What's on your bench today?

[spudulike]

Busy day today, the Wolfman picked up his 084, his bloody KM100 Stihl had packed up yet again, quick fiddle with the tappets and bingo - running again:thumbup:

 

Been working on a MS440, the carb was plugged with a piece of sealent used on the brass plug and welch plug. Put it in the US cleaner and then resealed the welch plug.

 

The saw has been ported, not a massive amount to be done as Stihl haven't left much on the table. Opened up the piston windows to increase flow, widened the exhaust port, lowered the transfers and reshaped the upper transfers to improve scavaging. Have modded the muffler, looking at the front muffler cover for modification or may fit the dual port Stihl unit.

 

Fired it up today and seems a bit more lively - just needs tuning after the muffler is finished!

 

From the pics below, you can see what has been ground out - all ringed in red:thumbup1:

[Ricbob]

My dads mcculloch mt300x strimmer.

 

symptoms: rough ideal and hesitant pick up.

 

First tried fresh fuel, cleaned air filter, check spark plug condition and gap.

 

No change so went to tune carb, couldnt get it to ideal right so started looking at the fuel system. found a small crack in the fuel line where it connects to the carb. with enough line to play with i just snipped off the bad bit and refit. It started up much easier so i retuned the carb and it now runs like a good un!

 

Just in time for the F1 too, winner

[Rich2484]

went through all the work saws today. 088, 048av, 034 x2, 026, ms260 x2, 200t. found a few problems with some but not all. one 034 was missing the plate behind the bar. the 026 is running rough needs a carb. all sharpend and checked and now ready for the winter.

[JAMIE1]

Just picked up a box of 024 026 bits at carboot sale, only wanted the top cover and air filter cover, all the rest was nuts, bolts an cobwebs. Get home and have a proper look and there are 3 good condition used cranks, How do i tell if these are 024 or 026 cranks?

[WoodED]

had to change clutch springs on my ms361 cbq again and also fitted a new flywheel to my colleuges ms261.

gave my 346xp, 576xp and my ms200t a clean up and greased the needle bearings. also gave the 12 inch tunnisen chipper a good greasing.

[Rich2484]

This 026 is starting to do me in.

 

Stripped and cleaned today. Checked impulse line and carb boot. Both ok. Carb is clean as a whistle, comp at 160 cold, spark is good.

 

Now she will run if both high low screws are out as far as they will go but at full throttle she will rev up and down. At factory settings she will run on idle for a few secs then die.

 

I have got it to the stage of running on tickover then the moment the throttle is touched she dies. Will not start with throttle held in either. If I hold the choke closed pull throttle then release choke she will rev like crazy then die.

 

Any help?

 

 

Oh and it has been bugging me today, what running problems would mean the welch plug needs sealing off?

[spudulike]

This 026 is starting to do me in.

 

Stripped and cleaned today. Checked impulse line and carb boot. Both ok. Carb is clean as a whistle, comp at 160 cold, spark is good.

 

Now she will run if both high low screws are out as far as they will go but at full throttle she will rev up and down. At factory settings she will run on idle for a few secs then die.

 

I have got it to the stage of running on tickover then the moment the throttle is touched she dies. Will not start with throttle held in either. If I hold the choke closed pull throttle then release choke she will rev like crazy then die.

 

Any help?

 

Oh and it has been bugging me today, what running problems would mean the welch plug needs sealing off?

 

Easy bit first, the leaking welch plug basically fooks up the idle as the fuel is pulled up through the plug rather than past the L screw so you get a varying idle but it wont effect the high speed that much. A missing welch plug stops the engine running.

 

 

Your problem sounds like severe lack of fuel or massive air leak, a few things to try: -

 

1) check that the pumping membrane is next to the carb body and the spacer gasket is next to the cover

 

2) check the spacer gasket on the diaphragm side is between the carb body and the diaphragm

 

3) Check the metering arm height - I think the 026 carb has a raised bit around the metering arm that the arm should be level with.

 

4) check the pumping membrane flaps have no holes in them - put it up against a bright light to do so.

 

5) Has the carb been in the ultrasonic cleaner - you may have the main jet blocked - look at my earlier thread this weekend on the MS440 - it had similar problems and had a plugged main jet.

 

6) Have you blasted carb cleaner down the H and L screw holes and noted if the cleaner comes out of the low speed and high speed injectors on the bottom of the carb bore/throat/choke.

 

7) Check the breather - loosen the fuel cap when running - does it help?

 

8) Have you pressure checked it, you may have a very shot crank seal as it is giving similar symptoms to a Jonsered 630 I have which had a completely shot crank seal.

 

Thats a first pass - let us know how you get on. On any saw that I am not happy with, I pressure and vac test it as it cuts out all those bits that are hard to inspect and can give issues. Other than that, you could try a known good carb to eliminate the carb.

[Rich2484]

Ok I will give it a good going over.

 

My vac/pressure tester has broken (I dropped it on the floor and the pressure gauge hit the floor and broke)

 

Waiting for new one.

 

It's definatly nothing to do with a supply of fuel from the tank. All is good there.

 

Carb has been us cleaned.

 

Will check the membrane with a light.

 

Without a tester I can't check the seals so until I get one that will have to be the last test.

 

I did try and get a 260 carb on but stihl being stihl have changed the carbs just enough that they look the same but the high low screws have a raised block around them that means it won't fit. If that makes sense. I havnt got another 026 carb to try.

 

Again excellent advice spud and I will be trying these things out tomoz before ordering a new carb.

[elfinwood saws]

Spent the day in the shed out of the rain, had a tidy up and dug out a Pramac p4500 diesel generator that i took in p/x that did not run, it has a yanmar L70 single cylinder diesel engine, it wound not start and no smoke when cranking over! First problem i found was the airfilter was in back to front making it impossable for the engine to suck air in. Tried cranking it over still no smoke so no fuel reaching the engine! next i found a intermitant fault on the wiring to the fuel cut off solanoid, fixed this cranked it over still no smoke. Next fault i found was the injector pump was not pumping so off it came and dismanteled on the bench found a few little bits of crap in the one way valve in the injector pump, but it back together and tested it on the bench and all was good so hopefully when i refit the injector pump in the morning all will be well and i will have another working genny.

[Rich2484]

026 is running.....

 

Yay jumping around the shed with joy.

 

Thanks for the info spud.

 

Went straight for pressure test by blanking off intake, exhaust, spark plug, and no leaking anywhere.

 

Took the carb apart and spent time inspecting it and low and behold the metering arm was lower than the raised ridge so when pressing it with a finger it worked but the diaghram wouldn't. Raised it up, put saw back together and runs like new.

 

Again thanks spud, always good to have a bit of backup when needed.

 

I would love to plug your head into a laptop and download the info you've got in that brain.