Husqvarna 265 SP problem...need help

[roundhead]

I come across this problem every so often. It happened with my 395 also. I try everything I know to do but cannot get the saw to pop. I have fuel, compression, and spark. timing is lined up correctly. I dont really have the tools to do a leakdown test properly. I tried putting air into the impulse line into the crankcase and putting some soapy water over the crankcase seals but I dont think it was really filling with air.
anyway my question is, what should my next step be? replace the seals? I dont want to invest in or make tools to seal it up properly. I hate to throw in the towel and take it to the shop
thanks
UPDATE: Husqvarna 365 SP

 

[rupedoggy]

When I can not get a saw to "POP" the first thing I do is squirt a little mix right into the carb throat. If it is flooded anyway, it won't hurt anything. Next remove the spark plug. Is it wet or dry? Ground plug against the cylinder and check for spark. Then it could be low compression but I can generally tell low compression by feel. Look at this chart and proceed. Mike

 

[B.C.]

Had a few poulans I was working on recently and one of them was a real bear to get to pop, pretty well same scenario, had everything but no pop. Trying to get it to pop with a prime or a starting fluid with lubricant is a good way to start. Your carburetor settings on some saws, at least on these two poulans, had to be pretty darn close before they would really fire. A prime should circumvent any carb settings though and let you see if it will indeed pop / run at all. As rupedoggy noted squirting a little mix gas right into the carb is a great way to see it it will indeed fire. Then you can adjust the L screw in or out about 1/2 turn at a time and see if you can get it to run and tune from there. I often jack the idle up a bunch at first just to get it going and then adjust it down while adjusting the L screw back and forth until I get a good idle and then do the H from there.

Had a little extra trouble with the one poulan because I must have flooded it with too much prime and then I pulled on it so much I hurt my shoulder. Had to let it sit and then when I came back after a half hour or so it fired right up.

 

[pioneerguy600]

Agreed, priming a problematic starting saw is my first step as well, it often gets the saw started even if its only a couple seconds. From that initial startup much can be determined but by priming one can get around a bad carb or air leaks , they can be determined after a saw starts. If the saw starts and quickly runs out of gas, stops then it is likely a fuel delivery issue, bad fuel line,filter, impulse line or a carb that needs rebuilding as the diaphragms are hardened. A partially plugged up screen in the carb will usually allow a saw to start and idle but not allow the engine to rev up, a cracked impulse line will do the same thing often, a cracked or broke off fuel line won`t pull fuel very well, this gets tricky some times if the line is broke/cracked in the tank itself, the carb can still pull fuel if the fuel level is above the crack but when the level changes and the crack is exposed to the air then air will be sucked into the line. If the engine will not start after a prime then it either does not have spark at the right time or its flooded, test for spark and at the same time it will be evident if the engine is flooded, while pulling the recoil to test for spark often fuel droplets will be spit out the sparkplug hole. If the engine has spark then drying out the engine and reinstall the plug should get it going again if proper starting procedure is used, if the engine floods again and did not start then the carb needs attention. Bad seals and air leaks won`t cause a engine to flood, they cause such a lean condition it can make starting them difficult, if the engine starts with an air leak it will run at a high idle as the fuel to air ratio is off, more air than fuel causes higher RPM with a loss of power on top end. Pressurizing the engine by any means and applying dish soap around leak prone areas will most always locate air leaks by blowing bubbles, only case I can think of not finding a slight air leak this way is if the seal is only leaking under Vac, pressure is causing the seal to push outwards and seal whereas under Vac the seal is sucked inward and loses contact to the crank causing a leak.
With all this said and done I firmly believe in doing a Vac and pressure test on every problematic saw as I have encountered so many that exhibited sporadic malfunctions that one would be chasing their tale and throwing part after part on the engine trying to guess what might be wrong instead of diagnosing the real problem right off.

 

[B.C.]

I have to agree with Pioneerguy on the pressure tester, since I've gotten one & use a soap spray you can really narrow things down a lot faster. A lot of times I find leaks at a carburetor boot if the saw has one. Or if there is a plate that connects the carburetor to the cylinder. Sometimes the crank seals leak and that is a big problem, you can't have that, running it like that will eventually destroy the saw even if you can get it to run, or any leak that causes lean really. You can put the tester on the inlet of the carburetor and crank up to about 5 to max of 10 psi to see if your pump diaphragm or needle holds. It should. If it doesn't you need to kit or work on the carb. I've encountered multiple saws with each issue, leaking crank seals, leaking various other areas, and carbs that needed the pump side diaphragm replaced. I think most of the time the old needles were still good and it seems to me the two diaphragms are what actually needs changing the most. Also most of the time when I open up a carb they aren't really dirty inside and there is nothing on the screen, but occasionally I will get a pretty dirty one. I put off getting a pressure tester for a long time but now that I'm better at using it I'm glad I got one. Also if you really want a saw to last I like knowing whether it is fully sealed or not, I'd hate to run a saw I like with air leaks and kill it.