What's on your bench today?

[sloth]

Should be OK, I would fit new bearings and seals as the busted crank end may have put undue stress on the bearing.

 

If the replacement crank is still in the crankcases then make sure the thing isn't worn where the bearings run on it. The MS200 is unusual where the bearings are roller type and run actually on the crank shaft itself and the one on the clutch side can suffer due to operators overtightening the chain:thumbdown:

 

Ah, good info. Thanks again. When I get round to it, I may do a step by step thread with pics...

[Joe Newton]

Fit either the OEM ones or Caber rings - the Chinese ones can be brittle and snag which isn't good:thumbdown:

 

Aah, I've ordered a new piston from Mr Solutions. I don't know the make, but I couldn't find any other suppliers. Should I cancel?

 

I can't quite see how I would remove the old piston. It looks like a cylindrical pin I'll have to punch out. Care to humour a novice?

 

Also the torx bolt hole in the bottom left of the flywheel cover has snapped, so the bolt hole fell off once I removed the cover. I think its too small to weld, but will something like JB Weld hold it? Its not such a big deal if not.

 

On the bright side, I've learnt more about the anatomy of a saw today than I ever have!

[GardenKit]

I did not get any pics of this, but today I had a Lawnflite brushcutter in that would not start after the owner had 'serviced' it and repaired the air filter cover.

 

He had lost the short 15mm M5 screw which held the air filter cover on, so replaced it with a 40mm self tapping screw, which had 'self tapped' (as they do) straight through the side of the carburettor:biggrin:

 

The air filter was nice and tight though.

[wisecobandit]

Should be OK, I would fit new bearings and seals as the busted crank end may have put undue stress on the bearing.

 

If the replacement crank is still in the crankcases then make sure the thing isn't worn where the bearings run on it. The MS200 is unusual where the bearings are roller type and run actually on the crank shaft itself and the one on the clutch side can suffer due to operators overtightening the chain:thumbdown:

Well never knew they used roller bearings so ive learnt something tonight, is that both sides Spud or just the flywheel side?

Ive got an early 1973 stihl 051 which uses roller bearings but the 1976 051 has ball bearings as they changed after they realised the roller bearings where eating into the crankshaft. Amazed they didn't learn there lesson 30 years ago

[spudulike]

Well never knew they used roller bearings so ive learnt something tonight, is that both sides Spud or just the flywheel side?

Ive got an early 1973 stihl 051 which uses roller bearings but the 1976 051 has ball bearings as they changed after they realised the roller bearings where eating into the crankshaft. Amazed they didn't learn there lesson 30 years ago

 

The bearings are strange looking bearings that look like this - http://thumbs1.ebaystatic.com/d/l225/m/mzRSROUcHRbXp44mbLp_GpQ.jpg

 

I ment needle roller bearing but the needles are more like rollers tham ball races.

 

Got them both sides, exactly the same.

[spudulike]

Aah, I've ordered a new piston from Mr Solutions. I don't know the make, but I couldn't find any other suppliers. Should I cancel?

 

I can't quite see how I would remove the old piston. It looks like a cylindrical pin I'll have to punch out. Care to humour a novice?

 

Also the torx bolt hole in the bottom left of the flywheel cover has snapped, so the bolt hole fell off once I removed the cover. I think its too small to weld, but will something like JB Weld hold it? Its not such a big deal if not.

 

On the bright side, I've learnt more about the anatomy of a saw today than I ever have!

 

The pin is a gudgeon pin or wrist pin if in the US. it is held in place with circlips that can be little mothers to remove - just be damn sure when you fit the new piston that the circlips are in the groove in the piston otherwise the circlip will spring out and mash your cylinder.

 

You will also need to ensure the arrow is pointing toward your exhaust port and make sure the ring ends are in the same position as the original as I have known Chinese pistons to have arrows pointing in the wrong direction.

 

The lug - try and drill and pin it - JB won't hold it, I have pop rivited and pinned parts before but without seeing it......or by a pattern part if you can find one or secondhand unit.

 

As far as pistons go, in order of best first OEM (original equipment), Meteor, Episan, Golf, Chinese. With rings - OEM, Caber, Chinese....I have known Chinese rings to fail and to do severe damage.

[felixthelogchopper]

I have been swearing at a Stihl HS81R hedgetrimmer today. It was struggling to start this morning so I started to have a look at it on the bench. I found the plug wasn't in tight but that wasn't the problem. Trying to check the plug was sparking was a nightmare as you can't see it when you earth it. Eventually, with the workshop lights off, I could see a spark but gauging the quality of it was impossible. Satisfied that it was actually sparking, I turned my attention to trying to get the thing to actually start. I found that it would fire on choke then start after several attempts but I had to keep pumping the bulb to get the petrol through. Once it fired a few times, it would idle then die, and would not fire again unless I pumped more fuel through with the bulb. This made me think it could be the tank vent, especially as I got a hiss when I opened the fuel cap, but even with the vent out it still idles then dies. Squeezing the throttle just makes it die a bit quicker. Any ideas?

[sloth]

Blocked fuel filter, or lines? maybe

[felixthelogchopper]

Blocked fuel filter, or lines? maybe

 

I was thinking that but it doesn't explain the hiss. I've taken the vent apart and blown it all through but still no better.

[Rich2484]

Now I'm going for a bit of a stab at this Felix.

 

The bulb only brings up enough fuel to get the pressure up. After that the engine does the rest.

 

Is the plug getting wet after trying to start?

 

I would look into the diaphragm, in the carb. Or the impulse line,

 

I wouldn't get stuck on the hiss from the tank. It's only from pressure that is a good thing as it pressurises the tank pushing fuel up to carb.