I acquired most of a 385 recently, I found a starter for it, and tried priming it a couple times. I had removed the muffler to check the piston (decent) and put a little fuel in the carb throat. It wouldn't pop ar start up, Put I think I saw what seems like small explosions ( flashes of light) and occasionally it seems like it backfired out the carb. I later noticed the coil gap was too tight so I reset it and tried again, Sane thing, would really fire and backfired out the carb. I havent pulled the flywheel yet
Husqvarna 385xp mystery backfire
- Thread starter david newbie
- Start date
Help Support Arborist Forum:
fly wheel key?
Yup.
Next thing I'd consider is the coil
Can't think of much that would cause that that wouldn't be timing related. Check flywheel key to start with.
Definitely sounds like a timing issue or bad coil. Had a 450 rancher come through the shop recently that was acting very similarly. Flywheel key good, ended up being the ignition coil. Also went through carb and replaced fuel hose, fuel filter, and spark plug.
I re-furbed a Husky 141 that the cast-in key on the flywheel was a factory defect. Went to start and the saw ran backwards for 3 or so seconds. I had to start it a 2nd time just to be sure I wasn't going nuts.
Good thing I did not have a bar and chain on either.
Good thing I did not have a bar and chain on either.
my shindaiwa could occasionally run backwards! Very handy for those of us who sometimes put the chain on backwards
seems like the issue was the coil. I didn't want to do unnecessary hammering on the crankshaft, and I happened to have a 353 in pieces in a box waiting to be saved, so I borrowed the coil off it ,switched the plug wires as the 353 wire was too short.( that's a new thing for me, I just learned that they unscrew!) and put some fuel in the carb and it briefly ran! ( although it seemed to run a little slowly). Thanks for your help!
here's another odd thing, I just rebuilt the Tillotson hs296a carb, with what I think was an OEM carb kit, However, the fuel metering needle that I took out of the carb was a small needle. The kit did not have that, just a large needle , so I looked through some extra carb bits and found a small needle that matched it. Now it seems to be flooding massively!. I bought this saw and a bunch of other stuff from the widow of a retired logger who died and had dementia. Not sure if he had put the wrong needle in? (If putting a carb together incorrectly means dementia., I suspect I must have it too. ). will try again later with the larger needle
Whoops. Maybe my cognitive test is wrong. I had the metering arm sitting on top instead of inserted
Still kind of starts, but runs very slow and dies when I hit the throttle
Compare the old & new diaphragms... sometimes the dimple that presses on the metering lever is different
Is there a fork in the diaphragm end of the control lever? If so, it has to fit into a grove in the diaphragm dimple.
Yes, got it right the second time!
and the rule is gasket first and diaphram second
thenne1713
ArboristSite Guru
CHECK COMPRESSION FIRST, if below 120 most will not run.
Except for the fuel pump where the diaphragm fits first against the carb body and the gasket between it and the cover. Getting this wrong is the cause of many faulty carb rebuilds.
well the last time that happend to me it was the flywheel and the time before that
What saw was this and how did you identify the flywheel problem? What did you visibly see? Thanks
