spudulike

Nice one

If that saw was with me, the carb would go in the cleaner for a deep clean and a new carb kit would be fitted, if that didn't do it then the accelerator pump (yup, it does have one) would be replaced or disabled. If that doesn't do it, I would try to find a secondhand one on ebay etc. other than that - new carb time - that is assuming that the saw is holding pressure/vacuum and that the fuel lines, breathers and comression are all good! If the L screw is doing nothing and the throttle valve is correcctly set at a tad off fully closed, the fuel has to be coming from somewhere to create an idle - the only places left are the accelerator pump and high speed check valve IMO!

The problem will be that when the new aftermarket carb is fitted, if the symptom is still there, is it something else or an issue with the part:confused1: I did a 372XP recently and the carb settings which should be 1 & 1 ended up being 1/2 and 1 1/2 - a less experienced guy would have not been able to tune it in. Saying that, the saw did run OK and was sporting an aftermarket coil as well!

Get your carb kits from Rowena motors, the UK agent for all the main carb manufacturers, crap website but very helpful and you usally receive your order in 24 hrs, just mail them with your carb type and ask for a paypal request.

Always a pleasure and glad it is going well:thumbup:

It was IPOSTPARCELS whom I usually rate but this Irish delivery was a mare and not impressed by their customer services, shame they don't match up to mine!

The Parcel LOST IN SPACE.......actually Ireland has landed and I have been informed the ported 357XP "Is a bloody beast" so I am happy at long last. Two weeks of stress - bloody couriers!

One thought - put that pumping diaphragm against a light and use a magnifying glass to check for small holes - had this befre and an cause issues!

With the carb off and looking down the bore of the carb against a light source, how much gap is around the throttle plate and if you undo the idle screw, does it close completely? You may have a severely worn L screw or seat that is letting fuel through when it shouldn't - in normal operation, the screw should cut the fuel off when wound in!

That Jose fella is making the point I was getting to in non technical terms as above. If the idle speed is too high, the L screw will do bugger all as the H speed check valve will be in action - so..........set the carb on one turn and one turn, start the machine and see what the idle does, if it is in act too high, lower the idle speed using the LA (idle) screw. Once the idle is around 2700 rpm, you should be able to adjust the L screw correctly. Try it - the Chinese carbs may be worth a go but don't expect too much!

You will not see a leaking welch plug, do yourself a favour, take the carb off, if you have solvent in a can, carb cleaner, brake ceaner non oil based, take the L screw out, blast a little in there and also on top of the plug. Leave to dry, get some superglue and work a little around the welch plug with a thin blunt instrument - tweezer ends, blunt small screw driver etc. Clean off the excess and leave to dry for a few hours or better still, overnight. really push down around the plug - dont go through it but don't ponce around:lol: Try it again and the L screw, fully screwed in should kill the idle - as I said, the saw I had in recently did what yours is doing and I tracedit back to a leaking welch plug - it was a 365 with a Zama carb - the oval plugs tend to leak! You could try another carb if you know of someone with one of these saws.

It is probably just exhaust smoke, just make sure the valve opens and closes cleanly by pulling and pushing it and make sure the shaft isn't bent by spinning the top round and make sure the top doesn't wobble from side to side. If you REALLY doubt it, change it as if it snaps, the head will end up in the combustion chamber:thumbdown:

Bill - you are special to all of us on Arbtalk:lol:

The limiters are the coloured plastic caps and Not the springs. The factory settings are used to start, you then adjist the idle and L screw and then tach to achieve the correct max revs! The plug colour -after 15-30 mins, the plug will colour up and should achieve a nice coffee brown colour - it is best to do some long cuts before you stop the machine - you will get by without pulling the plug after stopping the saw mid cut - still remember holding the old 400/4 flat out before killing the engine and pulling in the clutch - around 100mph I think - on private land of course:001_rolleyes:

Most carbs tune up in a very similar way and if the L screw is making no difference then I suspect a fault. The theory is that if the screw is turned all the way in, the engine will die as it is getting no fuel. If it continues to run, I would suspect a leaking welch plug allowing fuel to be picked up through the leak rather than via the normal route - past the L screw. One thing I have found on some saws that have been messes around with - the idle screw is turned well in and the L screw is well out of position so would personally take the limiters off and turn the screws all the way in then both out one turn and then lower the idle until the idle is around right and then re adjust the L screw to make sure it is OK. I usually use a tach to adjust the carb and that is on a saw that has been checked over - fuel system OK, the throttle is being held open to its maximum opening, breathers etc You can check the plug colour and it gives an excellent indication things are correct but the tach does do this in a much shorter time - I can't cut a cubic ton and then do a plug chop on each saw - the tach as well as the factory settings give a nice clean easy way to set a saw up and will be used by any decent tech. If the tach is used correctly, the plug colour should be OK. The method you have adopted is fine! Custom tuned saws are a different beast and to go by the sound/plug colour is common but would still use a tach to bench mark a saw - I usually set a tuned saw up to maximum revs or a few Krpm over if it is heavily fourstroking still.

It looks like that MS201 cover has seen some heat from the brake band rubbing on the clutch drum, I reckin it has disorted the moulding that holds the band making it ride out with use. Looks like new cover time!

The way the rubber and plastic parts work are the rubber manifold pushes over the cylinder inlet connection, the impulse connector is part of this and pushes in to the impulse hole. The plastic part then pushes on to the rubber part to provide a support and retaining function - the clamp around the outer part seals the edges whilst the plastic part gets a retaining pushing effect from its location in to a cut out on the upper crankcase cut out. The issues I have had have been around the impulse and around the outer clamp and will only be noticed by pressure and vacuum testing - predominantly with pressure testing at 10psi. Old manifolds appear to shrink and cause issues - I have learnt of a couple of tricks in this area that resolve this though:thumbup: TBH - I don't like this design but have learnt to live with it as I like the range of saws!

I experimented with this once and the results were the paint burning and then the metal burning and no decent weld however I have joined aluminium pieces using a kit I purchased. I don't reckon it will work, the large casting will wick the heat away fast and too much heat will melt the casting. Tell me I am wrong:001_rolleyes:

I have repaired similar with liquid glass fibre resin inside the de-greased tank but it needs to be spotless. The outside can be repaired as Stubby says - aluminium plate with JB weld sandwich and mechanical fixing - won't be pretty but it will save a scrap saw!

I'm afraid it does smack of fact, the mileage away from your place of work to book a meal on expenses is correct - not sure if it is 35 miles though. The law is an ass in just about all areas - squatters rights....need I say more:001_rolleyes:

Right - STOP - the markings on the side of the saw are with the LIMITERS in place, you have probably got the limiters removed, it is no wonder the saw is screaming like this - it will be running VERY lean. Take a look at the screws with a torch and if you can see a red and a white plastic cap on the H & L screws they are limited but if they are typical slotted screw heads, they have been removed and using one turn out on each as a starting point will be best. I have seen an MS880 killed in the way you have adjusted the carb!!!

Good call, sounds like the most plausible reason. If the saw has flooded, pull the plug, turn it upside down, turn the ignition off and pull the saw over fast to clear puddled fuel. Heat the plug up on a gas cooker or using a blow torch and than try again without the choke on. I would check the metering valve - something I do when rebuilding the carb:thumbup: Don't use the decomp valve when trying to start - the 365 has a big squish clearance and tends to lack high compression!

The IPL says these are 501 87 68-05 but look damn similar!

You will probably find the coil is limited at around 13.5k so start with the carb rich and then lean out until the Tach goes all over the place which will be around 13.5krpm:thumbup:

The OEM suppliers will buy their bearings from the big suppliers like SKF, and add their mark up. As long as the bearing is specifiied to the same spec - rpm, OD, ID etc, it should be OK but the manuactures do have a habit of having some wierd sizes!