Briggs & Stratton and 13R232-0001-F1 Engine,Black,14.5 x 12 x 13.5 inches

Q: Does it have mounting holes on the side to mount a hydraulic oil pump

Yes, it does. I used this engine as a direct replacement for an old 5 horsepower Briggs & Stratton engine on my log splitter. Everything lined up perfectly.

Q: what is the shaft length?

Crank Length 2-7/16, Crank Diameter 3/4, Crank Height (in.) 4.17.

Q: Need a replacement engine for b&s 5 hp model 135232, type 1161 e1, code 990816yb. what b&s engine will replace it.

I ordered a briggs for my tiller. What I got was a Briggs from china. Fuel tank was dinged and paid was chipping away right out the box. I sent it back the same day. It was exactly what you'd get at harbor freight only black with Briggs logo on it. I believe Briggs has a cheap china line and a better us line. Make sure you get the us line. Make sure its plastic fuel tank so the tank doesn't rust over winter. Or do like I did and buy a Honda. There is a Co. That sells open box new tested motors. My honda is a bit smaller then the briggs I was going to get but has all the power to run my tiller and one pull start. If you do get a honda or Briggs. Make sure it has the throttle for rpm adjustment unless you dont need that. As far as what particular models you need. I cant help you.

Q: What is the distance from One Bolt Mounting hole to another?

The mounting plate seems to be standardized. My front and rear mounts are each 3" apart with 6" between front to rear. You can download the manual online. Briggs & Stratton manual also lists other key dimensions which include: crank length (2-7/16"), crank diameter (3/4"), and crank height (4.17"). Match the crankshaft height: key way, tapered or threaded. Depending on your application verify the engine will fit in the available space, height/width and that the fuel location will be accessible.