[lexmarks567]

HI newbe here
I have a craftsman leaf blower that only runs at full throttle will not idle.Move the choke to run it dies.Someone said to replace the diaframe.What do you think.It works 175MPH.Its a blower/vac combo.I do not know the model number.All I can say is thats its a older model

[kiwiguy]

I would start by cleaning out the carburettor, if the diaphragm needs replacing then do it.

Certainly sounds like a fuel issue, but be careful you don't end up spending more on it than a replacement!

[lexmarks567]

Originally Posted by kiwiguy

I would start by cleaning out the carburettor, if the diaphragm needs replacing then do it.

Certainly sounds like a fuel issue, but be careful you don't end up spending more on it than a replacement!

OK I'll try it. I hate messing with 2-cycle carbs.Too many parts.4-cycle carbs are better.

[wacor]

these kind of engines drive me crazy. that is why i now drag wires around and go electric.

you could try running some carb cleaner thru it. not likely to help but simple to try

on my snow blower which is 2 cycle there is a little orifice that plugs up. you can take it apart and not find anything and then put it back together and it is ok.
Edit: what i meant was that it is a very tiny orifice and not always do you see something in it. in my case i took it out and found nothing but it obviously dislodged something in the process.

not sure how one goes about figuring out which screw is the one that is the valve though as there are some adjusting screws for fuel and air that look similar

[thecoalman]

There's two little screws on the carb side by side (should be), They will probably have springs on them. They are for the fuel/air mixture. One is for the high speed and the other is for the low speed. Try turning them about 1/8 a turn in either direction, can't tell you which is which but you should figure it out pretty quick. Be careful with the high speed adjustment, you can increase the power with this but if you lean it out too much you'll blow it up.

[lexmarks567]

Originally Posted by thecoalman

There's two little screws on the carb side by side (should be), They will probably have springs on them. They are for the fuel/air mixture. One is for the high speed and the other is for the low speed. Try turning them about 1/8 a turn in either direction, can't tell you which is which but you should figure it out pretty quick. Be careful with the high speed adjustment, you can increase the power with this but if you lean it out too much you'll blow it up.

The only screw I can adjust is the Idle.the High and low screws have stops on them.They can't be turned

[wacor]

try to see if there is not a model number somewhere on the unit if you have not already. that might help some.

[lexmarks567]

OK Model 517.797941 it says see owners manual for adjustments and mantanece but I don't have one.

Originally Posted by wacorsaut

try to see if there is not a model number somewhere on the unit if you have not already. that might help some.

[wacor]

no luck trying to google that
you sure that is the model?
you could contact sears about it online

[lexmarks567]

Originally Posted by wacorsaut

no luck trying to google that
you sure that is the model?
you could contact sears about it online

www3.sears.com

[thecoalman]

Originally Posted by lexmarks567

The only screw I can adjust is the Idle.the High and low screws have stops on them.They can't be turned

I can say with 90% certainy that the adjustment is what is causing the problem, if you can't turn them....well you're pretty much stuck. What do you mean they have stops on them?

[lexmarks567]

Originally Posted by thecoalman

I can say with 90% certainy that the adjustment is what is causing the problem, if you can't turn them....well you're pretty much stuck. What do you mean they have stops on them?

They have plastic caps over the screws that lock them so they can't be adjusted

[thecoalman]

There has to be a way to remove them otherwise a mechanic would have no choice but to replace the entire carb for something that is very simple to fix.

[lexmarks567]

My guess Is they put the caps on so it can't be adjusted.Only the idle can be adjusted.Cause like said.It will run at half choke and full throttle but dies when you let go.

[wacor]

take a couple of pictures if you can with a close up of the carb.

I know somebody in the area that works on everything and will see if he has any ideas.

like Coalman said i would guess those plastic caps can be removed. it probably destroys them but guessing that the only purpose of them is to detect tampering. but dont rely on me as i am not an expert.