Pressure and vacuum testing a stihl chainsaw
Вставка
- Опубліковано 11 вер 2024
- It is very important to test your chainsaws or weedeaters for air leaks it can make a small two cycle engine hard to start and even score a piston and cylinder[ once damage is done there is no salvaging that piece of equipment] in most cases.........so always pressure test your engines ......Fuel lines........ tank vents......crank cases .......and carbs
Vacuum is measured in inches of mercury. Hg.
Thanks for the video!
Correct ..
@@kevinbolin7665 And you have 2 inches of mercury per psi.
In our shop we are equipped as a machine shop also.... We make the plates and using an adhesive we attach thick rubber to the plates.... So when the muffler comes off we attach the plate to seal it.....Yep there are quite a few different types.......
Well although My boss dosent really own a machine shop anymore . He worked in them pretty much all his life . So as you can imagine how this comment stands out to me as we still use a Lath and milling machine in shop from time to time . These tools have made many adapters or blocking plates as well for pressure and vac testing .I think our last count was 26 blocker plates for various chainsaws and if iam not mistaken 5 clutch removal tools .
Cajun coin hunter I failed to mention as to why we made so many different clutch removal tools in my previous comment. But having your on shop you probably already know of the OEM quality of a few and how often there replaced as a result of failure. LOL….If I had to pick 2 of my least favorite it would be Husqvarna part numbers 502541603 and 502522202 . I bet we have at least 4 of each broken.... and at 20 and 36 dollars a piece …….well it really started hitting the old wallet so to speak . So we just made our on out of old sockets …….There not going to win any beauty contest but they work excellently . Seeing your comment made me realize that I guess great minds think alike. I have personally made about 16 adapters for chainsaws/ trimmers and much like your description I used thick neoprene about 1/8 inch thick with the aid of a little Ply bond as a adhesive . This works great but to be honest as Iam sure you have encountered as well . Chamber ported Cylinders on more modern Saws like Husqvarna can be a pain in the ass as there tamper resistant torx screws often break off upon removal . In fairness there not really intended to be tampered with but the machining methods as well as sealing of said chambers leave a lot to be desired as air leaks are quite frequent on certain models . Husqvarna is quite aware but really coundnt give a shit less . I guess I am a trouble maker but it just kills me to see such quality being pushed ...And as a result I get cold stairs at most service schools …. You know what I find often crazy about these schools is they project the fact that they wont feed back yet are passive upon hearing a honest answer . And when honesty is provided they revert to a defensive mentality to justify shady tactics in quality as well as machining processes . I truly hate dealing with Husqvarna as there completely consumed by sales and opportunity to capitalize on price point shoppers . Often obligating dealers to hold extreme amounts of inventory but Iam likely not telling you anything you already don't know . About 2 years back Jonsered owned by Husqvarna had 6 different sales reps in the course of 4 months as a ploy to obligate pressured sales upon various dealers . And with each change of the new individual there came new stock obligation . This infuriated many dealers locally as you can imagine resulting in the dropping of the line . Husqvarna used it as a pushing method but quickly reverted back to a more pleasing alternative once sales dropped on Jonsereds . Husqvarna is by far the worst company for trying not only to fuck over customers but there own dealers as well ..Respectfully I know it takes money to make money but a penny stolen isn't a penny earned .And just because you can take advantage of someone dosent mean one should …….Husqvarna truly has no shame or concern for anything or anyone but sales .
@@kevinbolin7665 Yep I know the feeling on homemade specialty tools, we have well over a 100 for various things... The old Honda jagger / trash pumps, certain outboard engines, the V4 and V6's ....We straightened a crank shaft on the top part of a V6 one time when it fell at another shop, we saved their butts on that one... I even have a tool that Brigg's don't offer, it's the seat insertion tool like the Techumseh, very easy to make on the lathe...Johnny's dad Frank could make anything in that shop....He is long passed away now, but still with us in memory....I'd love to get you on one of my panels one evening.....I'll have a couple other tech's up also....
Thanks for this video. Having hell with both my Dolmar PS 5100 S and my 346 XP both have just been rebuilt. The Dolmar was ported and runs like a screaming banshee - when it runs. Can't find any reliable local small engine mechs so gonna have to learn it myself.
Friend you are in luck Dolmar just happens to be the brand my boss caries... check your intake boot they often are the source of the problem...pressure testing can reveal the leak.. Also the tank vents swell causing the engine to flood or shut down after a few min of running. You may also wont to check your air filter assembly there will be a donut shaped sponge about the size of a half dollar just under the air filter assembly.{Top of the carb} metering side....it must be clean........on some models like the 510 and 5100 this sponge was solid and it caused problems once it was dirty. I feel its only fair to be honest with you {the carbs on these saws are very sensitive to the gas mix they require } I highly recommend you use a FD rated oil because these saws tac at 14.500 rpms per min. They truly are beast and with yours being ported / I would say you have a real hell cat in your hands when it opens up. Best of luck glad you enjoyed my video ....Please if your curious about FD oil check out my video of why dumb asses and chainsaws don't mix. I even show why its a great oil and give {provide some great information } .....Once again thanks and don't forget to subscribe.
I just installed a new flange coupling yesterday, but I had a hard time getting it in until I removed the muffler and loosened the jug. Maybe I didn't get everything aligned perfectly. Still dies when I spray WD40 into that area. That sponge between the filter and carb was about disintegrated so I didn't even put it back in. Had no idea it was critical - dumbass me. When you say the tank vents swell - I'm not familiar with where the tank vents are or how to check if they are swelled. I'm obviously not a small engine mech. I sure do want to get this saw running - it just flat out screams when it's running right.
I'll check out the oil video later when I get more time. Where are you guys located?
Liberty Ky and the tank vents are hiding under the crank case ....they are on the tank its self toward your trigger assembly. Sadly you have to pull the tank off to have access to the tank vent .There will be a small nickel size piece that presses into the tank you will have to remove also /before you can reach the tank vent. By removing your fuel line from your carb you should be able to pressure test your tank vent .Pump in about 7psi and you should see the pressure bleed off on your pressure guage ....if for some reason your pressure guage stops with any amount of air remaining in the guage you must address the tank vent. Automotive brake bleeding pumps {KITS] work great to check pressure on chainsaws as most have a vac setting as well. You can also get a 12x12 sheet of neoprene {RUBBER} on ebay to make blockers for your carb and exhaust ports .For a better look and understanding of what the items look like iam describing check out my video on pressure testing a chainsaw.
Sorry I was trying to say chainsaw tools /pressure testing {there are 2 parts} The kit you will see in this video {BASIC} can be bought on EBAY just look for Husqvarna pressure testing kits for chainsaws. Although you can see the block off plate made by Dolmar by just rewatching this video and just cut the neoprene in the same way .
Thanks for all the help Kevin!
I really want to refine my diagnostic skills to save as much time as possible in the process of troubleshooting.
One person asked this question but I want to rephrase it and get a positive confirmation that my process makes sense. It seems to me that if you do a vacuum test first and the engine holds vacuum than a pressure test is unnecessary. If you do a vacuum test first and the engine LOSES vacuum, THEN do a pressure test, spraying soapy water, to locate the leak.
Followup questions:
1 - Are there any leaks that will only show up with a pressure test (but not a vacuum test)?
2 - Is it necessary to rotate the crankshaft during a vacuum test to confirm no leaks?
3 - How do I determine if a particular engine has an impulse line? I'm working right now on a Homelite XL Automatic Oiling chainsaw. Is the bar oil pump powered mechanically or through an impulse line? I have the IPL but still don't see how it functions.
Thanks for your time, Kevin!
In the 9 months since I posted the previous comment I've learned a lot more about how small engines work and how to test effectively. Since Kevin never answered my questions I'm going to answer them here for anyone who reads my questions and would like the answers I wanted back then.
First of all, you can certainly perform a pressure test first and there's no reason it won't work to locate SOME air leaks by spraying all around the engine with soapy water. That said, you don't want to perform a vacuum test the same way or you're liable to allow soapy water into the engine.
1-To my knowledge at this time, there are NO leaks that will only show up with a PRESSURE test. EVERY leak will, however, show up with a VACUUM TEST! This is because, by the nature of how a crankcase seal is constructed, the sealing lip faces inward toward the crankcase and can be pressurized (from inside) and will only seal tighter during a pressure test. When performing a vacuum, test, however, there is much less resistance to air bypassing around that same lip into the crankcase. If you look at a cross-sectional diagram of a seal you will easily see what I am describing. The only caveat to this is when the outer circumference of the seal (metal) has been compromised in some way, in which case it will probably also leak when pressurized. For purposes of this discussion, however, I'm referring to the internal seal around the crankshaft itself, which is a form of rubber. This is the surface which will eventually harden and allow an air leak.
2-Athough I don't have first-hand knowledge of this at the moment, rotating the crankshaft through 2-3 full revolutions may very well expose faults in either the crankshaft or the seal itself which only show up when with rotations of the shaft. It does make sense to me and certainly doesn't take much more time to perform since you're in this far anyway.
3-If an impulse line exists there will always be a connection point (nipple/hose barb) somewhere on the crankcase and another connection somewhere on the carburetor. In the case of the engine I was asking about it turned out there is no impulse line, per se, but two impulse passages and orifices leading into the crankcase - one for pressure and one for vacuum. One is for fuel and the other is for the bar oil pump, which is actually a diaphragm-type pump mounted on the side of the engine.
When performing a vacuum test which determines a leak exists, you can locate by spraying a little WD-40 or light oil in the area and see if it disappears into the engine, which then locates the source of the leak. This is the case with crankcase seals, where it's easy enough to rotate the engine so the seal is facing upwards, drop some light oil onto the seal, and create a vacuum to see if the oil disappears.
All other leaks are essentially between fully mating, parallel surfaces with neither direction stronger than the other.
Here is a link so you can see how an oil seal is constructed and why it's obvious it will seal tighter in the pressurized configuration than the vacuum configuration.
www.google.com/search?client=firefox-b-1-e&q=cross+section+drawing+of+crankcase+seal
i know this is old but if you have disassembled this far to do a vac and press test wouldnt it be smart to replace the seals no matter the outcome because you already have it apart?
If its your own equipment {Yes} no doubt as long as the piston and cylinder haven't been scorn . A customers well.......You may need to ask if they wont the work done on such a old piece of equipment . As shop labor often can be 60 plus dollars and hour .So seals ,labor, etc could become expensive .
Thats what i have found, i can pressurize and it holds but when i do a vacuum, it is much more obvious
Excellent.
Good video .
Thanks for the video, I am in the midst of redoing a few saws of my own. I will do these tests, but I am also replacing 2 top ends. DO I need to plug the oiler places on a Stihl 075, 051 which I am doing now? Or if it gets to where I am servicing my 026's or 044, 660,,,,,,, same question.
Hi Kevin where do you purchase the block off plates
Dealers / and some are homemade as well ....But Husqvarna offers them on ebay .....sadly they can be hard to find because of demand . If your having a problematic piece of equipment just order a piece of neoprene rubber and cut out a wedge to place behind your carb and muffler .
@@kevinbolin7665 how would you attach a nipple to the rubber on the carb side to hook the vac up?
Hi, great video! If a saw has a vacuum leak, but no pressure leak, how do I know where the leak is at (impulse line, intake boot, gaskets, seals)? Is it usually crank seals that show this symptom? The saw is a Stihl MS260, and the rpms drop when the bar tip is pointed down, and increase when pointed up. Rarely stalls at idle, though. I first thought intake boot, but assumed that the saw wouldnt hold pressure if that was the case.
Its likely a faulty seal or a mating surface causing this to happen as the outer lips maybe fine but inner have been hardened by heat . The internal pressure of the saw pressures the seals against the crankshaft once a pressure tester is used causing the lips to contour to the crankshaft where a vac against the faulty seal {lips} would then be capable of pulling the seals inner lips that have hardened away allowing a decrease in vac pressure on a vac tester .
Note / This is indictive of a saw that only is being provided enough oil to fuel mixture to run and even after the repair of {replacing seals and sealing of mating surfaces } You should richen the carb slightly . I have found that many chainsaw and trimmers carbs are built cheap and as a result they don't provide truly enough oil / fuel to vital parts internal to modern equipment for adequate lubrication .
@@kevinbolin7665 Thanks for your answer. So you would try replacing the crank seals before intake boot, impulse line etc.?
Love to know where the adapter plates can be had...
You can purchase most on ebay by looking up[Husqvarna chainsaw pressure kits] In doing so you need to find{ chainsaw tool box kit compression tester wrenches plug wrenches for Husqvarna } typically it cost 89.99 and the adapters are included [not all but most] / don't be fooled you also need a good vac tester to .
If you would like to see other tools that you will need check out my other video [Chainsaw tools/pressure testing] there will be 2 videos and can greatly help you if you wont the proper tools to repair a chainsaw or trimmer.
I usually make my own using a gasket as a pattern and cut it out of a piece of aluminum strip available at hardware or farm stores. Put a piece of inner tube on the inner side glued to the aluminum with rubber cement.
Do you offer this pressure test, and indicated repair, to the public? Can I send you my lightly used 38 year old 028 for testing and repair?
Can you test threw the Impulse line? I saw a video of someone doing that, and rotating the engine....I thought it had to be threw the Intake?
Yes / its ok to check threw the impulse line as the pressure should be the same with no leaks . By rotating the engines crankshaft you insure the seals are uniform and tight in contact with the crankshaft as well as bearings performing as intended with no lost motion to cause a leak around the seal due to wear of the seal lips .
Hi Kevin. I am a recent subscriber and enjoy your channel. You clearly have experience and expertise with the Dolmar brand and maybe you can give me some advice. I have a PS510 which has given be reliable service for the past 10 years. When I went to fire it up this spring, it was a no go, wouldn’t even fire. Tried some starting fluid and fuel/oil mix in the cylinder and through the carb and got nothing. I have 115 psi cylinder compression. I have good spark. I have new fuel and air filters. And I have rebuilt the carb. All without success. Where would you go from here? I pressure tested the carb before reinstalling it and it held 7 PSI. I use pure gas-no ethanol at a 50:1 mix. I’m not sure what the nest step should be. Hopefully with your Dolmar experience, you can give me some useful advice. Thanks.
how much would you charge me to make the ones i don't have i see 3 or 4 that i don't yet let me know if you can
should we do the vac test first?, then pressure with soapy water, wondering if it sucked in soapy water on the vac test afterwards, just a thought
Well you make a great point and in truth you have the right idea ....But in honesty if you had a vac or pressure leak it would be best to remove both seals and spray carb cleaner into the bearings that would then be exposed ..Note if there was a leak I would recommend first blowing off the seal areas and check the crankshaft for loose motion as often a seal leak in these saws is often due to the failure of a bearing or the hole it resides in becoming distorted . Witch is often the cause of a seal leak ........But keep in mind also equipment that is stored may become affected also due to old gasoline taking its toll on the seals and gluing them to the crankshafts .....this affects carbs as well as fuel lines and impulse lines as well . Witch is why I stress with any repair on a Chainsaw or trimmer do a vac and pressure test .
I was thinking the same thing...or just pressure test, wipe the soak off, Then vac test.
Yes ...blowing off the soap before vac testing would be ideal but not really needed as often if there is a vac leak by rotating the engines crank it will expose its self .
do you need to put your piston in a certain position when doing test,either all the way up or down in cylinder wall?
Often all the way down ….Although you should pull the starter rope slowly turning over the piston a few times ensuring the seals lips are indeed sealing …..Aged seals can grip the crankshaft perfectly intel being turned to another position .
What about making my own adapters. Perhaps use a gasket as a templet, machine or 3d print.
hey Kevin what is the part number for the dolmar pate?
I will get this number for you...
There are two/ the first is neoprene and the numbers are 944.603.160 {these are typically used on the muffler side but can be applied to the carb side as well .} The next is 944.603.170 This is metal with a place to insert a small hose that can be placed on to pump up the pressure or vac pressure . You will need to purchase both if you don't have a spark plug vac and pressure adapter . They are idea if you own a 510 0r 5100 Dolmar.
Thank Kevin
Welcome...
Some one should invent a hand saw to cut down trees.
Akgunhalil