Need help - Fuel/air screws and setting idle on 032

[OneStaple]

Hey,

I'm working on getting my "new" 032 going and could use some help with fuel/air adjustments and idle issues.

When I first got this running, it had been sitting for a few years (due to a broken impulse line). With that fixed, it ran with smooth idle (although the chain moved at idle), but bogged down after a few seconds at full throttle.

I lowered the idle speed to a point where the chain wasn't turning. The chainsaw no longer had a problem with full throttle, but it sounded like it was about to die at idle.

So I decided to go to factory specs. I reset the high and low speed fuel/air mixture screws to one turn out, as per the manual (and the side of the chainsaw). The high speed had originally been at 3/4 turns, and the low speed had originally been at 1.5 turns. Full throttle still runs smoothly except for the occasional quick dip in rpms. I haven't tried it while cutting anything yet.

From what I know about carbs, I would have set the low speed to a leaner mixture, which would make the chainsaw run faster (up to a point). The problem now is that I can't set the idle screw so that the chain stops moving (I unscrewed it to a point where it no longer contacts the throttle plate on the carb).

The only solutions I can think of are to make the low speed screw set richer to slow the chainsaw down at idle (I'd think this wouldn't be ideal though), or that something like the springs are worn out on my clutch (is this possible to check?) so it engages too early.

Anyone have any ideas? I'm not sure what to do. Any help/suggestions are greatly appreciated!

Thanks,
Tyler

 

[Lakeside53]

If you can make it idle down until it quits, but the chain runs, then yes.. clutch springs... but if that isn't enough - look carefully at the impulse hose connection at the carb - they leak. And for $2.25, I'd just replace it.

 

[OneStaple]

I can't idle it down to where it quits, so it must not be the clutch springs.

The impulse tube was bad (split in half) when I got it. I replaced it with a good one from another saw. If the impulse tube wasn't good, wouldn't it run poorly at full throttle too, as not enough suction would get to the carb, the diaphragm wouldn't open enough, and enough thus fuel wouldn't get to the cylinder? Lakeside (or anyone else) - any chance you could explain how a bad impulse hose would affect the performance? Maybe I'm just missing/not understanding something.

My brother mentioned that maybe the butterfly valve in the carb wasn't closing or something so that too much fuel/air was getting through at idle. Is this ever an issue, or is there something similar that could happen that would allow too much fuel/air through?

It seems like the low speed fuel/air screw is set at least close to the correct setting, because it "idles" and accelerates smoothly and doesn't give off any gas when idling.

Any other suggestions?

Thanks,
Tyler

 

[Ray Bennett]

I had a saw that the chain kept running like you are saying and all it needed was a little grease on the needle bearing, Did you check that?

 

[OneStaple]

I didn't check the needle bearings (I assume you mean the ones near the sprocket/clutch). I'll have to check that tomorrow and let you know the result. But shouldn't I still be able to set idle so low that the chainsaw quits running if that was the problem?

I've worked on motorcycle engines before, but this is my first chainsaw, so there may be a few things (like the needle bearings) that I'm prone to overlook.

Thanks,
--Tyler

 

[Lakeside53]

Generally you are correct about the impulse hose, but in an 032 with a full tank it can siphon down to the carb...enought to fool you.. and suck a small amount of air into the engine through the impulse.

Yes, if your throttle plate doesn't close properly.. the saw can rev too high at idle.

If it's not your carb, then you have a air leak. With the L screw out 1.25 turns (or so), you should be able to turn the LA out until the saw stops.


There is a small plastic insert to the right of the boot behind the carb... Is yours in place? Do you have the support ring the throat of the boot?

 

[OneStaple]

I pulled the clutch off tonight and greased the needle bearings. They seemed to be in decent shape. I doubt that's the problem, but I'll try running the saw tomorrow.

When I was first trying to fix the saw, I disconnected the boot from the cylinder head. It has the metal tightening ring on the throat. When I put it back on, I also coated the connection area with silicon grease (I've done this on motorcycles before) to discourage any air leaks at that connection. I had also pulled the carb off, but didn't put any silicon grease where the carb connects to the boot. Perhaps some air could leak in there? Is it worth pulling the carb off and putting some silicon grease on that connection?

Lakeside - for the "small plastic insert to the right of the boot behind the carb," am I looking for the black rectangular piece that's just above where the impulse hose comes through the wall and attaches to the carb? If so, that's in place.

I also played a little with the throttle trigger and where that connects to the carb body. It feels like that's moving as far as it should. It doesn't really turn past where it naturally stops, although if I put a tiny bit of pressure on it (closing the throttle plate in the carb) and then try to turn it back the other way (open the throttle plate), it catches a little and feels like I had wedged the throttle plate closed. So it seems like that's working as it should.

At this point the things to look at might be a leak at the impulse tube and a leak at the carb/boot connection. Any other suggestions?

Thanks,
--Tyler

 

[Lakeside53]

If I'd run out of options, and had tried another carb, then I'd pressure and vacuum test the entire engine.

No, grease is not worth putting on either end.