B&S Intek 20hp mounting footprint compatibility

scottmarsc

Forum Newbie
Joined
Aug 7, 2017
Threads
3
Messages
9
My Poulan Pro PP20VA46 B&S 20hp engine has died (40N877-0004-G1) and I'm looking to replace it with a B&S 20hp engine (40N777-0031-B5) . Can I presume they have the same mounting footprint so the engine holes will line up with the frame holes?
 

ILENGINE

Lawn Royalty
Joined
May 6, 2010
Threads
44
Messages
10,776
My Poulan Pro PP20VA46 B&S 20hp engine has died (40N877-0004-G1) and I'm looking to replace it with a B&S 20hp engine (40N777-0031-B5) . Can I presume they have the same mounting footprint so the engine holes will line up with the frame holes?
Mounting pattern is standard across engines of the same brand as well as other brands.. So a Kohler, Briggs, Kawasaki, Honda will have the same mounting pattern.
 

Forest#2

Well-Known Member
Joined
Apr 17, 2022
Threads
0
Messages
463
I've noticed when Poulan's name is involved you cannot assume anything.
 

scottmarsc

Forum Newbie
Joined
Aug 7, 2017
Threads
3
Messages
9
Thanks all for the input! Since there are only 4- threaded mounting holes on the bottom of the block I will assume it is standard across the B&S 40N models.
 

ILENGINE

Lawn Royalty
Joined
May 6, 2010
Threads
44
Messages
10,776
Thanks all for the input! Since there are only 4- threaded mounting holes on the bottom of the block I will assume it is standard across the B&S 40N models.
Standard from at least the 28xxxx series up to 46xxxxx series. The 13xxxxx-25xxxxx and 54xxxxx-61xxxx may have the same footprint also.
 

Forest#2

Well-Known Member
Joined
Apr 17, 2022
Threads
0
Messages
463
Not hard to drill mounting hole.
I take cardboard and make a template when the old motor is off the tractor, (if no fit) trace the center hole onto the cardboard. cut out the center per the trace and then center it on the donor motor and mark the donor's mounting holes onto the cardboard. Take it too the tractor and drill.
What I really watch out for is the shaft sizes and lengths of the donor motor vs the other, especially if pulleys from the old motor cannot be used onto the donor motor.
 

Tiger Small Engine

Lawn Addict
Joined
Dec 7, 2022
Threads
2
Messages
1,134
Not hard to drill mounting hole.
I take cardboard and make a template when the old motor is off the tractor, (if no fit) trace the center hole onto the cardboard. cut out the center per the trace and then center it on the donor motor and mark the donor's mounting holes onto the cardboard. Take it too the tractor and drill.
What I really watch out for is the shaft sizes and lengths of the donor motor vs the other, especially if pulleys from the old motor cannot be used onto the donor motor.
Also, how does the exhaust fit, is the wiring a direct plug and play, throttle cable hook ups the same?
 

Forest#2

Well-Known Member
Joined
Apr 17, 2022
Threads
0
Messages
463
Also, how does the exhaust fit, is the wiring a direct plug and play, throttle cable hook ups the same?

engine swaps even small lawn tractor engines for example can be time consuming. Murphy is waiting and watching close for you during such.
If electric PTO needed, will the donor engine have correct charging system.

If you don't think about such at first, well you know the time/sweat /cost that can be involved and may have to throw in the towel later instead of sooner.
 

scottmarsc

Forum Newbie
Joined
Aug 7, 2017
Threads
3
Messages
9
Thanks for all the guidance & input! Swap was made, mounting holes lined up perfectly except the new motor mounting holes were not tapped. Ace Hardware to the rescue with 4 new mounting bolts/nuts. All connections were compatible, and it started right up! Replaced the deck and main drive belts since they were badly worn, and oil soaked. Have posted a new thread concerning the drive operation- once forward pedal is pushed, the tractor will not stop until the brake is depressed. Same with reverse. Drive belt need tension adjustment?
 

Forest#2

Well-Known Member
Joined
Apr 17, 2022
Threads
0
Messages
463
link to new thread???
 
Top