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Post by jselden78 on Jan 3, 2020 21:23:10 GMT -5
Although I am a man of an unprecedented number of talents, the are of taking a good cell phone video has eluded me. None the less I have included one with this post. I had time tonight to get out in the garage and tinker with the 925 I have pieced together from several parts saws. It cranks but that's about it and seems to be pulling air from somewhere. Carb tests fine as does the line into the tank. I hooked up to the crankcase to do a pressure test and found what I thought to be quite odd. (I will finish the post but I do believe the root cause of this reading just hit me) anyway at low pressures as you can see in the video it drops quite fast. Once I get above about 8 or 10 though it seals off quite well as the video will show it holds 20psi with no problem but won't hold 5. I switch to vacuum and it will absolutely hold nothing. I haven't hit it with soapy water yet because this just seemed to be strange to me and I even thought soapy water may not reveal it since it doesn't leak at high pressures. I will admit I have not had to test many of these so I thought maybe someone that has might have an idea of what is happening here. www.flickr.com/photos/138659658@N05/shares/06ttN9 |
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Post by edju1958 on Jan 3, 2020 21:52:21 GMT -5
Those were some cool tunes playing John! It seems to me that I read of someone else having this same exact problem,but for the life of me I can't remember where it was,or what the cause was.Sorry I can't help.
Ed
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Post by jselden78 on Jan 3, 2020 22:37:39 GMT -5
So I was right when writing the first post in that I thought of what the problem was lol part of it (possibly all) was self inflicted here. The adapter I grabbed to connect my pressure tester to the crankcase is on that is very easy to install and I made the same mistake probably a year ago but since then I have forgotten. That adapter has a check valve in it so when the pressure gets up around 8 psi I am no longer putting air in the crankcase, I am simply checking pressure in my line from my tester to the cylinder which does nothing to test the saw. Removed that adapter and went with another and found the intake throat or neck was cracked. I circled the crack in the pic, if you zoom in you can kinda see it. This is the second one of these out of several of these saws I have brought back to life that this neck has been cracked. I am not sure if the crack is part of the reason the original owner decided to put the saw up because he could never get it tuned or if I am cracking it by overtightening the bolts on the carb. Either way I guess I will be in the market for one of these. I may have one in my parts here but gotta get some rest as I will be back on the backhoe engine early in the morning. P.S. that was Pokey La Farge playing in the background. I must admit sometimes I am torn between whether its the saws or the music that has be getting away to the garage when I can escape the pressures of every day life lol. www.flickr.com/photos/138659658@N05/shares/tMrX85 |
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Post by onlyhomelites on Jan 3, 2020 22:56:35 GMT -5
Nicely done! There was a Service Bulletin at some point about this very problem. If I remember correctly, the damage was usually from over-torquing the carburetor screws.
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Post by jselden78 on Jan 3, 2020 23:32:33 GMT -5
Nicely done! There was a Service Bulletin at some point about this very problem. If I remember correctly, the damage was usually from over-torquing the carburetor screws. Is there a way to search the service memos by model or pretty much just have to go through and read them as they are posted? Just to be clear I am not complaining about how they are now. This forum and your website I believe are the most organized that I have seen and other forums could take lessons from here. I just haven’t read all the service memos and didn’t know if they were grouped or could be search by model is all |
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Post by edju1958 on Jan 3, 2020 23:57:06 GMT -5
If you're following the torque specs set by Homelite for tightening down the carb I wouldn't think that would cause a problem.Of course not everyone follows the torque specs,especially on something so trivial as a carb,but I guess it does make a difference. Ed
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Post by onlyhomelites on Jan 4, 2020 0:19:53 GMT -5
UNdee70ss and I have both "threatened" to do a master index of the service bulletins for easier searching. I'm not sure about him, but I have not started that project yet.
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Post by jselden78 on Jan 4, 2020 7:35:36 GMT -5
UNdee70ss and I have both "threatened" to do a master index of the service bulletins for easier searching. I'm not sure about him, but I have not started that project yet. I would imagine that project would be quite an undertaking. I think just having them available as they are is fine. |
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Post by jselden78 on Jan 4, 2020 7:39:27 GMT -5
If you're following the torque specs set by Homelite for tightening down the carb I wouldn't think that would cause a problem.Of course not everyone follows the torque specs,especially on something so trivial as a carb,but I guess it does make a difference. Ed
I haven’t run across a torque wrench yet that would fit on that bottom carb screw during installation in order to reach the specified torque for that application |
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Post by onlyhomelites on Jan 4, 2020 10:54:43 GMT -5
Exactly! The reality is the plastic/Bakelite was too thin around the inserts and left little margin for error. I choose to look at gasket compression...if the edges of the carburetor gasket start to fold, it's tight enough.
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Post by edju1958 on Jan 4, 2020 11:21:28 GMT -5
Sorry,I was thinking of another brand that uses top mount carb bolts rather than the Homie sideways mount. Ed
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Post by undee70ss on Jan 4, 2020 21:31:57 GMT -5
UNdee70ss and I have both "threatened" to do a master index of the service bulletins for easier searching. I'm not sure about him, but I have not started that project yet. I haven’t started either, was also planning on making bulletins by saw family. |
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