Irish_Jake
Member
Evening all - you may remember me from previous topics here https://forums.yesterdaystractors.com/viewtopic.php?p=9036363&highlight=#9036363 .
I've gotten back to the tractor again, fixed the valve lash clearance, and have begun to assemble the tractor again. However, after putting on the manifold I noticed something strange that fits with earlier observations - I'm getting suction at the exhaust port on the manifold, and pressure at the intake port on the carb. It's consistent in the sense that I only get suction at exhaust and pressure at the intake (the amount of suction/pressure varies as the engine turns over).
I'm turning the engine over with the starter, so unless it's possible for the starter to turn backward either because I replaced the solenoid or wired it wrong, I'm leaning toward the camshaft being the issue. From the tests I was advised to run in previous threads my camshaft timing -looks- correct, my #4 valves are fully closed when the #1 cylinder is at TDC. However, one thread I found here noted that a camshaft 180* out of phase could cause the issue I'm seeing, and although it wasn't totally clear it seems like in that case rather than 90* out of phase I might not see evidence of a problem using that test. I did replace the camshaft gear during my rebuild after shredding it by ignoring one of the 75 tips and running a bolt into it's teeth.
Thoughts and advice? I'm going to double check my wiring but most of my googling along those lines makes me think the starter can't/won't turn backward (and a lot of the threads I found just shifted into old timers waxing poetic). I'm leaning toward the camshaft gear as the culprit, just want input before I lift the tank and tear down the front end again.
I've gotten back to the tractor again, fixed the valve lash clearance, and have begun to assemble the tractor again. However, after putting on the manifold I noticed something strange that fits with earlier observations - I'm getting suction at the exhaust port on the manifold, and pressure at the intake port on the carb. It's consistent in the sense that I only get suction at exhaust and pressure at the intake (the amount of suction/pressure varies as the engine turns over).
I'm turning the engine over with the starter, so unless it's possible for the starter to turn backward either because I replaced the solenoid or wired it wrong, I'm leaning toward the camshaft being the issue. From the tests I was advised to run in previous threads my camshaft timing -looks- correct, my #4 valves are fully closed when the #1 cylinder is at TDC. However, one thread I found here noted that a camshaft 180* out of phase could cause the issue I'm seeing, and although it wasn't totally clear it seems like in that case rather than 90* out of phase I might not see evidence of a problem using that test. I did replace the camshaft gear during my rebuild after shredding it by ignoring one of the 75 tips and running a bolt into it's teeth.
Thoughts and advice? I'm going to double check my wiring but most of my googling along those lines makes me think the starter can't/won't turn backward (and a lot of the threads I found just shifted into old timers waxing poetic). I'm leaning toward the camshaft gear as the culprit, just want input before I lift the tank and tear down the front end again.
