fs90r primer problems.

[alabamatriker]

ok working on my dad's old stihl fs90r. The primer has been cracked since he got it. He just pulled plug and primed with a little mix. He did this for 6 years. He says that it got to where it would only run at idle. I got it yesterday. Now says wont start. I put new primer on without pulling carb. It pumped up fine. installed new plug. It would fire right up and idle good. It would die when throttled up. Pulled carb and cleaned it. very careful to put diaphrams and gaskets back in right order. Now it wont prime or idle but runs good wot. Sounds like the primer is sucking air when pumped. the top diaphram was stuck on one corner so did not pull it all way off. If this is split will it cause this problem?

 

[blades]

Possible, a pin hole can cause problems. did you check the impulse and fuel lines

 

[rngrchad]

first thing id check is the primer bulb pickup line. Make sure its actually long enough to make it into the fuel in the tank. Recently had an echo 1100gt and the primer pickup line only went into the tank 1/4" so it wouldn't prime......