May I please get advice on how to repair my Briggs & Stratton (model 33R877) ridemower engine? I'm at my wits end trying to fix this engine.
I'll explain what happened to the engine, and how I tried to repair it. The piston rod broke, killing the engine. The piston rod and the crankshaft needed replacing as a consequence (scouring marks were present where the piston rod attached to it). After cleaning the engine case out, I put the engine back together, but it won't start correctly. Here is what I observe:
1) The electric motor spins the crankshaft.
2) The spark plug does spark.
3) A puff of air blows out of the carburetor, right after sucking air in.
4) The chamber does hold compression, but is released out of the carburetor (I believe this must be the compression release mechanism on the camshaft).
5) The engine does fire when I spray starter fluid into the intake valve, but the exhaust immediately blows out of the intake.
6) The flywheel key is intact, with no obvious damage.
7) The intake rocker arm is spaced to 0.005", and the exhaust rocker arm is 0.006" (the steel pusher rod is on the exhaust valve, aluminum rod on the intake). Spaced the rocket arms with the piston 0.25" down from TDC, both valves closed.
8) The carburetor, SAE 30 oil, gaskets, piston rod, crankshaft, air filter, oil filter, and gasoline are all new.
9) Camshaft compression release seemed OK, no obvious damage to the camshaft either.
10) Flywheel was removed at one point, but put back into place.
I thought I aligned the camshaft and crankshaft (both have dots that one aligns). The only thing I can think of that could be the issue is maybe somehow the camshaft is not aligned with the crankshaft, but how? I thought I aligned these. Is there something that I'm missing? The problem is that ignition takes place with the intake valve open, which to me seems like a timing issue. Either the camshaft/crankshaft are misaligned, or its an electrical timing issue (at least, that's my theory).
Below is a youtube video of that exact same engine model that I'm using. The video is what I followed to put everything back together:
Any advice would be awesome and greatly appreciated, I'm not sure what to do anymore.
