5hp Briggs & Stratton, idles great, but won't throttle up.

My money is on a partial blockage of the main jet or the passageway to it. You're having to force it to run through the idle jet by fully choking the incoming air. There's not enough gas coming in with the choke open to allow it to run.

I'm thiniking total carb disassembly, carb cleaner and an air compressor combined with a ton of patience will take care of the issue.

http://www.jackssmallengines.com/Jacks-Parts-Lookup/Manufacturer/briggs-stratton/70798 Try this link it should help. You can click on B&S and enter your model and choose diagram you like.

I’m happy to assist further over the phone at https://www.6ya.com/expert/layne_0fccff498c319c32

Does the engine want to bog down when you move the throttle? Or does it do absolutely nothing?
If it bogs down when you try the throttle, It could be:
water in the gas
bad or distorted diaphragm (if no float)
stuck needle valve
stuck float

I’m happy to help further over the phone at https://www.6ya.com/expert/karl_14766549451f8563

there should be a little screw to help adjust your idle try that..counterclockwise to add more idle, clockwise to slow idle..

replace air filter, check throttle linkage position, take to a pro shop and have governer adjustment checked

Hi sheets calvi...
I have found a webpage that you can download a free user manual for your Troybilt 258...
Go to the following webpage download and print out (so you have a hard copy).
Please take time to rate me

http://lawnandgarden.manualsonline.com/manuals/mfg/troybilt/258.html

Hi, you can get one through any Briggs and Stratton dealer. Regards Phil.

It appears that you have a slight mis-adjustment in the idle speed and idle mixture. To adjust setup, start with at least a half tank of fuel, and have engine at operating temperature (That is warm but not overly Hot). The Briggs & Stratton Website manuals section should show the locations of the adjusting screws if you are not sure of them.
To adjust idle speed set Throttle control to minimum and adjust screw on throttle butterfly to maintain a good idle speed. To adjust idle mixture, screw in idle mixture screw (Lean) until motor falters and then screw out (Rich) until it falters again. Correct setting is the halfway point of these two positions. You may have to re-adjust idle speed again and also the mixture to get best running.
If you are not comfortable doing this, take it to a B & S dealer.

drain the g/box and see what comes out.if its got water and oil mixed,Id try for a claim.being aircooled motors,there should be no problems for long time,no impellors,just a B

Try cleaning the air filter, and check fuel tank for any debris.
Replace fuel filter if there is, and give the fueltank a good cleanout.
Use fresh fuel to refill.