Where is the fork that connects to the needle? (not shown in pic) Need to know which model carb you have.
Homelite Chainsaws
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ML12
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Since that photo was taken I've torn down and completely rebuilt the saw with new seals, gaskets, piston rings, etc. So the cracked hose has been repaired. When I rebuilt the carb I didn't change the needle and seat, which evidently needed to be swapped out, so I will do that.
I also doubt that I was the first person to take the saw apart as there were a few 'custom touches' on some of the fasteners and a missing circlip in the gearbox.
steved
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I have a newer (probably less than seven year old) Homelite 42cc saw...it has been fairly reliable for light stuff, I've only had to replace the coil (and that was a while ago).
I just recently started getting a high rpm no-load surging. Put some load on it, straightens right out. No issues with power...
What should I look for to address a surge?
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I just recently started getting a high rpm no-load surging. Put some load on it, straightens right out. No issues with power...
What should I look for to address a surge?
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Clean the air filter to make sure it's flowing enough air and if it's still surging, open the high speed needle (the rear one) a little like 1/16 of a turn out.
Does the saw return to idle when you let go of the trigger is it still running fast and returning very slowly? If so, you likely have an air leak.
steved
ArboristSite Guru
I did clean the air filter, it wasn't too bad...just a block of foam. I would need to look, I'm not sure I have the drivers to adjust the carb (I think they are something other than a typical screw driver)?
I would need to pay attention to the spool down...I don't remember if it has a lag. I did try tightening the carb mounting bolts but they were tight.
If I get home early enough tonight, I will check.
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The only numbers on it are 5-458 on the choke side, then on the mixture screw side it says HDC 2.
On the top it says homelite, HDC, textron division port Chester Ny USA.
That is all.
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Here is the fork, tell me if it looks right. The bends look wonky to me.
I couldn't find a parts list for the HDC-2 but most all HDC's use the metering plate gasket you were using directly to the right of the carb.
The metering lever looks good to me. They are generally clinched onto the rod in the metering plate but I have run those and HDB's with no issue with them loose.
Check to make sure there is a tiny brass cup plug in the hole circled in the pic.
If it was mine I would be spraying carb cleaner through all the orifices paying special attention that fuel flow under the pump diaphragm flaps are clear.
I would also pressure check the carb to make sure it's not leaking anywhere.
I know it basic but I've done it before, is to check the order of the gasket and diaphragm on the pump side and make sure the needles are set at 1 turn out.
I also turn the idle speed way up when trouble shooting.
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I went to look at it again but cant tell if there is a plug in there or not. Is it as simple as just poling a wire in there and making sure the hole does not go all the way through?
HDC-2 parts list and diagram.
https://www.leonschainsawpartsandre...dc-1_hdc-2_hdc-4_carburetor_ipl_24324-a_2.pdf
I find HDC's finicky to set on this series. The low circuit is fed through the H as far as I can tell. Mine don't run at 1 and 1. I am usually closer to 3/4 and 3/4. I set the H first then tweek the L. They can start to load up in a hurry if the L is too rich and the idle is too high. Turning up the idle past a point causes them to pig out and die. I try and tweek the L and idle to get the chain to spin then richen up the L to adjust the idle back down. Any adjustment on the H moderates the delivery to the low cicuit and you are back to the start again.
I've had a couple that are tough to seal at the impulse/carb/block. There isn't a lot of real estate there to work with being the impulse on the carb is so close to the edge of the body. I like to add Motoseal around that area.
I've had a few where the base gasket is not sealing well also.
I've had a couple that are tough to seal at the impulse/carb/block. There isn't a lot of real estate there to work with being the impulse on the carb is so close to the edge of the body. I like to add Motoseal around that area.
I've had a few where the base gasket is not sealing well also.
Had an HDC-4 handy tonight.
As I mentioned (if it helps), the L is fed from the H. I've included a pic and drawing to outline the circuit with the correct gasket in place. There is an additional impulse activated by a bypass in the throttle shaft that feeds the L circuit. It opens up when the throttle is cracked off of idle. It acts like an accelerator pump dumping fuel into the L circuit. You can run fairly lean at idle but still accelerate well with the extra fuel upon throttle. Finicky. Make certain there is an additional impulse hole in the gasket to feed the circuit. See the photo showing the brass screen/port on the rear of carb body. I am no expert here, so some of what I offer may not be entirely correct. Fire away.
Metering circuit gasket
Brass plug with small inlet hole (as Tim mentioned). This is fed impulse from the block when the throttle is cracked. It is sealed off when the throttle is at idle. But, I do think they can cause havoc if the idle screw is set high as they likely begin to leak enough to cause them to load up at idle.
Red is the fuel circuit. It is fed to the H through the circuit plate hole and follows the route as indicated. Blue is the additional throttle impulse on the L circuit when accelerating. There is a bore in the shaft that aligns with the passage when the throttle opens.
Make certain that impulse hole is also fed through the gasket so the blue circuit is activated. You can check the circuit is clear by blowing on a sealed fuel line against the brass screen or passing WD-40/carb cleaner. It won't pass when the throttle is closed, but when opened it will feed through that brass plug (with small hole) beside the metering chamber at the L circuit. It will push additional fuel into the venturi upon throttling.
As I mentioned (if it helps), the L is fed from the H. I've included a pic and drawing to outline the circuit with the correct gasket in place. There is an additional impulse activated by a bypass in the throttle shaft that feeds the L circuit. It opens up when the throttle is cracked off of idle. It acts like an accelerator pump dumping fuel into the L circuit. You can run fairly lean at idle but still accelerate well with the extra fuel upon throttle. Finicky. Make certain there is an additional impulse hole in the gasket to feed the circuit. See the photo showing the brass screen/port on the rear of carb body. I am no expert here, so some of what I offer may not be entirely correct. Fire away.
Metering circuit gasket
Brass plug with small inlet hole (as Tim mentioned). This is fed impulse from the block when the throttle is cracked. It is sealed off when the throttle is at idle. But, I do think they can cause havoc if the idle screw is set high as they likely begin to leak enough to cause them to load up at idle.
Red is the fuel circuit. It is fed to the H through the circuit plate hole and follows the route as indicated. Blue is the additional throttle impulse on the L circuit when accelerating. There is a bore in the shaft that aligns with the passage when the throttle opens.
Make certain that impulse hole is also fed through the gasket so the blue circuit is activated. You can check the circuit is clear by blowing on a sealed fuel line against the brass screen or passing WD-40/carb cleaner. It won't pass when the throttle is closed, but when opened it will feed through that brass plug (with small hole) beside the metering chamber at the L circuit. It will push additional fuel into the venturi upon throttling.
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Ok, there definitely is not a brass jet in that hole but based on the IPL provided above for my carb it appears it is in the air horn.
There definitely is no impulse port in the gasket for that, is it as simple as cutting a slot in the gasket to connect the dots? I dont think there is a second port in the intake but I will need to check again.
Obviously we have identified a problem, but would that cause it not to fire at all?
It will only fire on prime, it wont even try to run off the carb alone.
There definitely is no impulse port in the gasket for that, is it as simple as cutting a slot in the gasket to connect the dots? I dont think there is a second port in the intake but I will need to check again.
Obviously we have identified a problem, but would that cause it not to fire at all?
It will only fire on prime, it wont even try to run off the carb alone.
Good stuff Cory. I am gathering some good info here.
The HDC 44 I am looking at has a brass cup plug in that hole. There is no hole in it.
Kevin,
OEM gasket looks like this one. The channel is there to serve both screened and impulse ports in the carb adapter
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Ok, that doesnt look like the one I made or the one that was in there that I copied. I dont remember seeing a second impulse port in the intake, I will have to check again tonight.
If your block is the same there's just the one port at TDC in the block but it does have a groove around to the screen.
Pic of the block and the gasket I made for it in the PDF files below.
If you have a printer, those come our actual size when printed at 100% to use as a template.
Ditto. Much appreciated. Currently fighting a fixed jet HDC-40 here. Just out of the USC with a kit on the way.
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I took delivery of these tonight. The big homelite is an XL 925. It runs but needs the fuel line in the tank. Anyone have a source? The echo is a 452vl for anyone that was asking.I scored this pile for $20 I believe the big saw lower left in the photo in an XL925. How can I verify? The sticker is missing all but XL and 5.
I wont lay hands on them for a couple weeks, my father in law that lives 4 hrs away in Maine made the score for me.
How did I do?
And that is a Lombard, a lightning to be exact which is cool. There is a very clean super XL automatic in one of the cases. Plus a regular XL12 plus a whole pile of top handle XLs.
Pretty excited. I would consider trading off the echo, and the Pioneer 600 if anyone is interested in them. Would be looking for big old Mccullochs mostly.
id be interested in info & pics of 600.
not in any rush.
couple runnin macs id consider trading.
not in any rush.
couple runnin macs id consider trading.
ML12
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Got the XP-1100 running, thanks to the manual from @undee70ss. Turns out the saw like about 1/2 turn on the low, 1/2 turn of the "air screw" plus some idle stop, and about 1-1/4 turns on the high-speed side. Its very, very picky on the settings, and a little bit either way and it won't run. The idle sounds too high but I swear its because I'm used to my Mac's and Huskys that have a low, thumping, idle.
What I will say is that it is hard to start. Because of the accelerator pump, it seems like you have to pull the choke, pump the throttle ~4 times then pull it over with the throttle open. Otherwise you'll pull all day long and get nowhere. I guess its like an old car in that respect.
Its got heaps of compression, and its not even broken in yet. And it oils like mad. Just need to get some 1/2" chain and get it in some wood.
*** yes I know the air filter cover is the wrong color and the starter should be a different style, but those are the parts I had.
What I will say is that it is hard to start. Because of the accelerator pump, it seems like you have to pull the choke, pump the throttle ~4 times then pull it over with the throttle open. Otherwise you'll pull all day long and get nowhere. I guess its like an old car in that respect.
Its got heaps of compression, and its not even broken in yet. And it oils like mad. Just need to get some 1/2" chain and get it in some wood.
*** yes I know the air filter cover is the wrong color and the starter should be a different style, but those are the parts I had.
