Engine swap, good or bad?

[tom4018]

20 hp Briggs twin cylinder is trashed but found some new 17.5 hp Briggs single cylinder for a good price. Will it pull a 46" mower deck ok? Looks like it will fit but will have to modify the hood for exhaust. Just wondering if I will be happy power wise. Trying not to have to go in debt to buy a mower.

 

[MikeInEburg]

If it physically fits, it'll work fine. Obviously, you won't have quite the power, so you may need to mow a bit slower. Most mowers are really overpowered anyway...
Mike

 

[alchemysa]

It will probably do the job, but I think you'll find a single cylinder a big disappointment after having a twin.

 

[Wis Bang]

How bad is the 20? You can get a 'shortblock', basically a new engine minus all the externals & just move over your ignition, induction and tins. That's alot cheaper than buying a whole new engine. A few years ago I shortblocked my friend's Simplicity w/ 11hp B & S for $300 while they wanted close to $700.00 for a complete, ready to bolt on new engine.

OTOH 3 hp isn't all that much but you will notice a difference in torque VRS a twin, if youare the patient type you should be fine. My buddies 11hp w/ bagger was the same tractor as my sisters 8hp w/ no bagger.

 

[FlaDon]

Even if you have a single and a twin rated at the same HP, the twin will perform better under load. Torque for the twin will be more even over the single per revolution of the engine.