Part number question

Ron57

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The engine on my Snapper went bad. The part # is 31P777 0121 B1. I called a B&S dealer and they said the new replacement was 31S977 0005 G1. All the engines i find on line are 1,000-1,400.00. One site i found has a 33S877 0019 G1 for 619.00. It says it replaces 31S977 0005 G1. Same part# that replaces my engine. Can you tell me if 33S877 0019 G1 will work. If not, why? Seems like the electrical connections are the same. Not trying to buy a new mower if possible.
 

StarTech

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Yes will fit. Rated at 19 hp. It is a Promo engine so Briggs is sell it for less than normal price.

BTW the 31S977-0005-G1 is a 17.5hp rated one.
 

Ron57

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Is the pulley and shaft the same? Or do i need to order a new pulley as well?
 

Ron57

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Also, is a promo engine something I should stay clear of?
 

StarTech

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No, they are just the ones they have a big supply of on hand usually. I have sold and install several over the years.
 

Ron57

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Will I need a different pulley? Are the shafts different lengths?
 

Scrubcadet10

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I'm seeing the 31S977-0005-G1 as having a 1"D x 5 5/32" L
Can't find anything on the 31P.
 

slomo

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Thank you! You have been awesome help. I have talked to several live bodies that didnt give much tech info at all. You guys need a tip jar!
I knew we needed a pay section on here for the real pros like ScrubCadet10, StarTech, Bertsmobile1, ILEngine and so on.

slomo
 
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