Was browsing facebook marketplace and saw a $25 backpack blower. It's a Husqvarna 350bt, 50.2cc two stroke. I'm building a gas powered razor dirt bike and I'm planning to use it. Anyways, the engine is not running, we fixed the pull start that was the supposed issue. It has good compression, spark, and I cleaned out the carb. It has no airbox, but I threw on the stock air filter from a predator 79 cc. I have no idea how long it has been sitting, but I was wondering what the best course of action is. Spark arrestor is clean, carb is clean, threw in fresh gas (although it is 87 unleaded so contains ethanol, and oil mixture is not the reccomended 50:1). Even typing this I sound stupid for asking what is wrong. Getting premix today, but if that does not solve, what to do? Thanks.
Husqvarna two stroke
- Thread starter Barîb
- Start date
karl
Well-known member
One thing to note is the engine on most power
blowers are cooled by the big impeller itself.
So removing the engine from the unit may cause overheating , and run poor from not enough flywheel weight.
Anyway, is there resistance when you push the
primer bulb? Fuel is going up the pickup, and
running back down the return?
When the carb was cleaned, fresh diaphragms and gaskets were installed, right?
blowers are cooled by the big impeller itself.
So removing the engine from the unit may cause overheating , and run poor from not enough flywheel weight.
Anyway, is there resistance when you push the
primer bulb? Fuel is going up the pickup, and
running back down the return?
When the carb was cleaned, fresh diaphragms and gaskets were installed, right?
No, I didn't put in new diaphragms or gaskets, but in reality it wasn't that dirty. I directly injected fuel into the crankcase via the spark plug. I rebuilt the carb after spraying down with carb clean. Basically even when directly injecting fuel into above the piston, the engine wont start. Everything is functioning, the gas will not ignite when starter is pulled. Once again, the spark is confirmed firing and I can hear compression.
Edit: Not too worried about overheating, will run open exhaust.
Edit: Not too worried about overheating, will run open exhaust.
Last edited:
Denny
Canned Monster
Check and see if the muffler is plugged up. That is a very common problem with 2 stroke engines.
karl
Well-known member
That's not really a cure, will help a tad, but not make miracles. No air moving over cooling fins= stunted heat dissipation.
Yes, but if the spark arrester was not plugged, I doubt that to be the issue.
So it seems your down to why the prior owner pulled on it until the recoil broke, and sold it.
It's probably junk, just pull the muffler and shine a light at the piston. Any scouring / lines /
stuck rings = junk. Yes it will still feel like is have compression and going to be fine, but just won't run.
If your getting fuel, spark, and the plug is not wet/ fouled, than it has to be the motor itself.
Clean it all up, but if the spark is blue, likely you were sold a dud.
Here is a picture of the piston, noticeable wear, inside of crankcase appears unscathed. I could buy a new piston head for it + rings if that would solve anything. The spark is not blue, it is purplish white, it sparks for sure and the only issue with the recoil start is a screw within that is easily accessible, is loosening, where it was previous held by thread locker. How bad is the piston?
Denny
Canned Monster
Piston is junk! If there are any scratches in the cylinder wall that will catch your finger then it is junk also.
karl
Well-known member
Scrap. You were sold a dud. Sorry.
You will need to buy a whole new cylinder/jug, piston, rings, ect. Likely will exceed cost of new unit.
Maybe questionable ebay knockoffs exist, but i will not advise/ recommend such things.
Give up while your ahead, take the L
Denny
Canned Monster
That was supposed to read finger nail. But I agree with Karl. Just think of it as a cheap education and move on. Where else can you learn a life long lesson for a measly $25.00?
ONE-EYE
Active member
Bro...that piston tho! Sorry man. That's a lot of wear. It looks like it was ran with incorrect mix. Personally I don't run anything with ethanol in it (not even my truck). That stuff wears everything out faster and tends to clog lines and filters. Hopefully you'll be able to find another deal on a better engine.
FlyFrog
Active member
Look for weed wacker/ chainsaws out there hell even another leaf blower, if you cant find anything buy a piston and possibly bore it and sleeve it
Karttekk
Well-known member
Are the rings stuck in their grooves? It looks that way. Just for the heck of it, squirt a small amount of oil into the cylinder through the plug hole then try to start it. Sometimes that will seal the cylinder enough to add enough compression to start the engine. This isn't a fix but a way to diagnose the problem.
Good ideas. If by chance that doesn't do it I'd be more than happy buying a new piston, if it means it will work. This backpack blower is around 350 bucks and I doubt Ill find it for any cheaper. I'm fine taking some time to get this thing running, I am just wondering how much compression (in psi) I would ideally want/ what the lowest compression (in psi) I could run.
FlyFrog
Active member
also check to make sure valve\valves are closing all the way that could prevent it from firing
Karttekk
Well-known member
There are no valves in a 2 cycle. Reeds possibly but no valves.
Karttekk
Well-known member
Don't worry about how much compression, just try the oil trick to see if compression is the issue which I'm sure it is. If you get a piston, hone the cylinder lightly with cutting oil until the walls look clean. Don't over do it. You might need crankcase seals too but that's down the road.
karl
Well-known member
You can't hone a nikasil bore, one the plating is worn through, it's junk.
And by the look of the piston, it's worn through.
That's why I said it needs a new cylinder jug and piston.
