Husqvarna 2100 idle woes

[Woodslasher]

Brief backstory: I fixed a buddy's 61 Rancher and when I returned it he said he had a big husky he wanted me to fix as well. The big Husky was a 2100, "It hasn't been run in awhile so I want you to check it out, no rush." The green weenie was disintegrating and the fuel tank stank of bad gas but aside from that it checked out. I put in a new tillotson carb kit, set the metering lever according to spec, put in a new fuel line/filter, and replaced the weenie. Now for the problem, I can't get it to consistently idle right for the life of me. (Full disclosure, while I was writing this I realized I should check the drum bearing and clutch spring, I'll report back when I do). Either the chain will be spinning (not twitching) or the saw will die. I've thought I had it dialed in, the chain is only twitching and the saw's idled for awhile now and sounds good, then it'll just die. I don't want to pressure/vacuum test it, but I'm not sure what else to do. The top end will sound perfect, it doesn't "scream" or sound funny when it idles, it just won't idle.

 

[Stump Shot]

Brief backstory: I fixed a buddy's 61 Rancher and when I returned it he said he had a big husky he wanted me to fix as well. The big Husky was a 2100, "It hasn't been run in awhile so I want you to check it out, no rush." The green weenie was disintegrating and the fuel tank stank of bad gas but aside from that it checked out. I put in a new tillotson carb kit, set the metering lever according to spec, put in a new fuel line/filter, and replaced the weenie. Now for the problem, I can't get it to consistently idle right for the life of me. (Full disclosure, while I was writing this I realized I should check the drum bearing and clutch spring, I'll report back when I do). Either the chain will be spinning (not twitching) or the saw will die. I've thought I had it dialed in, the chain is only twitching and the saw's idled for awhile now and sounds good, then it'll just die. I don't want to pressure/vacuum test it, but I'm not sure what else to do. The top end will sound perfect, it doesn't "scream" or sound funny when it idles, it just won't idle.

Check for a worn throttle shaft, also the crank seals could be leaking. Pressure test carb and crankcase, check idle circuits under welch plug.

 

[jacob j.]

Also check the tank vent. Those are notorious for the tank venting melting into one piece of gooey rubber.

 

[kneedeepinsaws]

I haven’t confirmed this yet but there are def times when the idle is all over the place and your bac test checks out. before moving on empty the oil reservoir and do the tests again, sometimes the oil tank leaks into the crankcase.
finally if that checks out adjust the metering lever based on the symptoms. If the idle feels really lean no matter how much you tune the low, increase the height just a smidge beyond spec and try again.

 

[davidwyby]

Kind of elementary, but I like to have as much info as I can to combat my lack of experience...I'd get a tach on it.

 

[Woodslasher]

Kind of elementary, but I like to have as much info as I can to combat my lack of experience...I'd get a tach on it.

I don't have a tachometer, I'm a "tune by ear" guy for now.

I haven’t confirmed this yet but there are def times when the idle is all over the place and your bac test checks out. before moving on empty the oil reservoir and do the tests again, sometimes the oil tank leaks into the crankcase.
finally if that checks out adjust the metering lever based on the symptoms. If the idle feels really lean no matter how much you tune the low, increase the height just a smidge beyond spec and try again.

I don't think that's possible on a 2100, but the oil may be leaking into the fuel so I'll check that.

 

[kneedeepinsaws]

I don't have a tachometer, I'm a "tune by ear" guy for now.

I don't think that's possible on a 2100, but the oil may be leaking into the fuel so I'll check that.

Apologies I am not familiar with the 2100 and assumed that it had the same oil tank/crankcase setup as most of the others.

 

[Normzilla]

Check for a worn throttle shaft, also the crank seals could be leaking. Pressure test carb and crankcase, check idle circuits under welch plug.

Im thinking crank seal too. Pto side, was my issue years ago. Rebuilt carb, new fuel line filter etc. First high idle. Then no idle. Crank seal I bet too.

 

[Normzilla]

Also check the tank vent. Those are notorious for the tank venting melting into one piece of gooey rubber.

Good call too. And Aaron eccentric helped me figure out the echo repower kits make an good replacement tank vent.

 

[Woodslasher]

Basic update now that family's gone. I pressure tested the carb, it had a tiny leak. I pulled the diaphragm, blew out the h/l needle holes with a syringe, put it back together in a rush before dinner and it just blew air. I think I forgot to slide the diaphragm tit back into the metering lever, but I'm too tired to go back out and poke at it. In the meantime, I put a new needle in there last time I rebuilt the carb (I think), should I try lapping the seat if my blowing it out doesn't fix the leak?

 

[kanscruzer]

Good call too. And Aaron eccentric helped me figure out the echo repower kits make an good replacement tank vent.

The repower part is to large for a 2100, the 40 year old tank vent will turn to goo. I'm going with crank seals

 

[Normzilla]

The repower part is to large for a 2100, the 40 year old tank vent will turn to goo. I'm going with crank seals

Maybe its a different repower kit or vent. Because I have a echo vent on my 2101. We ran mine up with a vent hose. I can post a pucture later if you like? It works better than the stock ones did.

 

[Woodslasher]

I made sure the tip on the diaphragm was put into the slot in the metering lever and that made it way better, but the carb still gradually loses pressure. Does that mean I need a new carb, I need to lap the needle seat, or ?

 

[kanscruzer]

Maybe its a different repower kit or vent. Because I have a echo vent on my 2101. We ran mine up with a vent hose. I can post a pucture later if you like? It works better than the stock ones did.

Picture ,,, I need a picture. Please and thank you. I'm thinking they had a couple styles.

 

[jacob j.]

I made sure the tip on the diaphragm was put into the slot in the metering lever and that made it way better, but the carb still gradually loses pressure. Does that mean I need a new carb, I need to lap the needle seat, or ?

You might try Mark Heimann's tip of using a Q-tip and rubbing compound. You also might want to make sure that the gaskets aren't leaking. On those older carbs, I use a dab
of Loctite 518 around the metering cover gasket and I make sure the sealing surface for the fuel pump side is flat.

 

[davidwyby]

Submerged pressure test?

 

[davidwyby]

While running spray possible air leak areas with brake cleaner to check for leaks.

what happens if you move it around while idling? Nose up or down?

 

[Woodslasher]

Submerged pressure test?

The saw ran good at all angles, but currently I've pulled the carb and ordered a helicoil for one of the muffler bolt holes. I have done nothing but fight that carb. Sometimes when I put it back together it'll blow air like no tomorrow and not even begin to hold pressure. Other times it'll just slowly bleed down. So far I've pulled everything but the welch plug, submerged it in a jar of solvent, and shaken that jar like a old pickup on a dirt road. I re-assembled it, installed a new needle, new metering lever, set the lever height, stretched the spring a wee bit, and pulled apart/reassembled the carb 6-10 times. Pretty soon I'mma send this carb into orbit (or at least across the shop).

 

[Woodslasher]

Initially the carb pissed air out of the check valve, now it bleeds out of the impulse and check valve. Chainsawr has a n.o.s. check valve kit for this carb, should I get it?

 

[davidwyby]

I think it was @huskihl or @Stump Shot who found surface imperfections in carbs by pressure testing in water and saved them.