What's on your bench today?

[Rich2484]

There's some food for thought there agg.

 

There is now a fuel spurt format he pipe when taken off the carb. I did replace the fuel pipe and filter with known good ones. So fuel pipe is ruled out.

 

I'm afraid that with the 200t the impulse line doesn't connect direct to carb but connect behind the carb mounting and a seperate Chanel takes it to the carb. Onto the carb boot. But I see what you are saying and I will think of a way to keep it on there while testing. It is doable but will take some fiddling and I may have to use a biro and a marker for the testing. One for the big hole one for the small hole.

 

Given me something to think about there.

 

I need to go and test the carb boot and impulse lines on the carb side. It can be done and it must be the only thing left to try. Every other avenue has been covered. Other than the boot twisting as spud has said and not seeing it due to the carb being in the way.

 

So three areas to test tommorow.

 

Thanks agg. That's a long post.

 

 

Sorry alvin distracted now.

 

You seal area. The pic is a bit hard to see. Looks like the damage doesn't go all the way down the seat. You may be ok with it but you need to use some bearing fit compound when fitting the seals. You may just get away with that.

Edited March 7, 2013 by Rich2484

[GardenKit]

okay, need a bit of advice.

my ms200t is not oiling properly. If you run it up with out the side cover on you can see oil coming out but i presume it is not oiling enough as the chain is running, pretty much, dry.

 

the bar is fairly new and is nice and clean so the problem goes back to the pump or filter.

the worm gear seems to be in good condition.

i have rinsed the oil tank with petrol but that did not help.

 

i have been quoted £40ish:thumbdown: so wanted some advice from the o wise ones. And does the price sound alright??

 

thanks in advance:thumbup:

Take the pump off and blow through the OUT pipe of the pump whilst rotating the pump shaft. You will very likely get a little plug of sawdust pop out of the IN pipe. Reassemble and test. Simples.

[GardenKit]

Instead of testing through the impulse and blocking the boot with a marker why not leave the impulse in place, leave the handle in place and test through a dummy carb.

 

I use an old carb which I have sealed up with JB weld and bedded in a hose tail to connect to the test pump.

This way you can test the boot and impulse tube, as well as the carb mounting plate and gasket.

[Rich2484]

That's a sound idea have a few scrap carbs.

 

So would I need to plug the whole of the carb or could I remove the metering valve and plug the diagram holes after removing the diaghrams and go in through the fuel inlet and just block the main inlet with a plate...?

[GardenKit]

I removed the shafts and butterflies and bonded a tube down the centre of the throat, then filled the impulse passage. Ground the gasket surface flat, and hey presto.

 

I have since ground down the outside to its minimum size so it fits many saws.

[spudulike]

Many thanks people for the help.

 

This is why I love arbtalk.

 

Spud a challenge is not the word I would use but ok.....

 

Ok so I will endevour to answer the above posts so bear with me please.

 

Ok so here is the full story on this saw. It came to me as non running, so a change of carb to eliminate carb issue and it didn't sort it. The saw was not running unless loads of fuel was poured down the carb. A pressure test resulted in the seals being gone. When I started to strip down to get the seals out after I removed them there was significant play in the crank both left and right and a slight knock up and down.

 

So I replaced the bearings and put the crank case back together, before the seals went in the movement on he crank had stopped with the new bearings. There was a small amount of transfer under the exhaust port but NOT enough to worry me about the piston or pot so cleaned it off. Although the comp is a little bit on the low side it's not enough to stop it running.

 

New seals in and tested the saw, both vac and pressure test came beck good. No leaks at all with whatever way I rotated the crank or tried to move it about in any position, I got very anal about trying to move the crank while under the tests and stopped myself from grabbing the pliers to try and wiggle the crank (very technical term that spud ).

 

So assuming that was all fine I re assembled the saw, I then had the running problems I have described. So carb off and two carbs to test this out. All came back with the same problems.

 

So I retested the vac and pressure. The way I go in for the tests is through the impulse line. So spark plug in, exhaust port blocked and carb boot on and blocked. This way as I see it both the impulse line and carb boot are tested for leaks aswell as the caseing.

 

These tests again came back fine. Tank vent vac tested and working as it should. Fuel line also replaced with another to test his out. Again was fine. So pressure tested the carb and it was working as it should. Until....

 

I looked at the meter valve and adjusted this up a bit after checking its alignment with the carb body. It was a little bit low. Put the saw back together and it will run on choke then half choke and start up. It will then run on tickover and rev up and down (and it really revs up well) but stop it and you will get it trying to fire up on tickover but just not manage it. But go to half choke and it will fire up fine then run ok. The tickover is a little bit lumpy but will rev up fine.

 

So after adjusting the metering valve it will run ver well on high revs.

 

Ive looked at the carb boot position and it is right, also looked at the position of the impulse hole on boot to carb and it is also in the right position.

 

The ht lead is also in very good condition with no marks or holes in it, and is giving the best possible spark it can. Opened up the gap on plug a long way and the spark will jump the gap.

 

I've spent the whole day on this saw so its been a loss today. But it's just he way it goes sometimes.

 

And no spark screen in exhaust. I've cleaned the exhaust out aswell.

 

But I've got no intention in giving up on this saw.

 

With what you have done Rich, it should run - have you checked the diaphragm is the right one - I had these issues with one I had in - the central stud was a long one like the one on a 026 diaphragm:001_rolleyes:

 

The only thing to go against this is the fact three carbs haven't solved it???

[spudulike]

<========= This what my 200T crankcase will be needing!

 

All screws are out, I've applied heat around the gasket line, given it strategically light taps with the hammer and I cannot for the love of Arborism split these halves! No fancy tools available and no access to metal/welder.

 

Does anyone have any ideas!?

 

Yeah - take the rubber oiler connector block out and remove the bolt that is hidden by it:001_rolleyes:

[spudulike]

Rich - going back to your carb - I have seen loads of these and I would boil it in the ultrasonic cleaner and this would normally fix it!

 

I had a MS390 like this once, I tried a carb of another MS390 and had the same issue and thought that two carbs wouldn't have the same issue....would they - tried one off an 029 after almost rebuilding the saw and bingo - worked perfectly!

 

Stick it in your US cleaner for an hour and try it again - seen too many of these saws giving this type of issue!!

[Rich2484]

I remembered your post about the diaghram stud being too long before and checked this out aswell.

 

The one thing that and me baffled was after adjusting the meter valve arm the saw ran better as in it actually started.

 

But again with two other carbs one new from a box and one off a working 200t it shouldn't have made a difference.

 

But I lifted the arm up level with the carb body so this would make more fuel let into the system counteracting and air issue. This extra fuel wouldn't have made a difference in the high running of the saw as it would have been burning it by then and would just run rich.....

 

So in theory there must be an air leak in the system and if the crank case is sealed tight and I can more or less rule out a carb issue it must be between the carb and case. This only leaves the carb boot and impulse line. But the boot is on the cylinder nice and tight and I did put some grease around the boot to ensure a good seal was made and the impulse line was also well attached to the cylinder end as I couldnt pull it off when I was stripping the saw down.

 

So that only leaves the carb boot end and the impulse handle end and the hole between carb and boot.

 

Right plan of action for morning, remove the carb and set and old carb up as gardenkit has said, then test this side of the system with pressure and vac. Or just use a bit of grease to temp seal the mating surfaces and try and run the saw to see what happens.

 

Sorry folks a lot of thinking while typing there...

 

Looks like my main areas of concern are the boot and impulse.

[Rich2484]

Rich - going back to your carb - I have seen loads of these and I would boil it in the ultrasonic cleaner and this would normally fix it!

 

I had a MS390 like this once, I tried a carb of another MS390 and had the same issue and thought that two carbs wouldn't have the same issue....would they - tried one off an 029 after almost rebuilding the saw and bingo - worked perfectly!

 

Stick it in your US cleaner for an hour and try it again - seen too many of these saws giving this type of issue!!

 

But again its three carbs. The saws original one, an 020 one new from the box, and a working carb from a working saw that I fixed before (well tweaked to run like a monster before)

 

The original one is the earlier carb that doesn't have the pump in it. But not the 020 carb.