Homelite 775d dies instantly when tilted 90* to bar side.
- Thread starter sliceoflife
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That is fubared
sliceoflife
ArboristSite Operative
As someone who's never had to make that judgment call by looking at a piston or cylinder before I kind of felt that was going to be the response. Thanks.
So I took it out again and finished the last half of the slab that got abandoned and it's running just like it was before.
Making me think if I continue to use it like this and it seizes up every few hours of use, other than the cylinder and piston which are already fubar what's the potential parts at risk to be damaged?
Would it potentially damage the crankshaft, the starter, the clutch, Etc or am I basically just going to be further killing a cylinder and piston that already need replaced?
So I took it out again and finished the last half of the slab that got abandoned and it's running just like it was before.
Making me think if I continue to use it like this and it seizes up every few hours of use, other than the cylinder and piston which are already fubar what's the potential parts at risk to be damaged?
Would it potentially damage the crankshaft, the starter, the clutch, Etc or am I basically just going to be further killing a cylinder and piston that already need replaced?
The 770s, Super Wiz 77 and 80s will all have the same top end. I wouldn't keep using it as is. You may be able to save the cylinder and source a piston. Still need to trace down the air leak causing it. The flywheel side is a standard oil seal, but, if memory serves, the PTO side uses a bronze bushing to seal against the crank. Kart guys have changed this bushing and sized it. Sounded ike a real pain. It also could be leaking at the cylinder base, the flywheel side cover, the reed valve or base of the carburetor.
Either way, pull the cylinder off and learn what you are dealing with. Find IPLs on Leon's chainsaw website. Most parts you should be able to find by a part number search. The hardest ones will be the cylinder, piston and the PTO side bearing.
Either way, pull the cylinder off and learn what you are dealing with. Find IPLs on Leon's chainsaw website. Most parts you should be able to find by a part number search. The hardest ones will be the cylinder, piston and the PTO side bearing.
As far as I am concerned, the 775s are the best of that series. Anything that came after were simply minor refinements.
In your first post you asked if you should return it.
Read post #2 again.
Now is the time for the return. (to fleece bay)
Just couple tips:
I've seen guys overhaul chainsaws, new piston and cylinder and back to the cut test and same thing again. Piston and cylinder damage fast when the saw is placed into a full bar full throttle cut for few minutes. (most generally due to incorrectly adjusted carb)
One of the first things I do with a new to me saw BEFORE I go into it for ANY repairs is remove the muffler and take a very close look at the piston/cylinder. If bad I stop right their. I very seldom take compression readings, BECAUSE I've seen saws with fair compression but the piston and cylinder when viewed through the muffler port being in the severe reject mode. Buying a used chainsaw is kinda like buying a pig in a poke, especially from fleece bay.
When it seized the piston swelled into the cylinder wall, most likely due to running too lean and when the piston swelled into the cylinder resulted in more heat being generated due to piston skirt friction and the saw eating itself. If you had left it setting for about 24 hours it would probably un-seized itself due to the piston SKIRT cooling and slightly shrinking. The aluminum piston skirt expands fast when subject to overheating.
Their are several posts on this site as to why a saw runs lean and destroys it FAST when into a loaded full throttle cut due to overheating.
You need to be aware of such before you start running your next test with a new piston and cylinder or it will happen FAST AGAIN..
I'm not going to tell you to trash the old homelite saw, you may have fell in love with it by now and want to marry her and and sometimes a guy gets so far in he don't want to or can't quit.
Read post #2 again.
Now is the time for the return. (to fleece bay)
Just couple tips:
I've seen guys overhaul chainsaws, new piston and cylinder and back to the cut test and same thing again. Piston and cylinder damage fast when the saw is placed into a full bar full throttle cut for few minutes. (most generally due to incorrectly adjusted carb)
One of the first things I do with a new to me saw BEFORE I go into it for ANY repairs is remove the muffler and take a very close look at the piston/cylinder. If bad I stop right their. I very seldom take compression readings, BECAUSE I've seen saws with fair compression but the piston and cylinder when viewed through the muffler port being in the severe reject mode. Buying a used chainsaw is kinda like buying a pig in a poke, especially from fleece bay.
When it seized the piston swelled into the cylinder wall, most likely due to running too lean and when the piston swelled into the cylinder resulted in more heat being generated due to piston skirt friction and the saw eating itself. If you had left it setting for about 24 hours it would probably un-seized itself due to the piston SKIRT cooling and slightly shrinking. The aluminum piston skirt expands fast when subject to overheating.
Their are several posts on this site as to why a saw runs lean and destroys it FAST when into a loaded full throttle cut due to overheating.
You need to be aware of such before you start running your next test with a new piston and cylinder or it will happen FAST AGAIN..
I'm not going to tell you to trash the old homelite saw, you may have fell in love with it by now and want to marry her and and sometimes a guy gets so far in he don't want to or can't quit.
sliceoflife
ArboristSite Operative
eBay return would be a nightmare at this point. I messaged the seller that it was running well after finding it didn't stall immediately if I rotated it when hot and cutting a few cookies off a log to confirm it worked and left positive feedback already. I'll take your advice in trying not to throw good money after bad though... I'll use the saw as a learning tool, try and diagnose the air leak, keep my eyes open for replacement parts, but not get desperate and overpay... and make sure I've familiarized myself with any potential other problems before putting any expensive replacement parts at risk.
Maybe I'll get lucky and score a non runner with some spare parts and a good top end for a pittance locally... stranger things have happened.
Maybe I'll get lucky and score a non runner with some spare parts and a good top end for a pittance locally... stranger things have happened.
You may be aware of this but anyway.
On the saws that have the adjustable carb jets you need to confirm that you can adjust them for the 4 cycle stroke sound. It helps keep the engine from running lean due to incorrect carb adjustments.
I use a IR thermometer and monitor the actual running temperature when in a full bar loaded cut for extended period of time when I get through working on a saw. I've found that this is more reliable than using the tachometer method because when using a tach someone not familiar with carb adjustment can adjust the carb to keep the max rpm's at specs but the carb may not be adjusted on the rich side and the saw will overheat when in a cut even though the rpms are at or below spec's. (engine is running lean)
This monitoring the temp test is the real deal test that the saw's engine is not overheating due to more things than just carb adjustments.
You can find lots of good info on this site about carb 4 stroking sound, monitoring temp to help reduce chance of running the engine lean etc.
On the saws that have the adjustable carb jets you need to confirm that you can adjust them for the 4 cycle stroke sound. It helps keep the engine from running lean due to incorrect carb adjustments.
I use a IR thermometer and monitor the actual running temperature when in a full bar loaded cut for extended period of time when I get through working on a saw. I've found that this is more reliable than using the tachometer method because when using a tach someone not familiar with carb adjustment can adjust the carb to keep the max rpm's at specs but the carb may not be adjusted on the rich side and the saw will overheat when in a cut even though the rpms are at or below spec's. (engine is running lean)
This monitoring the temp test is the real deal test that the saw's engine is not overheating due to more things than just carb adjustments.
You can find lots of good info on this site about carb 4 stroking sound, monitoring temp to help reduce chance of running the engine lean etc.
sliceoflife
ArboristSite Operative
Appreciate it. Yeah the saw was four stroking when out of the cut and revved... and didn't seem to be overheating. It wasn't even especially hot to the touch when I started fiddling with it to try and free up the piston.
When it died; I assumed that the fuel line had clogged or something and just cut off the fuel supply. Was surprised to find it was actually seized.
I was running 30:1 mix (it was quite smoky)... and the saw didn't sound like it revved up before it died. It just stopped. I just assumed that with the state of the piston/cylinder; when it got heated up the normal amount of swelling made it seize.
I don't know if you read through the entire thread. but the seller did claim he tested all the seals and that there is not an air leak.
Is it possible that the scoring on the piston and cylinder could cause the low compression (saw runs, but is strikingly easy to pull over... way easier than even my 57cc XL super auto); and also cause the saw to possibly seize up when hot for the reason above?
I will be performing my own tests to check for an air leak once the mityvac I ordered gets here; but I'd like to think the seller didn't outright lie to me about there not being an air leak.... and if he just conveniently decided to leave out that the piston/cylinder were trashed because the saw still runs despite it that would be much more inline with what I've come to expect from eBay sellers in my ~25 years on eBay.
When it died; I assumed that the fuel line had clogged or something and just cut off the fuel supply. Was surprised to find it was actually seized.
I was running 30:1 mix (it was quite smoky)... and the saw didn't sound like it revved up before it died. It just stopped. I just assumed that with the state of the piston/cylinder; when it got heated up the normal amount of swelling made it seize.
I don't know if you read through the entire thread. but the seller did claim he tested all the seals and that there is not an air leak.
Is it possible that the scoring on the piston and cylinder could cause the low compression (saw runs, but is strikingly easy to pull over... way easier than even my 57cc XL super auto); and also cause the saw to possibly seize up when hot for the reason above?
I will be performing my own tests to check for an air leak once the mityvac I ordered gets here; but I'd like to think the seller didn't outright lie to me about there not being an air leak.... and if he just conveniently decided to leave out that the piston/cylinder were trashed because the saw still runs despite it that would be much more inline with what I've come to expect from eBay sellers in my ~25 years on eBay.
Agree - if the seller tested vac/press, it seems very unlikely they DIDN'T see the piston damage.
Looks like that model does not have the governor control with the flywheel air vane like the old EZ.
Have you checked the carb diaphragm yet for stiffness? At this point I would leave nothing to question. It has the Tilly HL. right?
sliceoflife
ArboristSite Operative
Carb - Yes tillotson, Haven't disassembled, but I suspect a rebuild was one of the things the seller did... his feedback suggests he bought several parts for this saw just before selling it, and if he skipped a carb kit, I'd be surprised. I'll check after work.
Governor - I'm gonna have to review the parts list/manual to see if/where it is, because I've not noticed one yet looking over the saw. (Looks like there is one... behind the flywheel? Part 16 in this image)
Governor - I'm gonna have to review the parts list/manual to see if/where it is, because I've not noticed one yet looking over the saw. (Looks like there is one... behind the flywheel? Part 16 in this image)
Attachments
I checked Acres site - no governor on the 775.
sliceoflife
ArboristSite Operative
Strange, the parts manual I downloaded from Leon's shows one... Guess I wont know till I take it apart.
I think this metal clip goes to the governor... based on the diagrams in the parts list.
I'm definitely out of my element with saws still... but the more I poke and prod at this thing... the more I think 99% of its problems go back to the piston being trashed. I mean, Pull cord only has about 5-10lbs of resistance (Can easily start it with my pinky finger with the saw just resting on the ground, dont even have to hold it still)... vs maybe 50+ lbs on my slightly bigger g070... which the more I read indicates really really poor compression... which again more I read... sounds like it often is the result of a trashed piston/cylinder...
Honestly what surprises me is that the thing runs. And it actually runs half well... right up until it seized.
On the other hand... You may be able to see in the image how far out the H tune is... I assume that indicates an air leak is definitely possible (The needle is hanging on by a thread, it's almost totally unscrewed).
But on the other, other hand... closing the choke instantly kills the saw... which I'd assume it wouldn't if there was an air leak?
Gonna continue poking and prodding and hopefully by the time I'm confident I've found or ruled out other potential problems; I'll score a decent deal on a replacement top end.
If I could fix this up and have it running strong, then I'd maybe bother fixing the shutoff switch and then start looking for a new starter/recoil unit that doesn't slip and I'd have a pretty awesome saw.
I think this metal clip goes to the governor... based on the diagrams in the parts list.
I'm definitely out of my element with saws still... but the more I poke and prod at this thing... the more I think 99% of its problems go back to the piston being trashed. I mean, Pull cord only has about 5-10lbs of resistance (Can easily start it with my pinky finger with the saw just resting on the ground, dont even have to hold it still)... vs maybe 50+ lbs on my slightly bigger g070... which the more I read indicates really really poor compression... which again more I read... sounds like it often is the result of a trashed piston/cylinder...
Honestly what surprises me is that the thing runs. And it actually runs half well... right up until it seized.
On the other hand... You may be able to see in the image how far out the H tune is... I assume that indicates an air leak is definitely possible (The needle is hanging on by a thread, it's almost totally unscrewed).
But on the other, other hand... closing the choke instantly kills the saw... which I'd assume it wouldn't if there was an air leak?
Gonna continue poking and prodding and hopefully by the time I'm confident I've found or ruled out other potential problems; I'll score a decent deal on a replacement top end.
If I could fix this up and have it running strong, then I'd maybe bother fixing the shutoff switch and then start looking for a new starter/recoil unit that doesn't slip and I'd have a pretty awesome saw.
Attachments
From the photo, it looks like itt may have the governor. Easy way to tell is look at the throttle control. Pulling the trigger "lets" the throttle open, it does not mechanically open it. The governor closes the throttle based on air pressure on the van at the flywheel.
Here's a pic of an EZ with governor. The gov. link is the thin wire and spring on the right of the carb.
Here's a pic of an EZ with governor. The gov. link is the thin wire and spring on the right of the carb.
sliceoflife
ArboristSite Operative
Yep, that's exactly the mechanism on this saw too.
TheShopForestry
ArboristSite Lurker
I wouldn't have trusted the seller that the seals were ok. Did you ever pressure test the saw to make sure he was being truthful?
sliceoflife
ArboristSite Operative
No, I bought everything to do so, but I just haven't yet. I'm planning to pull the carb and turn it into a parts saw for the 775G I had bought initially to steal the top end from... but decided I would rather rebuild it. So before I pull the carb I'll do a pressure test just to see what it shows.
I'm torn on the seller... I mean, the saw was .404 which was nice... It actually does run really darn well; starts first pull most times; even with the P&C damage, pulls the chain on a 36" bar like a boss....
But like you said; yeah he may have cut a couple logs (which the saw will do) and just decided that meant it worked and so he told me he pressure tested it just to shut me up... we'll see.
And the gas tank was a mess. I dumped a good cup or more of sludge and varnish skin (stuff that looks like black tripe)... I don't think the tank had been cleaned at all. That fuel filter is a champ.
No matter what the pressure test reveals, In the end I'll take a couple parts off it for the 775G, stick it on a shelf until the mood strikes me to fix it up again... and chalk it up to a lesson learned.
I'm torn on the seller... I mean, the saw was .404 which was nice... It actually does run really darn well; starts first pull most times; even with the P&C damage, pulls the chain on a 36" bar like a boss....
But like you said; yeah he may have cut a couple logs (which the saw will do) and just decided that meant it worked and so he told me he pressure tested it just to shut me up... we'll see.
And the gas tank was a mess. I dumped a good cup or more of sludge and varnish skin (stuff that looks like black tripe)... I don't think the tank had been cleaned at all. That fuel filter is a champ.
No matter what the pressure test reveals, In the end I'll take a couple parts off it for the 775G, stick it on a shelf until the mood strikes me to fix it up again... and chalk it up to a lesson learned.
