What's on your bench today?

[GardenKit]

Not on my bench but in the dealers. Our FS450 this morning had a massive amount of fuel in the exhaust (well over half way full). We got it running but wasn't happy. It wont idle and it keeps popping through the carb. It is the 6th time in the past 2 months we have had to pour fuel out of the exhaust. We store it engine upright hanging off a bracket with a clamp on the shaft. Other than the way we store it any ideas what is causing the fuel to collect in the exhaust?

Matt, I think its got to be a carb problem, either due to dirt or wear of the metering valve, or due to a defect in the carb body. Your dealer should be able to test the carb for leaks by pressurising it under water.

The solution may well be a new carb.

[spudulike]

Not on my bench but in the dealers. Our FS450 this morning had a massive amount of fuel in the exhaust (well over half way full). We got it running but wasn't happy. It wont idle and it keeps popping through the carb. It is the 6th time in the past 2 months we have had to pour fuel out of the exhaust. We store it engine upright hanging off a bracket with a clamp on the shaft. Other than the way we store it any ideas what is causing the fuel to collect in the exhaust?

 

Usual reasons for excessive fuel to be in the exhaust are a blocked exhaust (blocked baffle or spark arrestor) or a leaking needle valve in the carb allowing fuel to leak through. Only other reason could be an excessively rich mix on the carb settings.

 

If it turns out to be something like pressure building up in the fuel tank through temperature changes, you may be able to fit some sort of shut off valve in the fuel line.

[spudulike]

Just to prove what can be done with a bad seize on a chainsaw, this one I believe was old fuel but ALWAYS pressure and vac test the saw on re-assembly.

 

First picture shows some heavy transfer of the piston aluminium on to the cylinder bore - got to say this looked borderline to me but I always try to save the original OEM part than fit a poorer quality Chinese part.

 

Applied the magic chemicals and bingo - it cleaned up pretty well, slight score to the right of the exhaust port and a slight score from the exhaust port to the top of the bore but IMO, still better to fit a decent quality piston and this saw will make compression and run well after a few tanks through it.

 

Shows clearly what can be done though:thumbup:

[Adamam]

254xp. My new project saw.

 

Super-low compression. Posted to me full of fuel! There are some real geniuses about.

 

Given super-low compression, is there any hope of salvaging the cylinder? The listing (in retrospect) intentionally skated round piston/cylinder problems. If I'd known the piston was done, I wouldn't have bought given the price of replacement cylinders...

 

I haven't stripped the saw down yet; it doesn't seem worth the effort if it's guaranteed that the cylinder needs replacing since I'm not planning on spazzing £100 on a replacement.

 

Spud?

 

(pweeeeeze!)

[Rich2484]

I had one a while ago, stripped it and the barrel was fine, the ring had gone. 15 quid and away it went.

[spudulike]

254xp. My new project saw.

 

Super-low compression. Posted to me full of fuel! There are some real geniuses about.

 

Given super-low compression, is there any hope of salvaging the cylinder? The listing (in retrospect) intentionally skated round piston/cylinder problems. If I'd known the piston was done, I wouldn't have bought given the price of replacement cylinders...

 

I haven't stripped the saw down yet; it doesn't seem worth the effort if it's guaranteed that the cylinder needs replacing since I'm not planning on spazzing £100 on a replacement.

 

Spud?

 

(pweeeeeze!)

 

I have got to say that I have around a 90% success rate salvaging cylinders, I have probably done 40-50 by now and always try to fit a quality piston to ensure a snug fit, Meteor wherever possible as they are without doubt the best after OEM ones and at £25 worth every penny IMO.

 

The 254 is a good saw and worth around £200 in GWO. Not sure I managed to get Meteor for the one I did on the first page of this thread but fitted a Golf one and used OEM circlips as the ones supplied are never great.

 

As long as the plating is intact and there are no gouges out of the transfers or deep scores above the exhaust port then it will work.

 

You can see in my images that there was a thick smear of aluminium transfer on the right side of the exhaust port. It took an hour with the area covered in acid to get rid of it but am happy with the end results. A going over with some wet and dry paper, course then fine gets the residue of smeg off.

 

Worse one was the MS880, also within this thread - had a lump of aluminium around 0.3mm thick on the bore that also cleaned up.

 

The art is in clearing ALL the transfer off and leaving the bore very smooth otherwise the ring will be trashed first time out.

 

The cylinder should last for years after this work but if you do this type of work - wear safety glasses and hand protection.

[GardenKit]

Not quite on the bench yet, but in the queue to get there. This lot came in for service yesterday, never had so many in one day. I only just managed to get them inside at night. They need to be back next week so i guess its another weekend working,

[MikeTM150]

good luck with that lot!!! How many weekends on the trot now?

[GardenKit]

good luck with that lot!!! How many weekends on the trot now?

All weekends up to easter, but only one since..... till now!

It has usually eased up by now, but this is a strange year.

[MikeTM150]

ah the joys of running your own business! Well I hope you get them done and finished in time!