low speed on max throttle

I have an old 3 hp toro 92908, self propelled, auto choke, fwd, b&s eng #1842-02. I have kept it running over the years with routine maintainance only, no major repairs. I keep the gas tank empty in the winter and fuel it in the spring. A year ago I replaced diaphragm with oe B&s, and it has run perfectly since. This spring, it started on the first pull after winter, but has a low, even idle speed at max throttle. The choke plate is closed, but the idle becomes full speed when I manually open the plate to full vertical position while the engine is cold, not hot, on a fresh start. I let it get hot with the choke plate held open, and once hot, I was able to mow at full speed, and stop and start with no problem. I get no surges or roughness. There is no reason to think I have accidentally turned the idle speed or mixtures screws while in storage, and I find it hard to believe the NEW diaphragm has failed. Any suggestions to solve this problem appreciated

The Toro model number is 16320, with all the other info I provided being accurate regarding the B&S engine. Sorry I gave the wrong mower model number. Is that why I have received no reply?

there are 5 or 6 numbers in front of the 1842 in the model number. Without it we don't know if you have a 8,9 or 13 ci engine.

BRIGGS & STRATTON CARBURETOR ASSEMBLY MODEL 92908-1842-02 FOR 21" SELF PROPELLED MODEL 16320.

I believe the numbers you are looking for are , 92908, as I stated in my original post. I do not understand how that will change the suggestions for dealing with carb/fuel delivery, as I also stated this has the auto choke. Hope you can help.

You actually said in your original post you had a 3 hp toro 92908, and I didn't connect it with the rest of your model number later in the post. Anyway, from your description it sounds like the vacuum system isn't opening the choke on startup. Did you do the choke preload setup when you installed the diaphragm last year. Acts like either the diaphragm has failed, or you have lost the preload.

Try loosening the carb screws, holding the choke past fuel open, meaning turn it past straight up,and while holding it tighten the screws back down.

There is a problem when you double post.
Some read the forum on theri computer as a web page, others get it as a series of emails thus if what is on one post is different to the other the people who use emails get very confussed.
On one of them ( you choose ) post, in big letters
"This thread is closed please see ( name of other thread ) "

t
Then we will quite literally al be on the one page and no one will get confused or upset because things seem to be contradictory.