Advice on 051 problems

[Rich2484]

Yeah I heard that to Rich from some bloke who bought a Chinese chainsaw and also recommends using old sump oil.... mind you he said it about all of us....

 

:lol:

 

Just got back in from a call out. A very very ill man from a yacht, was not in a good way at all, got him off and as soon as come back he was off in an ambulance.

 

Will find out tommorow what happened.

[muttley9050]

Had a few hours spare today so started work on the worst saw, hekicoils to recoil case, new recoil spring, carb rebuild, new filters plugs etc. So read up as best I could on tuning carb, screwed low out 1 turn and high out 1.25 turns. Saw started ok but lots of white smoke(lots) . Im assuming I'm running too rich on low screw, but didn't want to damage anything so thought id ask if anyone had a simple description of how to tune and how to know how far to go with high screw. Thanks

James

[spudulike]

Had a few hours spare today so started work on the worst saw, hekicoils to recoil case, new recoil spring, carb rebuild, new filters plugs etc. So read up as best I could on tuning carb, screwed low out 1 turn and high out 1.25 turns. Saw started ok but lots of white smoke(lots) . Im assuming I'm running too rich on low screw, but didn't want to damage anything so thought id ask if anyone had a simple description of how to tune and how to know how far to go with high screw. Thanks

James

 

These older carbs are a bit of an art as the L screw has an effect on the H screw setting ie, if oyu lean off the L screw, it will have the same effect on the H screw.

 

The factory settings are 1 turn on the H screw and 1 1/4 on the L screw so set to these to start.

 

Once set then start the saw and set the idle to slightly fast, start to wind in the L screw and the saw will start to pick up revs or possible start to die, start to turn the L screw back out past the highest revs (it will be something like when you run out of fuel) and around 1/4 turn past this point, the idle starts to hit a point where it gets ever so uneven and sounds....well ...nice:thumbup: best description is a Yamaha RD350YPVS on Allspeeds!

 

Once you have set the L screw, set the H screw to around the 10,000max, if this takes a good size adjustment of the H screw, it can cock up the L screw setting but hopefully it will be very minor - some of the adjustment on these older carbs is just experience and intuition:thumbup:

[wisecobandit]

Factory settings are low 3/4 turn out and high 1 turn out.

Even got the original stickers showing it on one of my saws lol

 

tbh the low setting hardly ever seems to be tweaked far from that.

Just remember these tillotson carbs "flood the carb" to avoid over revving which happens around 9500 rpm.

 

You can block off the governor quite easily to get it to rev higher but remember these are torque/muscle saws and peak power is around 6500rpm.

Edited June 10, 2013 by wisecobandit

[muttley9050]

Thanks Spud, I'll give it a go tomorrow.

I dont have anything to test the speed so have to play that one by ear.

Will let you know how i get on.

James

[muttley9050]

Thanks Wisecoat

My 051 manual says the settings are the same as spuds post, but ill keep what you say in mind. So are you saying i should set h screw to max at 6500rpm?

[wisecobandit]

Thanks Wisecoat

My 051 manual says the settings are the same as spuds post, but ill keep what you say in mind. So are you saying i should set h screw to max at 6500rpm?

 

Trust me the service manual is wrong in respect of the carb settings. All the original stickers even state 3/4 on low and 1 on high on all 051's. Ive rebuilt atleast ten 051's and not one the low screw has been far off 3/4 of a turn. Theres more than a few inaccuracys with the manual and ipl. Even the 075/076 saws only need 3/4 of a turn using the same carb.

 

Set the high speed as a per a normal saw like Spud says but all I was getting at is you can get it to rev higher than when the governor cuts in by blocking it off but you wont achieve anything much in the way of improvement of cutting etc. They are a bit reknowned for ppl tuning them thinking they are 4 stroking but in fact its the limiter cutting in and they are running lean which is why I mention the limiter cutting in at 9500 rpm'ish.

Edited June 10, 2013 by wisecobandit

[mendiplogs]

Thanks Spud, I'll give it a go tomorrow.

I dont have anything to test the speed so have to play that one by ear.

Will let you know how i get on.

James

 

HI JAMES you can have my ms660 3ft bar new chain warm handle low hrs for £600 mate jon

[spudulike]

Trust me the service manual is wrong in respect of the carb settings. All the original stickers even state 3/4 on low and 1 on high on all 051's. Ive rebuilt atleast ten 051's and not one the low screw has been far off 3/4 of a turn. Theres more than a few inaccuracys with the manual and ipl. Even the 075/076 saws only need 3/4 of a turn using the same carb.

 

Set the high speed as a per a normal saw like Spud says but all I was getting at is you can get it to rev higher than when the governor cuts in by blocking it off but you wont achieve anything much in the way of improvement of cutting etc. They are a bit reknowned for ppl tuning them thinking they are 4 stroking but in fact its the limiter cutting in and they are running lean which is why I mention the limiter cutting in at 9500 rpm'ish.

 

Just going by the 051/076 Service document and cross checked against the engine and tach info generic service PDFs I have. I know these can be a bit out on some saws though not sure why your machines are different from these docs:confused1:

 

I have recently had an 026 only run right on 1/2 turn on the L screw so do whatever works - the important thing is to ensure the saw doesn't run lean at max revs and doesnt puddle fuel on idle then stall or smoke like buggary when you yank open the throttle - these old carbs need a bit of a magic touch:lol:

[Rich2484]

Ok. So a bit stuck. Need a 048 carb boot. Anyone got there IPL handy. The part is obsolete. What others would fit?