HOW DO I SET THE CAMSHAFT TO TIME? I HAVE MODEL 31Q777-112E1. I HAD TO REPLACE THE CONNECTING ROD. THE ENGINE STARTS BUT BACKFIRES FROM THE CARB AND THE EXHAUST GETS HOT, NO POWER EITHER. I TURNED THE CAM 180* AND IT PUFFS FROM THE CARB, WON'T START. I LINE THE MARKS ON THE GEARS.

That sounds like a connecting rod bearing or bearings going bad.

The connecting rods in your engine connect the pistons to the crankshaft. Each connecting rod has bearings at both ends for a snug, smooth fit to the crankshaft. Over time, or due to low oil levels or heat, your connecting rod bearings may wear and allow for play on the crankshaft. This may cause a knocking sound and cause your oil pressure light to activate. These symptoms could also be caused by low oil levels, coolant in your oil, or main bearings, so more diagnosis may be needed. Usually main or rod bearings will cause a knocking noise during acceleration. In time, the connecting rod bearing may seize to the crankshaft, which can break the connecting rod and destroy the engine.

check for a broken compensating spring on the governor to carby linkage

Is there an adjusting screw on the carb? If so turn to the left a little at a time and see if that corrects it.

Here is the procedure:-

1. Remove setscrew from side of cylinder block.



2. Remove oil pipe attaching bolts.



3. Remove oil pump and strainer.

TIMING GEAR COVER

1. Remove timing gear cover to case attaching bolts.



2. Remove timing gear cover and gasket.

CAMSHAFT, CRANKSHAFT, IDLER & INJECTION PUMP GEARS

1. Remove oil slinger and washers from crankshaft snout.
   

Using puller set 49 0839 425C or equivalent, remove crankshaft timing gear, Fig. 3.

1. Position a clean rag between camshaft and idler gears, then remove cam gear lock bolt and washers.



2. Using puller set 49 0839 425C or equivalent, remove cam gear from camshaft, Fig. 3.



3. Remove idler gear to spindle retaining nuts and washers, then remove idler gear and spindle assemblies.



4. Remove injection pump drive gear.



5. Remove timing gear case to cylinder block attaching bolts, then the timing case.

CAMSHAFT

1. Remove tappets from cylinder block.



2. Remove camshaft thrust plate to cylinder block retaining bolts and washers, then pull camshaft from block.

PISTON & CONNECTING ROD

1. Remove connecting rod bearing cap retaining nuts and bolts, then separate bearing cap from connecting rod.



2. Using the wooden handle end of a hammer, push the piston and connecting rod assembly outward until piston rings clear cylinder bore. Remove piston and connecting rod assembly through top of cylinder block.



3. To separate piston from connecting rod, remove piston pin retaining clips, then press pin from piston using a suitable driver.

CRANKSHAFT

1. Remove rear oil seal cap retaining bolts, then the cap and seal.



2. Remove main bearing cap to cylinder block retaining bolts, then the main bearing caps and thrust washers.



3. Lift crankshaft from cylinder block.

I’m happy to assist further over the phone at https://www.6ya.com/expert/uttamjeet_2f3adc18600f8ede

Its time for a rebuild...backfires are caused by a "lean" condition, which means not enough fuel. The oil burning is caused by excessive wear in the cylinder/rings. And the issue with the rod being melted to the crank, well that my friend is lack of lubrication.

Are you referring to connecting rod bearings? If so, I hope you're tooled up and VERY mechanically inclined. If that's the case, you'll want to pull the engine, mount it on an engine stand, remove the bottom components (oil pan, oil pump and any other components that would interfere with a complete and open access to the crankshaft). It is possible to change the rod bearings without removing the top of the engine (intake manifold and carb, valve cover, rocker arm, camshaft, valves, lifters and heads), but I wouldn't recommend you try unless you're a real motorhead. In fact, I wouldn't recommend that you even attempt any of this unless you're very experienced at auto mechanics. Of course, if you're NOT talking about connecting rod bearings, you can disregard everything I've said so far, and elaborate on what you actually want to do.

The loud knock can mean that the connecting rod bearing may be going bad. The engine should be torn apart to see if this is the problem. The lobes on the camshaft should also be checked as well.

Sounds like an over fueling issue, Try resetting the carb to its standard settings, screw both tuning screws right in ant then turn anticlockwise to the following settings H 3/4 of a turn. L 1 full turn. This should set it back to standard. If this doesn't help then it could be a carb diaphram or sticking needle.

The 2.2 is known to "strip" the timing gear. The cam gear is made of a synthetic material. But...you could possibly have an injector bad on #1.

Of the 100+ camshaft replacements that I personly have done on the 425/445 and John Deere Gators I have come across 3 that backfired when completing the replacement.2 were do to bent valves coming in contact with the piston after gear failed and 1 was from a sheared flywheel key.The only other time I had this same injected engine backfire was on a John Deere gator 620i that had a faulty computer and fired @ 90 derees off.Do a compresion check and that will help out alot.