First time carb pressure test

depends on the seat. Some have a small plastic or rubber seat that a tool extracts and replaces them. Most mower carbs etc., use either a non-replaceable seat or one of those. Autos from pre FI used to have the brass seats that unscrewed like a main jet. Seats are on/off. Main jets depend on mower, application and altitude. A mower that spends its life in Denver CO at 5,200' ASL may have a different main jet than a mower at sea level in Biloxi MS.

How about a brand, model and serial number so we can look in parts to see what is shown?
 
It's a CRAFTSMAN 247.290001, but I'm really trying to learn here, rather than get too deep into this machine. I had 2 of them, and will replace the carb on this one. I appreciate the info on seats, just never saw one of these seats that looked replaceable. This one looks straight brass. I'm familiar with the difference between seats and jets. Thanks for the info.
 
I looked at the parts diagram and a blow up of the major carb parts kit MTD 951-12779. It does not have a seat in it so most likely the seat is not replaceable. I would use something soft like a q-tip to clean it, or if that is too wide, a soft match stick or a small soft brush and blow it out with Berryman's B-12. On a lot of these pieces of equipment, if you maintain it and keep it long enough, you may need a replacement carb so buy one while they are available and keep a spare. Use compressed air to really blow it out afterwards. I always hold it in a towel in case I missed a spring, ball bearing, tube that goes zinging off with compressed air.
 
Thanks. I tried cleaning with plastic brushes from a carb cleaning tool. If I had a skinny enough pencil eraser... I've ordered a carb, and I already have the one I pulled off the other mower, so I've got spare parts. This one works fine, it just leaks at the bowl seal.
 
Try cleaning the seat with a q-tip and some either Flitz Metal Polish or Mother's Mag Wheel Polish. Some flavor of polishing cream. Clean out the polish when done. Carb cleaner or brake juice and compressed air.

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Mark H_NO said:
Thanks. I tried cleaning with plastic brushes from a carb cleaning tool. If I had a skinny enough pencil eraser... I've ordered a carb, and I already have the one I pulled off the other mower, so I've got spare parts. This one works fine, it just leaks at the bowl seal.
Click to expand...
4P90JUA

Large Fuel Bowl O-ring PN 951-12304.
Seat/Fuel Bowl Bolt O-Ring PN 951-12772
No PN Listed for the Fuel Solenoid to Fuel Bowl Bolt O-ring. We are on our own on this one. Not even in the repair kit so just match up one from my o-ring kit.
 
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