The previous post on 064 with leaking seals brought this question to mind.
Years ago, I got a ‘free’ Poulan S25 Micro I think it was called. (Free is another story, we all know how that goes.) Ran it for years. Eventually, it would start, rev up for 1-2 seconds, and die. Would not restart unless it sat for 10 seconds or so. Starting on WD40 or ether, same story, so not suspected lack of fuel delivery, but did occasionally show flooded condition after it ran that second or two.
Wasn’t worth fixing, I had other saws. However, I have wrenched all my life, taught small engines and motorcycle classes, and the male ego couldn’t deal with being defeated by this little saw.
I did all the normal tests, nothing but frustration, let it sit for months until a new brainstorm, try something else, let it sit again. Eventually I surrendered and gave it away for parts. That was 5 or 10 years ago.
It always seemed to me that it started and ran, delivered too much fuel, flooded, and died. I thought too much pulse pressure was causing too much fuel pressure. Something had to do with pressure build up because the time was very consistent; Start, rev, hold high idle for maybe one second, and die.
Not in order, but I suspected ring blowby, replaced rings (aftermarket of some sort, but seemed correct), did carb cleanings, new diaphragms, checked popoff pressure, increased and decreased that with spring changes, tried many H & L screw settings, compression test, pressure vacuum the crankcase, checked the seals, cleaned points, plug of course, magneto gap to flywheel, disconnected kill switch wiring, ran with and without muffler.
Has bugged me occasionally ever since. What in the world did I miss?
kcj
Years ago, I got a ‘free’ Poulan S25 Micro I think it was called. (Free is another story, we all know how that goes.) Ran it for years. Eventually, it would start, rev up for 1-2 seconds, and die. Would not restart unless it sat for 10 seconds or so. Starting on WD40 or ether, same story, so not suspected lack of fuel delivery, but did occasionally show flooded condition after it ran that second or two.
Wasn’t worth fixing, I had other saws. However, I have wrenched all my life, taught small engines and motorcycle classes, and the male ego couldn’t deal with being defeated by this little saw.
I did all the normal tests, nothing but frustration, let it sit for months until a new brainstorm, try something else, let it sit again. Eventually I surrendered and gave it away for parts. That was 5 or 10 years ago.
It always seemed to me that it started and ran, delivered too much fuel, flooded, and died. I thought too much pulse pressure was causing too much fuel pressure. Something had to do with pressure build up because the time was very consistent; Start, rev, hold high idle for maybe one second, and die.
Not in order, but I suspected ring blowby, replaced rings (aftermarket of some sort, but seemed correct), did carb cleanings, new diaphragms, checked popoff pressure, increased and decreased that with spring changes, tried many H & L screw settings, compression test, pressure vacuum the crankcase, checked the seals, cleaned points, plug of course, magneto gap to flywheel, disconnected kill switch wiring, ran with and without muffler.
Has bugged me occasionally ever since. What in the world did I miss?
kcj
