What's on your bench today?

[spudulike]

Well Christmas is coming so if the family have twisted your melon and the TV is shocking then having a bit of a fiddle with this bit of kit sounds like a happy retreat to me!! 

This PDF may help you: -

https://www.motoruf.de/mo/ersatzteillisten/FTP/McCulloch/Ersatzteillisten/IPL, McCulloch, PM2000, PM2100, PM2500, PM2600, GT40-42, GT50-52, Prefix 03, 1997-09, Brush Cutter.pdf

 

[Muddy42]

 

On 14/12/2023 at 09:18, Muddy42 said:

 

Thanks Spud.  Yes the diaphragms are gone, but I am confident everything else in the carb is OK.

 

Its a cable type and I can turn the head from the engine end by turning the cable.  Yes there is something seized in the clutch and I havn't been able to get the head apart (as if to add more string). I will keep working on these last two aspects before I spend money on the carb kit and correct lines.

 

@spudulike  @pleasant

I got the re-greased the shaft (correction its a solid shaft) and freed up the clutch. I'm not sure where the issue was exactly but the mechanism feels better now.   I've replaced the larger carb diaphrams - fuel pump and metering sides.  It runs for longer now but still dies after a few seconds. I suspect a deeper issue with the carb or a leak in the purge bulb.  Any other ideas?

[spudulike]

The BIG question is...have you swapped out the fuel lines and fuel filter? The McCulloch alloy fuel filter caught me out once...it looked near new but was stuffed full of alloy oxide corrosion once I got it apart.

Other than that, remove the H&L screws and get some cleaner sprayed down the holes. Try undoing the H&L screws 1/2 and then 1 turn to see if it kicks the machine in to life. Manufacturers often tune their machines on the side of lean to meet emissions and after a while, they run a bit lean.

As always...make sure that the gauze strainer is new or clean. Remove it to check the thing as I once had one that had a scum in the open areas but it looked clean until I took it out.

Lastly - don't discount the plug...if Chinese, junk it and replace with a known good one to see if it is faulty.

[Muddy42]

14 hours ago, spudulike said:

The BIG question is...have you swapped out the fuel lines and fuel filter? The McCulloch alloy fuel filter caught me out once...it looked near new but was stuffed full of alloy oxide corrosion once I got it apart.

Yes, the lines were cracked and the filter was dirty.

14 hours ago, spudulike said:

Other than that, remove the H&L screws and get some cleaner sprayed down the holes. Try undoing the H&L screws 1/2 and then 1 turn to see if it kicks the machine in to life. Manufacturers often tune their machines on the side of lean to meet emissions and after a while, they run a bit lean.

Yes I've cleaned in there.

14 hours ago, spudulike said:

As always...make sure that the gauze strainer is new or clean. Remove it to check the thing as I once had one that had a scum in the open areas but it looked clean until I took it out.

yes i've cleaned the gauze and underneath it.

14 hours ago, spudulike said:

Lastly - don't discount the plug...if Chinese, junk it and replace with a known good one to see if it is faulty.

yes new plug in.

 

I've just sorted a leak in the purge bulb and the carb now holds pressure when applied to the fuel intake.

 

The machine seems to fire a bit better with the L jet out too far (2 turns even) or choke open.  Both sides of the carb seem wet, so I think there is still an air leak somewhere.  The gasket between the carb and the cylinder is pretty worn and ripped and might be sucking air, so I'm going to try making a new one next.

 

Thanks!

Edited December 19, 2023 by Muddy42

[spudulike]

Are you still pissing about with those hardened diaphragms? If so, it is no wonder the engine isn't liking it. The diaphragms need to flex in and out so they can keep a good charge of fuel in the diaphragm chamber and operate the needle valve when necessary.

My old Zenoah strimmer was similar and now it has given me around 10 years excellent service.

Just get on Ebay and get the cheapest kit as it will be better than the one you are probably trying to use......unless you have changed it.

Is the needle arm at the right height?

 

[adw]

And some fell on stoney ground!

[Muddy42]

50 minutes ago, spudulike said:

Are you still pissing about with those hardened diaphragms? If so, it is no wonder the engine isn't liking it. The diaphragms need to flex in and out so they can keep a good charge of fuel in the diaphragm chamber and operate the needle valve when necessary.

My old Zenoah strimmer was similar and now it has given me around 10 years excellent service.

Just get on Ebay and get the cheapest kit as it will be better than the one you are probably trying to use......unless you have changed it.

Is the needle arm at the right height?

 

sorry, I should have said Ive installed new diaphrams from a cheap kit. Needle arm is currently just below the surrounding metal (but only by visual reference to a straight edge, as I dont have a guage).

 

I’ve cleaned deeper into the carb today and made a new gasket for between the carb and cylinder. Lets see, I’ll try and start it again tomorrow.

 

thanks again.

[spudulike]

OK, that is good..all the gaskets in the correct order I hope? I don't know your skill set so worth asking as if the spacer gasket is in the incorrect place on the pump gasket or metering diaphragm, it will cock up the running.

Try lifting the metering arm a little if you don't get any joy....worth a punt but if it floods, you have gone too far.

[Muddy42]

1 hour ago, spudulike said:

OK, that is good..all the gaskets in the correct order I hope? I don't know your skill set so worth asking as if the spacer gasket is in the incorrect place on the pump gasket or metering diaphragm, it will cock up the running.

Try lifting the metering arm a little if you don't get any joy....worth a punt but if it floods, you have gone too far.

Yes the gaskets are on the right way. I have just re-checked, as my skill level is ‘always learning.’ Hopefully the carb cleaning and new cylinder/carb gasket will make a difference.

Edited December 19, 2023 by Muddy42

[spudulike]

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.