PhillH

Hi @Dan Maynard yes possibly, it was strange that the plug was sparking when not fitted. Would have expected to see it cut the spark even when ground.

Hi @spudulike exactly, it was misleading hence why I never changed the fuel solenoid at the beginning. Thanks again

Hi @Stubby I think it will be my compression tester as it certainly feels like it has good compression. My arm was hanging off from pulling it over. Thanks again

Hi all, saw is now running. I checked the compression tester on a running saw of similar size. That also had a reading of 125psi so I was reluctant to remove the cylinder. I removed the carb and checked the boot, I could see the inlet side of the piston and it was ok. I checked continuity on the wiring harness and found no issues. After a lot of research on google I found a post from someone stating that the coil will cut the spark if it detects a faulty solenoid so I thought for £20 it was worth a try. Purchased a white solenoid and fuel filter and saw started straight away. It is very strange that there was a spark every time when pulling the saw over with the plug out but it does explain the change in note when trying to start the saw, one second it sounds like it’s about to fire then it sounded different as though there was nothing at all. Anyway it’s a mystery solved, thanks to everyone for there help and I hope my update may help someone else.

I will do as soon as I can, Christmas has got in the way of tinkering time

Both coils are sparking, I do not think there is actually anything wrong with the original coil other then my dad not pulling it over hard enough because when I swapped them i didn’t think the new coil was sparking but after reading a few post people said pull them over quicker which I did and got a spark. swapping the coils makes no difference, fuel in the bore or through the carb air intake makes no difference. Choke on or wide open throttle makes no difference I smoke from the exhaust with a wide open throttle but it does not pop what so ever cheers

I pulled the flywheel off and key was in tact where is should be. How else could the timing be out?

Hi @spudulike thanks again for your response. Christmas has been busy so not had any more time to look further. Had swapped the plug for brand new and swapped back to the old a few times just to try it, spark is viable with both. I have tried two different types of brake cleaner just incase, I have also sprayed it on the floor and lit it with a lighter to check it ignites. I have took petrol from the tank and put it straight in the plug hole, neither petrol or brake cleaner makes a difference even with the throttle wide open. My next steps are: Check continuity on wiring harness from beginning to end. Take off the exhaust and rock fly wheel to see if there is any movement in the rings. Check compression tester on running saw to confirm the 125psi I get on this saw If non of the about show any results then it will be a good clean down and take the cylinder off. Hopefully I get a hour or two over the weekend to take a look. Thanks again.

It probably gets used once/twice a month through the summer. It’s been in use a couple of times a week since September with no problems. I would have thought if it was a fuel or carb issue then it would have attempted to fire from fuel going directly into the plug hole or brake cleaner through the air intake. Spud also mentioned that too. Thanks everyone for your help, have a Merry Christmas

Yes, my dad has owned this saw for the last 6 years and never had a problem until now. It does not get abused and only really gets used in the winter. Thank you for the wiring tips, I will check on those

Thank you @Welshfred I will take a look at that.

Thanks @Stubby I moved it in to see if it had any effect on the starting issue. I will put it back when I do some more investigation.

Hi @spudulike thanks again for your extensive response. I will check the compression over Christmas with another saw. I understand what you are saying regarding the two types of compression testers. I have had the flywheel of and the key is fine and still in tact. I will have a look at rocking the flywheel to see if there is movement in the rings. The coil I removed has the markings 1141 4700 C The new coils is marked with 1141 4701 D (the packaging says 1141 400 4732) I did give L&S engineering the serial number and this is the part the recommended Both coils have the same issue, I did a continuity test between each section but need to do beginning to end. With the throttle wide open I am getting plenty of smoke with every pull, when I remove the plug I am getting smoke coming from the plug hole so it is definitely trying to fire. Thanks again for your help

Thanks @Stubby @woody paul I did have a poke at the rings and they seemed to move but given the fact we have a spark and fuel it leaves only one thing as you both say. I will check the compression tester on a running engine just to confirm it is ok. The saw needs a good clean before I strip it down so it might be a week before I come back with a update. Thanks again

Compression test is 125psi Still will not run on carb cleaner Put new coil on and closed the gap Checked the loom Could it be the rings? We have spark, air, fuel but compression feels good, and it wants to run. We are getting smoke

No mate, fuel was ok and I have put fresh fuel in to rule it out too

Cheers @danmaynard I know the fuel is ok because he had been using it all day and it went in the replacement saw. I have had the exhaust off and all looked ok but as woody said to check for stuck rings. Hopefully a compression test will tell me more. The plug is new, swapped that with the new coil. Thanks for you help

Cheers @woodypaul I have a few things to look at tomorrow

Thanks @spudulike tomorrow I will do a compression test to rule that out. I have had the muffler off and cannot see any scoring. I will try something else instead of brake cleaner too. It is very bizarre as I can see smoke and hear the change in note. I shall report back tomorrow, thanks again to everyone

Ok so here is an update. It was my dad who diagnosed the coil, so I ordered one and fitted it. Found out the MS261 needs to be pulled over fast to get a spark. Still would not run but getting smoke from exhaust and every so often sounded like it wanted to. Spoke to my dad, “what happened” “it sounded like it was running out of fuel, put fuel in and would not start again” I have checked the key - all ok I have refitted the old coil and give it a good pull - it has a spark Tried to start and still the same, throttle wide open and plenty of smoke on each pull but will not fire. Tried brake cleaner again - no start Disconnected kill switch and still the same Compression feels ok Any ideas anyone? Could it be fuel solenoid? Why not fire of brake cleaner. Been used plenty this year with no issue

Sorry mate @Stubby

Let me check and I will report back, thank you @spudulike

Hi @spudulike I gave L&S engineering the serial number and they gave me the part number for the replacement which i ordered. It is weird, I have spark and it sounds like it wants to fire on first 1-2 pulls, smoke from exhaust but then there is a change in the noise and no smoke. Tried brake cleaner straight into the bore and it still would not fire Thank you for your support.

Hi all, I have a 2015 MS261C originally had no spark but that’s because I was not pulling it over quick enough after a new coil. Now it will not start, could it be the fuel solenoid? How can I test the solenoid? Does anyone have any ideas, anything common I should be looking for? Thank you in advance Phill

It could be your own if the dense air is coming down your chimney and vents care left open. Would be worth checking if her stove is lit when you are experiencing this. Smoke test will confirm any leaks