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Post by roodog575 on Jan 16, 2021 11:52:23 GMT -5
Hello, I’m working on cleaning up the second of two EZ Autos I’ve acquired. The first one cleaned up and runs great. The second is racing to very high rpm at start up. I’ve adjusted the carb settings per the manual but I haven’t torn the carb apart. I was hoping to get the same result as with the first saw. No such luck. Duckbills are new as is fuel line. I will be tearing into the carb but was wondering what’s the likely culprit for the super fast idle? Thanks.
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Post by tangobravo on Jan 16, 2021 14:52:20 GMT -5
Screaming about an air leak on the intake somewhere.
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Post by roodog575 on Jan 16, 2021 16:53:20 GMT -5
Pretty sure you nailed it. Besides the carb being a mess, one of the reed valves was chipped on its corner. Ordered a new one. Hope that solves the problem.
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okie
Saw Builder
Posts: 199
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Post by okie on Jan 17, 2021 8:10:45 GMT -5
The EZ does not use duckbills.
Are you indicating that it's high rpms when the compression release button is depressed and you then start the saw and when you pull the throttle trigger it becomes normal run???
If so their is a little slotted shiny screw at the front of the handle to adjust such. Take off the breather cover and you can see the screw. It's a fine thread and will sometimes take several turns out ccw to get a slower response. When it's getting to the correct area a 1/2 turn will be the difference between high and low. Some Bubba has screwed it in to fast because the saw will sometimes start little easier. If hard to start after adjusting to normal start fast rpms install a new spark plug. The adjustment I'm mentioning is in a owners manual.
To start most all EZ's especially cold, but sometimes even a warmed up one, push the decompression button/fast throttle lock in, pull the choke all the way out, pull till you get a pop if the engine is cold, if the engine is warm only pull twice, then push the choke 1/2 way in and start the saw, if cold let it run awhile at 1/2 choke while throttling the trigger until it idles or runs then push the choke all the way in.
Sometimes they will flood but rarely. If you suspect flooded, remove the choke, hold the throttle wide open and drop crank the saw until it starts. (or let it just set for 12 hours)
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Post by edju1958 on Jan 17, 2021 10:36:53 GMT -5
Okie,I beg to differ with you in that EZs do indeed have a duckbill in the fuel & oil caps.
Also,drop starting a saw is a sure way to break the pawls.I've torn a few saws apart only to find broken pawls.At first I couldn't figure it out & then I talked with an old saw guru who enlightened me.There are some saws,especially those with the Fairbanks Morse starters that one can absolutely not drop start,unless you want to replace the cup (good luck with that) & the pawls.The correct way (& probably the safest way) to start a saw is on the ground & held in place.Pull on the recoil rope till you feel the pawls engage,then give it a good swift yank.I know it's difficult to get used to doing this,but it can be done. You are correct about the hi idle screw setting.A lot of folks don't know about that.I had an EZ last summer that I couldn't get the throttle to lock properly.I ended up taking the handle assembly apart & what I'd found was quite interesting.Someone had been in there previously & put a shorter screw in there & the spring that goes over the spring was missing.Fortunately I had the parts on hand from a parts EZ & once put together properly the throttle worked fine.
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okie
Saw Builder
Posts: 199
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Post by okie on Jan 17, 2021 11:55:37 GMT -5
Master saw builder: You are correct: I forgot about the vent duckbills inside the caps. and
I should not have used the term drop start a flooded EZ holding the throttle wide open even with the decompression released. It's not really safe per the owners manual.
Safety wise always put the saw on the ground when starting per the owners manual. (and do the gentle rope pull you mention until the dogs/pawls en-gauge)
Usually if someone has the EZ's fast idle screw set where the saw starts at a high RPM and the new operator tester sets the fast idle screw to normal do not be surprised if the saw is harder to start or floods easier sometimes and sometimes a new spark plug of correct type and properly gapped will correct the harder starting/flooding issues.
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Post by roodog575 on Jan 17, 2021 15:39:04 GMT -5
Thanks for all the replies. I’ll definitely check that idle screw in the handle. This saw has been messed with so it wouldn’t surprise me if that was done in an attempt to make starting easier.
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Post by tangobravo on Jan 17, 2021 19:53:43 GMT -5
Quote from edju1958: The correct way (& probably the safest way) to start a saw is on the ground & held in place.Pull on the recoil rope till you feel the pawls engage,then give it a good swift yank.I know it's difficult to get used to doing this,but it can be done.
Boy did I learn this one the hard way!! Holding my SXL925 in the air and cranking it gave a really nice hard kickback that really loosened up my forearm muscles/ tendons/ligaments. A very deep bruise in my wrist and forearm finally healed up 2 weeks later. I really thought I tore something off in there! I could NOT start any pull rope engine for some time. Place that saw ON THE GROUND, and TAKE UP the slack to compression. Then start the saw with a brisk quick pull. You are asking for trouble any other way!
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Post by edju1958 on Jan 17, 2021 19:59:43 GMT -5
Yeah,now if I can only get my son to start a saw properly,Lol.(he's 26)
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Post by roodog575 on Jan 18, 2021 1:48:56 GMT -5
So the screw in the grip was tightened all the way in. So I’m hoping between that be adjusted back out, the carb being rebuilt with an OEM gasket kit, new duckbills, new fuel line and a new reed on the way to replace the chipped one, this EZ will be running as it should. Thanks for all the input. Fingers crossed.
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Post by roodog575 on Jan 22, 2021 19:51:48 GMT -5
Well, I thought I had this problem solved but after a new Walbro carb kit, fuel line, new reed valve, duckbills and a good cleaning, the problem persists. It started up easy enough but then began to race. It would rev up then shut off. Now it won’t start. I can see light gas seepage from the top gasket of the carb so I’m guessing there’s an issue in there. I used an existing carb that hadn’t been disassembled as a guide when reassembling this one but seems something might be installed in the wrong order? Before I disassemble again, any pointers on what to be looking for? Thanks.
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Post by tangobravo on Jan 22, 2021 20:38:25 GMT -5
Those symptoms really imply an air leak on the intake side somewhere. The fact it speeds up and then stops implies the fuel is leaning out when it stops. I'd be checking the gaskets, alignment, and plastic housings for cracks and any crankcase leaks like a bad crank seal or crack in the case. Hope you can track it down. Could be a diabolical problem not related to these ideas!
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Post by roodog575 on Jan 23, 2021 0:39:33 GMT -5
Thanks. I’ll start double checking everything.
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okie
Saw Builder
Posts: 199
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Post by okie on Jan 23, 2021 6:51:34 GMT -5
Fuel in the airbox needs to be investigated first. Do you have anything that will apply a pressure of 3 to 5 lbs of air pressure to the carb fuel input? If not you need such like a blood pressure bulb with a 0-15 lb gauge or a mity vac that does both pressure and vacuum Do you have the Walbro IPL of the HDC carb from the Walbro site? If not here is a link to their carb service manuals, just click on HDC or whatever type Walbro you have: Walbro Carb service link for manuals, IPL’s, etc Service Manuals - Walbro www.walbro.com/service-manuals/ Here is a link to Leon's video of HDC carb leaking and testing: www.youtube.com/watch?v=n16qcMctvnw&feature=emb_titleAlso lots of good info here about testing a HDC carb for racing and how to use air/vacuum to test. houseofhomelite.proboards.com/thread/10216/homelite-procedure-carburetor-pressure-testingand more info about the carb: www.arboristsite.com/community/threads/who-knows-walbro-hdc-carbs.349023/page-4#post-7455099Do not fool around with the check valve area UNLESS YOU HAVE TESTED AND KNOW IT'S BAD by testing. You can easily ruin your carb. This area was intended to be a NON-serviceable item when Walbro first made the carb.Keep in mind that you have a saw that someone else has been flogging and probably gave up on and them are usually the most troublesome to repair or get back to normal. You might have to remove the carb from your good running EZ and test on the existing surging EZ to see if you have more than just a carb issue.
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Post by roodog575 on Jan 23, 2021 11:48:47 GMT -5
Thanks Okie! This is great info. I’m going to swap carbs just to see what kind of result I get. I’m also going to pick up a pressure tester to make life easier.
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Post by roodog575 on Jan 23, 2021 23:10:05 GMT -5
I’ve built a pressure gauge and watched several of Leon’s videos on HDC carbs. Prior to rebuilding this one, the pressure settled at 2psi from 6psi. After the rebuild, it slowly leaks from 6 all the way to just under 1. This takes a couple minutes.
Per Leon’s videos, I stretched the spring for the fuel metering arm which sits level to the sides of the carb. The check valve is operational. I replaced the slot head screw at the top of the carb with an allen button head and lock washer for more clamping force but I’m still getting a slight leak from the gasket which is easy to see with soap bubbles. The original gasket was in great shape and held pressure better than the new one so I kept it in although the diaphragm material is new.
My question is, is there an acceptable level of leak down? It seems that it is likely air will get sucked in the area that is leaking.
Thanks.
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okie
Saw Builder
Posts: 199
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Post by okie on Jan 24, 2021 6:45:34 GMT -5
My question is, is there an acceptable level of leak down? It seems that it is likely air will get sucked in the area that is leaking.
It's just a little bit bad, kinda like being just a little bit pregnant.
If you tightened the screw down with the single washer and it still leaks the cover or the carb body is severely warped, most likely the little aluminum pot metal cover plate. Someone maybe has tightened it down and one of the little guide pins was not aligned into the body and warped the cover. Take a close look at the guide pins and their mating holes in the carb body. Due to the guide pins being in the cover to hold the gaskets in place during assembly you cannot simply lap the cover using a piece of glass and I doubt if you can use two cork gaskets on the top cover. (unless the gaskets are carefully mated together (stuck together before snugging up the cover) Thick cork will also distort/break if torqued. I've carefully lapped mating pieces using glass plate and 600 grit wet/dry sandpaper.
Install the carb from your other saw onto this surging one and test. This will let you know if your saw's block will operate ok with a good carb. Your major problem with this one can very easily be the engine instead of the carb. (even though you have a leaking carb) If you do not get a good test with the carb swapped, you will need to use your pressure tester and test the block.
Let us know the results.
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Post by tangobravo on Jan 24, 2021 9:53:09 GMT -5
If you have a leaky top or bottom cover plate, you will probably have a wet carburetor box area running the saw. If the needle is leaking it would be flooding the engine and the saw will stop with a very wet spark plug. Be sure you have a functional carburetor as a first step. If you aren't confident in the one on the saw, maybe try the other one as okie recommends.
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okie
Saw Builder
Posts: 199
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Post by okie on Jan 24, 2021 10:57:01 GMT -5
If you have a leaky top or bottom cover plate, you will probably have a wet carburetor box area running the saw. If the needle is leaking it would be flooding the engine and the saw will stop with a very wet spark plug. Be sure you have a functional carburetor as a first step. If you aren't confident in the one on the saw, maybe try the other one as okie recommends. Another hint: If you find that it's the carb by subbing: I've bought used HDC carbs from ebay by doing a saved search and carefully reviewing the results of the search and the purchase. (you will get email's when what you are searching for is listed) You have to play with the search wordings so as to not be getting lots of other stuff such as kits, etc. Sometimes it might be several weeks before something appears. You also have to be very careful when kitting a HDC, some of the kits are just not correct. One example is the little aluminum button on the pump diaphragm is the wrong length. (and therefore the inlet needle arm will not be correct. Also sometimes you can go to the looking for parts section of a site and post and buy a complete saw for parts. Arborist site has such a selection. Guys on the chainsaw sites are more trustworthy than flea bay sellers. I recently bought a Super EZ very reasonable for ignition parts from a guy on a saw site and only parts missing was bar and sprocket which I did not need. He stripped in down (removing the handle) so as it would fit into a Large Flat Rate Box USPS and shipped for about $15 rate. If after subbing the carb you find that you are whipping on a dead horse, you at least have not sunk big bucks into it yet and you have a parts saw. One very important thing is before you start doing a lot of heavy cutting with your EZ's go on-line and review how to PROPERLY tune a chainsaw carb so as it's not running lean. If it's running too lean (mainly due to the carb jets incorrected adjusted) it will not last very long if you get into a long full bar cut. (the block can overheat within 30 seconds and ruin the cyclinder/piston) (and lots of guys are really surprised how fast this can happen) Mainly review how to adjust the H jet for 4 cycling sound.
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Post by roodog575 on Jan 24, 2021 20:27:41 GMT -5
Some success. Between two HDC carbs I was able to build one up that didn’t leak at all during a pressure test. I had luck switching the tops around which is where both were leaking despite fresh rebuilds with Walbro gaskets. I put the good carb into the trouble saw (all red version) but no dice. I suspect bigger gremlins so as of now it’s likely a “learning/parts saw”. My other one, an older white/ red version, ran ok but the carb was all original so I installed the fresh carb on it and got it running nicely so I’m happy with that. Thanks for all the replies. I’ve learned a lot. I can now take the carb in and out of a Super EZ blindfolded.
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