5100 idle?

[timistall]

Any other 5100s slow to idle down coming off WOT? Everything looks smooth under the hood.

 

[166]

Did you check for an air leak?

Have you talked to TonyM or Dave Neiger about this?

Or you could send it up here and we'll check it out.

Steve

 

[timistall]

Did you check for an air leak?

Have you talked to TonyM or Dave Neiger about this?

Or you could send it up here and we'll check it out.

Steve

Thanks Steve...talked to your brother(no air leaks, all linkage smooth) Sent PM to Terry Green. Talked to Dave and richen the L but started to loose throttle response. It just idles down too slow to be safe. Rather buy new carb. than to pay bundles of money for shipping back and forth.

 

[skwerl]

Tim and I were testing our saws since we both got saws in the mail today. His 5100 takes about 3-4 seconds to drop to idle after letting off the throttle. The longer we messed with it, the worse it got. It was as if the butterfly was hanging open although we could physically see it close when the throttle was released. The saw is not safe to run like it is. I was going to tear it down tomorrow and see if I could find anything out of line.

Anybody here have a schematic of the Dolmar 5100 carb so I can make sure all the pieces parts are in the right place?

 

[kf_tree]

could it just be something stupid like a bent linkage? what if you disconect the linkage and rev the saw with your hand on the carb?

 

[timistall]

could it just be something stupid like a bent linkage? what if you disconect the linkage and rev the saw with your hand on the carb?

Dolmar uses thin cable rather than stiff wire. Everything moves freely to the stops.

 

[kf_tree]

Dolmar uses thin cable rather than stiff wire. Everything moves freely to the stops.

then let me ask you this, is the "stop" in the retuned position while the saw is still reving too high? (did that make sense)

 

[166]

Here's the breakdown of the PS-5100s carb.
Steve

 

[skwerl]

Ken,
Yes, we can physically see the butterfly linkage return to the idle stop position. The saw continues to turn about 3K for 3-4 seconds, then drops down to a perfect idle. None of the outer linkage moves after the 3-4 seconds of 3K rpm before dropping to an idle.

Thanks for the PDF, Steve. Hey Tim, can you print that out? My printer is down right now.

 

[kf_tree]

Ken,
Yes, we can physically see the butterfly linkage return to the idle stop position. The saw continues to turn about 3K for 3-4 seconds, then drops down to a perfect idle. None of the outer linkage moves after the 3-4 seconds of 3K rpm before dropping to an idle.

i'm out, good luck

 

[timistall]

Letting off of WOT the saws stays at a high idle for too many seconds and than goes to normal idle. With the cover off all looks normal. Throttle goes to the "stop" but stays at a high idle for a short time.

 

[166]

Here is 3 pictures of the carb area on the PS-5100s, for those who haven't seen this saw.
Steve

 

[166]

Try spraying some carburetor cleaner around the throttle shaft while its running.

 

[skwerl]

Thanks Steve, great pics. Dave just called me a while ago and we discussed it. It's tough because it didn't act up on him up there, but keeps acting up on us down here. I'm no expert on carbs but I've managed to put a couple back together without screwing up, so I'll see if I can find anythnig when I break it down tomorrow.

 

[cuttinscott]

Tim if you want I will send a UPS call tag no cost to you. This needs to be figured out before something happens. I will check the saw out replace whatever is defective and test it then send it back to you. If this sounds good PM me your addy so I can send the call tag

Scott

 

[buck futter]

You are dealing with people that know alot more than I do so if this is worthless rudimentary information please excuse me. The 5100s has a revlimited coil so it would be tough to set the carb like normal. Lets say the high speed was to lean and tach'd out ok because it was limited but when you let off the throttle it stays at a high idle speed until the low speed jet provides enough fuel to slow it down.

Let us know what ends up happening


Lucky

 

[McC]

I've noticed my 5100 doing this also, but I thought it was my glove holding the throtle open. I'll watch to see what you find. It's not running lean.
Scott

 

[skwerl]

Tim and I met up this afternoon and ran saws for a while. The 5100 was still acting up. After 5 minutes of steady running, it would hardly idle at all. The more you used it, the longer it would hang at 3-4K rpm before dropping to idle. The jet settings were much further out than I would have expected. 2 turns on the low speed jet and 2.5 on the main jet. The richer we went, the better it idled but throttle response suffered. Leaning it out less than 2 turns on the main jet and the saw would continue racing when the throttle was released. Leaning out the low end jet made everything worse as well.

I just got done pulling the carb for a quick basic check, blew out the jet orifices and double checked the metering valve height. Everything looked normal and I reassembled. Fired it up and nothing has changed. It's as if the carb is too dam small for the saw. All the linkage movement is smooth and unobstructed (repeating this for the people who want to suggest a sticky linkage problem again).

So as it stands now, we can choose between a racing idle or crappy throttle response. And the overall performance of the saw is pitiful compared to 3 different 346's from 2 builders. I'm pretty much convinced there is some blockage in an internal orifice somewhere. There is little difference between 2.5 turns and 4 turns on the main jet. About 5 turns and the saw dies instantly.

 

[davefr]

This thread got me worried. I just fueled up my 5100 and tried it out and didn't notice anything abnormal.

It returns to idle like most of my Stihls.

Idle speed does seem a tad high because every few second the chain move a little bit but I'm sure it's just the LA that needs a small tweak.

 

[bwalker]

Is this saw stock?
Also have you tried the propane/carb cleaner trick for locating air leaks?