an issue with the ignition unit - it sparks but the strength or timing of the spark was out. Anyway now it runs after we pinched an ignition unit from a donor engine. Thanks for the help everyone.

 

[spudulike]

Excellent, I have had coils give a few sparks when first pulled and then nothing. Glad it is sorted and another machine lives rather than being deposited in landfill.

[pleasant]

Strange one today, so any advice and suggestions would be welcome.

 

We have taken in an Echo CS420ES saw. We aren't familiar with them as we are other brands, but a good customer who also has brands we are main agents for, so didn't want to upset him by not at least offering to take a look.

 

Guy said on idle the chain was still spinning.

 

Removed the chain cover and bar and chain and could see the chain had 'slid' off the sprocket teeth on the drum and was effectively on direct drive hence the spinning. This during recent use has caused the chain drive links to grind out a groove in the alloy oil pump body as well as wearing down the nylon oil pump drive gear teeth.

 

Removed the clutch and drum and really couldn't find anything wrong per se. However despite replacing the clutch and tightening it right back up again there is around 4-5mm of 'end float' between the teeth on the sprocket and the teeth on the oil pump gear in the body of the saw. You can pull the drum in and out-thus, away from the nylon oil pump gear teeth- this is why the chain has come off and got jammed and would be why the oil pump isn't working as the gears aren't meshing. I will attach some pics of the air gap between the two. No washers are missing and the teeth on the sprocket don't look worn down in terms of width, although not knowing these saws too well I am not sure how wide the sprocket teeth should be...they do look quite short compared to the ones I usually deal with but the face of the teeth between the drum and the body don't look ground down shorter than factory? Ideally i need a sprocket with wider drive teeth to take up the play between the drum and the body, but never had to address that before- ever.

Edited January 23 by pleasant

[gand]

2 hours ago, pleasant said:

Strange one today, so any advice and suggestions would be welcome.

 

We have taken in an Echo CS420ES saw. We aren't familiar with them as we are other brands, but a good customer who also has brands we are main agents for, so didn't want to upset him by not at least offering to take a look.

 

Guy said on idle the chain was still spinning.

 

Removed the chain cover and bar and chain and could see the chain had 'slid' off the sprocket teeth on the drum and was effectively on direct drive hence the spinning. This during recent use has caused the chain drive links to grind out a groove in the alloy oil pump body as well as wearing down the nylon oil pump drive gear teeth.

 

Removed the clutch and drum and really couldn't find anything wrong per se. However despite replacing the clutch and tightening it right back up again there is around 4-5mm of 'end float' between the teeth on the sprocket and the teeth on the oil pump gear in the body of the saw. You can pull the drum in and out-thus, away from the nylon oil pump gear teeth- this is why the chain has come off and got jammed and would be why the oil pump isn't working as the gears aren't meshing. I will attach some pics of the air gap between the two. No washers are missing and the teeth on the sprocket don't look worn down in terms of width, although not knowing these saws too well I am not sure how wide the sprocket teeth should be...they do look quite short compared to the ones I usually deal with but the face of the teeth between the drum and the body don't look ground down shorter than factory? Ideally i need a sprocket with wider drive teeth to take up the play between the drum and the body, but never had to address that before- ever.

I've sent you a pm 👍

[peatff]

I'd start with a new sprocket/clutch drum and oil pump drive. They should have sharper edges and mesh together but those ones are well chewed.

[pleasant]

12 hours ago, gand said:

I've sent you a pm 👍

Replied.....thanks.

 

Things have moved on since last night after I text the customer. See my comment below.

[pleasant]

Right. I sent the photos to customer last night explaining we know what is wrong, but cannot work out why. I asked if he has had some work done on it recently elsewhere?

 

Customer rings me this morning to inform me he took it somewhere else last year and had a new drum fitted by them and has had issues with it since then!

 

Would seem the previous repairer may well have fitted an incorrect drum.

 

I am now going to order a correct genuine drum and compare.

 

Keep you posted. 

 

 

 

 

[spudulike]

A good result...I think....... logic takes over with things like this and stupidity of others can often be the route cause. 

Hope it works out.

[bmp01]

6 hours ago, pleasant said:

Right. I sent the photos to customer last night explaining we know what is wrong, but cannot work out why. I asked if he has had some work done on it recently elsewhere?

 

Customer rings me this morning to inform me he took it somewhere else last year and had a new drum fitted by them and has had issues with it since then!

 

Would seem the previous repairer may well have fitted an incorrect drum.

 

I am now going to order a correct genuine drum and compare.

 

Keep you posted. 

 

 

 

 

The fact it wasnt running right since the last bad repair hasnt stopped the guy from using it - judging by the chain imprint (wear) in the spur gear teeth. No sense of mechnical sympathy = bigger repair bill.

[gand]

9 hours ago, pleasant said:

Replied.....thanks.

 

Things have moved on since last night after I text the customer. See my comment below.

👍 got your reply, but been flat out today. Still working now! Trying to figure out what Stihl chains I'll need for the next 2 months and what climbing gear will be needed in the next month. Oh the joys!