17hp briggs v-twin misfiring and hard starting

[woo003]

hi, a very confusing one here.
I have a 17hp briggs and Stratton v-twin which is suffering from a number of problems. it is having trouble starting when cold. the engine will crank for ages on choke without going, however when I squirt some fuel in the intake it runs and stays running. I have already bypassed the fuel solenoid and have replaced all fuel lines, filter, spark plugs and governor-throttle spring. I have also tried a replacement carb and it won't run. I am suspecting further problems with the governor? then when I do get it running. it misfires and runs poorly. and it bogs down when throttling up. it also surges at full throttle. I have replaced all intake gaskets and seals and have also tried removing either spark plug boot when running and the problem fixes itself on either side????? any help would be appreciated the engine is model 350 777 vertical shaft. thanks.

 

[Rivets]

Two things come to mind which I don’t see that you have checked. First, the valve’s clearance on both valves on both sides. Second, have you checked to make sure the choke is fully closing. I don’t understand this statement. “have also tried removing either spark plug boot when running and the problem fixes itself on either side????? ”. Please explain and provide the full model, type and code numbers.

 

[TiIngot]

Third place to look - Remove the flywheel and check the key. Timing is off.

I just repaired a Snapper that had multiple issues. Carburetor hooked up wrong, choke was hooked up backwards and fully open not closed when set. Then #1 cylinder pushrods and valve guides broken. Mouse nest over-heated the cylinder head. Brake safety interlock wire broken. Engine shut off when brake released. Valves out of adjustment. The last thing to finally fix it was a sheared key on the flywheel!!

 

[woo003]

thank for your suggestions. I have just checked the flywheel and valves. they are all fine and the flywheel key was also fine. I am going to properly set the valves tomorrow. and I will go from there. I also think it is running a bit lean. so I will drill the jet out a bit as well. if that doesn't fix it I am not sure what will. I will also get the full model type code tomorrow

 

[woodstover]

Have you checked the fuel pump output? Backfiring can be a lean issue.