What's up with this carb?

[John in MA]

I just finished replacing the gaskets and diaphragms in an HS. Didn't touch the welch plugs. The saw started right up, idles great, has loads of top-end power. However, I found that I could screw the high speed jet all the way in and it would still run. Sounded pretty lean to me, but still... It ran properly on about 1/2 turn out--not a lot to me.

I've never tried this on another saw. Is this normal, or is this a problem? Aside from putting in new welch plugs is there anything else to check?

 

[tony marks]

yep john ,i ran into something similar today when adjusting my solo 634.
im a little gun shy on leaving it too lean. but it really dont like the h to be any more than 3/4 turn out. it will run all the way in also. probably not for long tho.
in any case its a small saw and wont be used in heavy cut . so i hope itll be alrite.

 

[Jacob J.]

<p>did you replace the inletting needle and lever? Did you take the adjustment screws out and run some carb cleaner through the passages? Did you check the fixed jet for carmelized fuel?<p/>

 

[oakman]

"carmelized fuel"?????
is that the same as carmelized onions? or apples?

john, usually this will indicate a damaged hi speed needle/seat. inspect the needle carefully under a magnifying glass. occasionally you may see damage to the tip or sides. also put a mini-mag up to the seat hole and look at it under the glass. usually the aluminum of the carb body will get mushroomed out from a heavy hand on the adjustment screw, with hardly any or no damage to the screw itself. if thats not it, then fuel is getting by someplace else. i really don't pay too close attention how many turns an adjuster is out. thats not how you tune a saw. 1 1/2 to 2 turns out is an initial setting to get it running, hopefully. then tune by ear. if you tune by how many turns you are inviting trouble. your statement that it is proper rich at 1/2 turn out would lead me to believe the high speed needle seat may be damaged/mushroomed out. ocassianally the tip of the screw will break off so cleanly you can't see it with the naked eye.

 

[John in MA]

Thanks for help. Are those like Carmelized nuns? Oh wait...

Haven't looked at the seat yet, but the needle is sharp and smooth. No problems there. Everything was sprayed with carb cleaner and blow out with shop air.

I'll take look at that seat when I replace the welch plugs. Tillotson also suggests replacing the nozzle check vavle cage. What the hell is that?

 

[Fish]

And I thought I was kinky, but dipping nuns in caramel is
too much!

What saw is this on? I have seen a few saws that have their factory settings at 1/2 turn out on both, also have seen
a few that set @ 3/4.

 

[user 2993]

The carb on my 090 does the same thing. I rebuilt it the same way. It has had me equally worried, but I've checked the sparkplug and compression a couple times and all seems well.
It is a Tillotson HL 244a, which appears to be not the original carb, as the adj. screws don't line up with their access holes- lots of fun when the saw is jumping around on the ground with a 42" bar
Good luck,
George

 

[user 2993]

Oh, the nuns are healthier for you than the gas because they are actually caramel-lite. But they can be habit forming.

 

[John in MA]

This is actually on my 111S. It dried up while I was using smaller saws over the winter. Idle is fine at one turn out, just like Tillotson says. High speed seems right at around 1/2. At least it's not an air leak or something. I can live with it if it doesn't start spilling fuel or anything.

 

[Stumper]

I had a similar problem on the carb in my Husky 268XP. Worse though since it alternated between running ,and starving. The problem was a malfunctioning check valve.

 

[John in MA]

What check valve are you talking about? One of the fuel pump ones, or the mysterious one that I've never been able to ID or have described to me?

 

[Stumper]

The mysterious one. It is in the carb body. I would explain further but that is all I know. The mechanic who does my work pulled it and replaced it-he saved the old part for me and said it was a pain in the butt to get out. It is a little brass doohickey. Sorry I'm not more help-have you looked for a carb schematic?

 

[John in MA]

OK, now I get it. It's a little brass thing with a rubber diaphragm.

So guys, is this a commonly available part? Anyone have a list of PNs?

 

[Dave]

John, clearly this saw is junk and cannot be fixed. Haul it down here, I'll give you ten bucks for gas and buy you lunch.

 

[BillW]

Tillotson HS Carb

The Service Trouble Data says either the 7/32 diam. nozzle welch plug OR nozzle check valve cage is not sealing. Which HS carb do you have? there are several diff kits available. Bill

 

[stihltech]

carmel

Actually, the carmel he is talking about is the junk that collects in the fixed jet from old fuel. Have cleaned a few jets that cured a lean problem. That is why you start with a smaller drill when opening the jet.
But then, I have been known to hack a carb now and then.