At Fixya.com, our trusted experts are meticulously vetted and possess extensive experience in their respective fields. Backed by a community of knowledgeable professionals, our platform ensures that the solutions provided are thoroughly researched and validated.
What is Wrong With a Stihl FS90R Trimmer When The Primer Bulb Won't Fully Fill After Priming?
When I Prime it, some fuel comes into the bulb but it will not fill. When I prime it with the gas tank cap off, the bulb fills all the way up with gas.
Re: What is Wrong With a Stihl FS90R Trimmer When The...
1) check valves inside the primer plate is sticking
2) fuel pump diaphragm is varnished and flaps are sticking to the body of the carb
3) the cost of parts and time spent are more than a new carb
4) new carbs are updated versions and have updated ethanol resistant components
** suggest a new carb, it will solve several performance issues
- If you need clarification, ask it in the comment box above.
- Better answers use proper spelling and grammar.
- Provide details, support with references or personal experience.
Tell us some more! Your answer needs to include more details to help people.You can't post answers that contain an email address.Please enter a valid email address.The email address entered is already associated to an account.Login to postPlease use English characters only.
Tip: The max point reward for answering a question is 15.
a primer bulb should not actually fill, that said, if it is not priming your carb then there might be a tiny crack or pin hole that is letting air in as you try to prime, order and change the primer bulb.
need new carb... Primer plate is bad. They will run without it working. Your idle problem is separate from this issue. Fresh fuel/oil mix might help. Some Stihl carbs we just replace because they are cheaper than trying to rebuild...
Sounds like you have an air leak. Either in the primer bulb is split or punctured, hole or leaking fuel line or primer bulb base, and is sucking air instead of fuel.
If you have a leak the bulb will not prime. Over time the either the rubber on the primer bulb gets a pin hole in it requiring bulb replacement or one of the fuel lines cracks and introduces air into the lines. Unless the system is completely sealed the primer bulb will not work. Make sure all of the connections on the fuel lines are tight and correct the system leaks.
I would recheck the carburetor to make sure you put the diaphragms next to the carburetor and not the gaskets. Please if it is not priming you may have the fuel lines hooked up wrong. Also check the fuel cap to make sure the vent assembly is there. If the tank is not venting, the tank will get a vacuum in it not allowing fuel to flow. HTH Good Day.
when you prime the bulb it sucks gas from the tank with the small tube, any excess gassed pumped will be fed back to the carb via the big tube leading to the tank. If you prime it and the bulb stays pushed down, then you have a clog or kink. To fix , pull the small tube out of the tank through the fill hole. Pull off the filter on the end and put the tube back in the tank. If it primes, your fuel filter was clogged. If it still wont prime check the hose going to the carb and make sure isnt clogged or kinked.(take of carb and blow in it). If that doesnt fix it take off the bulb from the carb with two screws. The bulb assembly will come off too(rectange metal thing) Take off the two black gaskets, be carefull with them. Take off hoses from carb and bulb asembly. Blow carb cleaner in all holes and over surface. Put back together. If the carb wont prime and the bulb isnt staying depressed. then you might have a bad bulb or carb gaskets. Make sure hoses are not cracked, cloged, or pinched.
it sounds like the filter on the fule line is cloged try to remove the filter and then try to prime the trimmer. it it does you need to replace the filter. just about any filter that will fit will do.
×