Husqvarna 3120XP air leak

[GeorgiaVol]

So I started working on the big 3120XP. Rebuilt the carb, which looked pretty good, btw. Put it all back together, and had serious problems getting it started. It would start with fuel through the carb, but then would race at idle. Dialed the low out 2 or 3 turns out, still races. So, sounds like I have a bad air leak. This time I checked the intake first and everything there looked good. I will figure out a way to do a vacuum and pressure test, but after a little research a bad clutch side seal presents this problem. My question is, what is the part number for the o-ring in the oiler? Or any other suggestions? Thanks in advance guys!

 

[gpzinger]

So I started working on the big 3120XP. Rebuilt the carb, which looked pretty good, btw. Put it all back together, and had serious problems getting it started. It would start with fuel through the carb, but then would race at idle. Dialed the low out 2 or 3 turns out, still races. So, sounds like I have a bad air leak. This time I checked the intake first and everything there looked good. I will figure out a way to do a vacuum and pressure test, but after a little research a bad clutch side seal presents this problem. My question is, what is the part number for the o-ring in the oiler? Or any other suggestions? Thanks in advance guys!

hi, I work at a Husqvarna dealer in MN and the mechanic just found an air leak on a customers 3120xp. the crank grease port was drilled from the inside instead of the outside so there is a direct route for air to leak from the crankcase to the clutch area. if there is this one there HAS to be more.

 

[GeorgiaVol]

On this one it turned out to be the clutch side seal had gone bad.

 

[GeorgiaVol]

Thanks for letting us know though. Good info

 

[Grande Dog]

Howdy,
That's the way they make them because the same shaft goes in their 3120K cutoff. They let the gas / oil vapor lube (keeps aggregates out) the sprocket bearing. For a true pressure / vac test I used to put a couple wraps of electrical followed by a hose clamp to plug the hole in the shaft. if you run it without a sprocket could give you issues.
Regards
Gregg

 

[gpzinger]

Howdy,
That's the way they make them because the same shaft goes in their 3120K cutoff. They let the gas / oil vapor lube (keeps aggregates out) the sprocket bearing. For a true pressure / vac test I used to put a couple wraps of electrical followed by a hose clamp to plug the hole in the shaft. if you run it without a sprocket could give you issues.
Regards
Gregg

You are right Gregg. More checking was done and inside the crankcase on the pto shaft is a metered jet for lubrication. We thought this was a machining mistake.
Randy

 

[logger450]

Howdy,
That's the way they make them because the same shaft goes in their 3120K cutoff. They let the gas / oil vapor lube (keeps aggregates out) the sprocket bearing. For a true pressure / vac test I used to put a couple wraps of electrical followed by a hose clamp to plug the hole in the shaft. if you run it without a sprocket could give you issues.
Regards
Gregg

I was reading your response and I think you might be able to help me. I have a 3120 that was given to me in pieces. Ate a screw. I have rebuilt it an there is a small black hose on the bottom right side of the carb. It is about 4" long and has a brass nipple on the end. My friend that gave it to me said that it belonged to a municipality and had a cut off attachment on it. It does not say 3120K just 3120. I just cannot figure out where that black hose goes .It is a 1996 saw.

 

[Stu in Tokyo]

I was reading your response and I think you might be able to help me. I have a 3120 that was given to me in pieces. Ate a screw. I have rebuilt it an there is a small black hose on the bottom right side of the carb. It is about 4" long and has a brass nipple on the end. My friend that gave it to me said that it belonged to a municipality and had a cut off attachment on it. It does not say 3120K just 3120. I just cannot figure out where that black hose goes .It is a 1996 saw.

I've been having problems getting my 3120XP running and I've been looking for solutions online, I did see a video that showed an older 3120 saw that had a primer bulb on it..?



Could it be that?

Cheers

 

[logger450]

I've been having problems getting my 3120XP running and I've been looking for solutions online, I did see a video that showed an older 3120 saw that had a primer bulb on it..?



Could it be that?

Cheers

I actually talked to the guy that made the video (The Chainsaw Guy) and we both came to the conclusion that it was a primer bulb saw that someone converted to a choke lever.