spudulike

Thanks Martin, this is my 357XP, I was pissed off that it got beaten by 0.4 seconds on three cuts by a 560XP running a shorter bar so we took 0.5mm of the outer Piston crown and cylinder base which upped the compression to 200psi. The saw already had widened ports and modified uppers and lowers plus a loud muffler mod. Goes rather well now - [ame] [/ame]

Wondered why you had gone so quiet Martin, 2nd steam train - what is it this time?

After pulling the saw over on choke, was the spark plug wet or dry? If it is dry, even after 10-15 pulls, the issue is with the carb/fuel system, if it is wet then the fuel system is probably OK but do turn the saw upside down and pull it over so you clear any flooded and puddled fuel from the lower crankcase. The spark sounds a little strange, I recently had an ignition module fail on a 372 - pretty uncommon for these SEM units. One thing to do is to make sure the coil is damn close to the flywheel - I set this with a business card and that works for me. Try a different spark plug but it isn't often this is the issue. If you get stuck and need help, PM me.

I was surprised I didn't hear more about the 346XP - glad you like it:thumbup: On sprockets etc, you could fit a 13" bar on the 346XP and then an 8 pin rim, that will get it going a bit but make sure the oiler is turned right up, that chain will spin a fair bit faster. If the saw can pull decent revs in the cut, without bogging, the depth gauges can be lowered but bear in mind, the chain may be rougher in the cut causing more vibration. The last thing you can do is square file your chain which makes it super aggressive if done correctly. You need the correct files to do it and getting the angles right isn't easy - I have not done this before anyone asks! You can also try changing the angle of the cutters on your chain - like some do on softwoods!

Hi Charles, the 372 is a tried and tested formulae that many I have done saws for really rate

The only saw I have known backfire like this was a Stihl 028 and it scared the bejusus out of me - just wasn't expecting it! It sounds like the flywheel key has failed and the ignition is well in retardation. Barrie has listed the other possibilities, the ignition coil modules have some trick advance retard circuitry in them and it could have gone tits up. A good way to see if the flywheel has slipped is to pull out the sparkplug, allign the coil with the flywheel magnets (it will pull it in to position) and then place a screwdriver end on the top of the piston and turn the flywheel anti clockwise and see if the screwdriver rises a little before falling. There should be circa 27 - 32 degrees of advance on the flywheel position when gripped by the magnets to coil before TDC. Sorting out the flywheel key, if it is that, will be a PITA - I am doing this in a big way on an old 066 at the moment - it may be possible to re key it if you are inventive or just get a new/secondhand one.

I have PMed the OP, I should be able to offer a fix and also more importantly, do all the checks and set up to ensure it doesn't happen again straight after repair which I have seen before on other "repaired" saws but hasten to add - not mine:001_rolleyes: See what happens if you contact Husqvarna but am happy to resolve this issue and hopefully find out what caused it and for a reasonable price.

I thought they had shipped them all out to India and China - we used to have one in our tool room:thumbup:

It is possible that the L screw is set badly rich and this is affecting the richness of the H screw at the top end. Set both on 3/4s out and try that and be prepared to wind the H screw out a little more as standard is 1 turn on each. The valve you are talking about is probably the high speed check valve - some times these can be driven out and replaced and sometimes not - a good Ultrasonic Cleaner will often resolve the issues as it will cavitate clean all the crevices in the carb. It is also possible the metering arm is set too high or the needle is leaking a little - is the metering arm spring inserted correctly?

Thanks Martin, it sounds like the saw is very low hours, that will mean it may not be fully run in yet and the rough surface of the bore will cause friction plus compression will be a little down. My own experience of these smaller engine saws is that the L screw takes a fair bit of time to get spot on. Too rich or lean and it will bog in the mid range and become bad to use. Being a new saw, it may well be set a tad lean on the L screw just to meet the US EPA figures, you may find opening up the L screw (counter clockwise) 1/8th turn may restore the low speed torque. You can buy the splined adjuster for a tenner or another novel way is to fit a spade crimp connector on the end of a flat blade screwdriver and push this in to the adjuster and it should effect an adjustment. I wouldn.t try to modify anything without putting some hours on it as Tanaka kit is generally well made and should work OK. It is possible an exhaust modification may help in time but try tweaking the carb before getting silly with it. I ended up making adjustments and test cuts with a small Tanaka I had a while ago and found a sweet spot....eventually:thumbup:

Get a picture up and lets have a look at it!

Hopefully you have taken note of things like where the ring ends are and not taking the ports to within 2mm of the piston skirt edges!

You devil you:lol:

I forgot the bit about becoming obsessed about porting everything you have including the leaf blower:blushing:

Those stickers are an infringment of my civil liberties, I will contact my EU representative if I find one on my equipment:blushing: Think the missus may have something to say about that as well:lol:

A good list Barrie, it is amazing how much you actually do when you go over a machine:thumbup:

Interesting............. I was basing my measurements on the 357XP we did that had 0.5mm pop up so reckoned 0.75mm should bring the compression up a bit:thumbup:

There are a number of benifits, generally you can get an older saw running as fast as a later generation saw. You could port say an MS200T and suffer less fatigue as it will take less effort and time to cut larger limbs or fit a larger bar so you don't need to haul up a larger saw quite so often. One major benifit is doing work with a 60cc saw where normally you would be up a size to say 70cc or even much larger saving your body suffering the fatigue a larger saw would have on it. On the other side, you have to consider the H&S if others use your saws, they are noisier and thirstier to use but are a lot more enjoyable to use that their non ported equivalents. Others will have other opinions

Sorry Wes, we have something known as the metric system in the UK:lol:

Looks OK to me, what is it like lower on the skirt? The brown bit is blow by and not uncommon and OK if not heavily carbonized. Small marks are OK.

Fuxtech, is this a wind up:lol:

Cheers Martin, still have to sort out the ignition timing, that is a real headache, I believe 22.5 degrees of advance is around right and will need to key the flywheel. Your bit is relatively straightforward, take around 0.75 off the outer crown and bottom of the cylinder - must check the position of the first ring before we machine anything. Currently cleaning it for spraying as the paint is pretty crappy. Once we do your bit, I will measure the port durations and get cutting:thumbup:

54mm in answer to our conversation, we go mad on this one:thumbup:

This is probably one for my new porting thread but yes, I have done some of this type of tweak, done respond well and others don't. You have to be careful to get the degrees right as too much and you run the risk of some spectacular mechanical carnage!

Yup, think that is about right - just waiting to see what state it comes back to me in, think I may just sharpen the chain and check it out in front of him before I give his cash back:lol: