372xp won’t start

[openspaceman]

1 hour ago, BigRon said:

Photos on thread now sir

Stubby has said much what I would except it has lightly seized from looking at the marks on the piston and rings with the skirt being clear. Ideally a replacement meteor piston and as Stubby says do not fit gudgeon pin circlips with tangs, reuse originals.

Edited Wednesday at 17:49 by openspaceman

[spudulike]

Yup, a bit of a mess. One thing to add to my original thinking that seizure may have been caused by the impulse coming off is that the fuel lines on older 372s can wear through and leak air in to the fuel line causing running issues.

What I am saying is.....make sure the fuel system is checked over and a vac/pressure check is done after repairing the damage and tach tune the rebuilt saw to ensure good running.

Fortunately the 372 cylinder is pretty robust so can often be salvaged.

[Fatboy2017]

In the first picture it looks like there is a quite a build up of carbon? Could be carbon damage? What oil and ratio do you run?

[spudulike]

I have never seen damage caused by carbon. I have seen partially blocked exhaust ports, even had a saw not making it over TDC caused by a lump of carbon on the squish band but not seen damage that would cause this sort of issue.

My thinking is it will either be a big air leak caused by component failure or a mix of slight air leak, saw a bit lean, possibly dirt or leak in some part of the fuel system. 

This is my experience with these sort of issues.

[BigRon]

23 hours ago, Fatboy2017 said:

In the first picture it looks like there is a quite a build up of carbon? Could be carbon damage? What oil and ratio do you run?

40:1 for this saw and husqvarna xp oil. Pretty anal about my fuel and mixes, no fuel sits and if it’s not used it goes.

[Mick Dempsey]

5 minutes ago, BigRon said:

40:1 for this saw and husqvarna xp oil. Pretty anal about my fuel and mixes, no fuel sits and if it’s not used it goes.

Should be 50:1

Edited 13 hours ago by Mick Dempsey

[BigRon]

4 minutes ago, Mick Dempsey said:

Should be 50:1

Don’t think that’s going to lean it out though is it?

[Mick Dempsey]

1 minute ago, BigRon said:

Don’t think that’s going to lean it out though is it?

The manufacturers recommend 50:1 for a reason.

[BigRon]

Just now, Mick Dempsey said:

The manufacturers recommend 50:1 for a reason.

I would agree, I just don’t think 40:1 or slightly richer than 50:1 with good fuel and oil is going to have caused this.

[Mick Dempsey]

Just now, BigRon said:

I would agree, I just don’t think 40:1 or slightly richer than 50:1 with good fuel and oil is going to have caused this.

I can’t argue with you about that tbh.

How old is the saw?