D-402 Lawn Boy Carburetor - cold start prime not working

[Redpackman]

OK, I've got a D402 model lawn boy. Supposedly it used to be a "commercial model." Recently it had spark and then fuel problems, but now if I use a shot of starting fluid, it runs like a top on the first pull. The problem I have is with the primer pump on the carburetor. According to the LB service manual it says one should be able to see some fuel squirting into the carb when you push the plunger. I can't and w/o the starting fluid it's impossible to start. What have I done thus far:

1. Purchased and installed a new old stock primer plunger with a fresh rubber gasket on it. I thought that would solve the whole issue. It did NOT.

2. Taken the carb off the mower and disassembled the whole thing and cleaned it out as much as I could. Blew carb cleaner into and through every oriface I could find. I even removed the welsh plug and blew through those hidden orifaces and then put in a new welsh plug.

Still no priming going on. I used to be able to prime the mower with this method, but for the last year or two it's stopped working.

Questions for the guys with experience with this carb:
1. Is there a passage way from the primer shaft to the venturi that gets plugged over the years that one cannot access easily? At this point that's all I can figure out.

2. Does this carb have this problem chronically over time?

This is the model carb I have on the mower.

 

[Rivets]

Have you checked the primer line and primer base?

 

[Redpackman]

Have you checked the primer line and primer base?

What is the “primer line?” The carb bowl is full of gas and the bottom end of the primer shaft descends into it. As I said once I give the mower a shot of starter fluid it runs like new. This is not a mower with a primer bulb set up. Rather it’s a pump right on the carb.

 

[Rivets]

Sorry, when you said primer I assumed you miss identified it and you had a 600 series carb. I’ve attached a service manual which should give you an idea how the troubleshoot your carb. I’m thinking the O-ring on the primer may be bad. https://lookup3.toro.com/ttcGateway/acrobat/manuals/lball10.pdf

 

[Redpackman]

The O-ring at the top of the primer is brand new and came with the new shaft and plunger and rubber gasket at the bottom to scoop up the gas. I think I am going to drill out a little hole in the lead shot opening that was used I presume to drill the passage between the primer and the Venturi. That has to have become plugged over the years and there’s no way I can think of to open it up without getting the angle provided by the blocked lead shot passageway.