Time for a gasket kit?

[frogy]

Can anyone help me with my Stihl 028 WB it will start right up good but it will only idle for about 15 to 30 seconds before it will take hold and rev up then it will run fine except for irraticle idle. I have change plugs,carb kit,new gas line and filter,air filter,checked for cracks in impulse hose. Thx for any ideas.

 

[NoPaint]

I have found that carburetor kits don't always work. Sometimes after installing the kit I am forced to buy a whole new carburetor and that makes it all work. This has happened to me on a couple different occasions and I have always had luck just replacing the whole carburetor. Also, have you checked for continuous spark? You can get a spark reader from Sears and then just keep pulling the pull cord to see if there is continuous spark or just little bits.

 

[NoPaint]

Also, plugs on these little things go bad if you flood it just once. So have a couple new ones handy and install them fresh RIGHT BEFORE trying to start it up. I had a Vespa engine that would start in the mornings but the next morning only if I installed a new plug. Turns out it would flood at nights and soak the plug. Installing a new plug made it run perfectly. This is one reason I wish small engines had a petcock but also reason to make sure that your diaphragm is not leaking overnight and flooding the cylinder and fouling the plug.

 

[LLigetfa]

I've seen some cases where the carb cleaning didn't actually remove the dirt, just moved it around, only for the dirt to move back to a trouble spot later. Make sure you blow out the journals really well.

I've also seen where the flapper valves will curl either from ethanol or from running the carb dry. I've seen in-tank filters also clog in use, then unclog and clog again. A cracked fuel line can also be the culprit letting in air depending on what position the saw is in. Again, I blame ethanol for cracked fuel lines.

 

[frogy]

Thanks for input. Pulled the muffler and found a scored piston, think thats some of the problem.