sears weed wacker wont start [Archive] - HobbyTalk

: sears weed wacker wont start

09-04-2005, 05:00 PM

I am new to this forum so I hope you all can help.
sears 21 cc , model 358.798560
unit was running crappy had to keep the throttle on or it would stall. I suspect it was bad gas from last year.
I changed the gas and now it wont start, just a little burp.
I took off the carb and cleaned it, twice. Now it doesnt even burp.
I checked for spark and used a new plug, still nothing. Compression feels like it always did. I tried starting fluid even gas directly in the cylinder and zip.

Any thoughts for repairing or is it time to get another one. I think it is about 9 years old.


09-04-2005, 08:09 PM
did you take the mixture screws out? and shoot em out from there? you may could try to adjust em, 1 to 1.5 turns out from going all the way in snug, it may have the limiter caps still on, but you can pop em off. too rich can dround the plug out making it wet. gas and ether doesn't make it fire? also go through other things, spark arrestor and exhaust port for clogging, and gas lines for cracks, etc.

09-04-2005, 08:24 PM
Ya can you believe it gas and ether wont crank it up. I am starting to get a burp every now and then. I need to pop the limiter cap off so I dont need to take it all apart everytime I want to change the needle setting. I moved the screw out 3 turns and the plug gets real wet. I gave up for tonight. I will try changing the screw setting since I started to get a burp. Sometimes I see air bubbles in the line when priming??? They do go away. I wonder about the black diaphram, could it be stuck open/closed? because it is not moving enough?? I pulled the carb apart and there is gas behind the diaphram. I did not replace any of the gaskets(did not have them when I started this and today is Sunday plus the darn Holiday).

Well I hope my shoulder holds out after all of the pulling, not to mention the blister on my finger..............

09-04-2005, 08:35 PM
well, you can get a gasket kit, and all. now if the plug gets wet, they then become hard as hell to start, try to dry it off.... remember 1 to 1.5 turns out, from screwing it all the way in snug, not wrenched. the diapragm is there to pump the gas... sounds like its working, though they can get stiff and won't, also about the lines, just inspect em for cracks.

09-04-2005, 10:37 PM
good trick for wet plugs..hold it over the gas burner in the kitchen stove(just make sure wifey is gone). That will dry it out & burn off the excess gas. If you have electric stove your propane torch will do the same. if you dont have a propane torch, try kitchen matches..This also pre-heats the plug & makes it easier to start. Good Luck!!

09-19-2005, 08:25 PM
I'm having a problem with the weedwacker too but my problem is that I can't get the gas from the contained to the engine. The primer pumps but even with a new gas filter nothing get to the engine. It will operate for a short time if I spray starting fluid in the carb. but that's it. Could it be that one of the lines to the engine or from the gas container has a leak?? Any suggestions??

09-19-2005, 09:44 PM
Most likely the carb needs to be disassembled and cleaned.

09-19-2005, 10:10 PM
check the gas lines very good for cracks, but if the primer is getting gas, may or may not have a crack/leak. just go over the lines good. then yeah carb cleaning next thing to do

09-20-2005, 04:39 AM
Thanks... I'll give it a try but what I don't understand is that when I press the primer bulb it doesn't pull gas. Gas is not getting from the container to the engine no matter how many times I press the primer bulb. I'll see what happens this afternoon. Thanks again.

09-20-2005, 03:01 PM
did you take the fuel lines off? they may have been switched around

09-24-2005, 08:26 PM
Check out what I did in my post "Craftsman Blower no start" These folks helped me out greatly! Turned out it was the diapraghm was blown... I got it and the gasket for ~ $2 from a local shop...

HTH, Eric