Hi all
I purchased a Vermeer stump grinder with a Honda GX620 on it. I knew the motor had problems and would like some help and direction before I tear it down.
The motor had thrown and bent a push rod 3 years earlier and the thing was abandoned and left in the rain for a period of time.
Water in oil so I dumped that, fresh fuel, plugs, filters and gave it a compression test.
120psi pot 2
60psi pot 1
First question does this have a decomp on pot 1
Anyhow thought a run would help so fired her up. 2 minutes or so and all good, then pang pang pang pang pang. Shut her down, sounded like a valve seat or something high up. Pulled rocker covers (po had replaced push rod) and found the collet thing that sits on top of the exhaust valve is loose in the head. Undid rocker arm, replaced collet, set to .15 and .2 on both pots. Was sure I had found noise but no, fired up and same valve noise on no1.
Pulled no1 valve train, one guide is showing a bit of wear and a slight bend and the guide has been a bit butchered.
Pulled no2 valve train and all good.
With rocker gear and spark plugs out the motor turns over but if you approach tdc on no1 it has a tight spot just before it. Could this be the decomp if it has one?
The pang noise also sounds like a valve but I’m guessing it’s every revolution like a 2 stroke so probably not the exhaust or intake valve.
Wondering if this tight spot is the cause of the pang noise.
I purchased a Vermeer stump grinder with a Honda GX620 on it. I knew the motor had problems and would like some help and direction before I tear it down.
The motor had thrown and bent a push rod 3 years earlier and the thing was abandoned and left in the rain for a period of time.
Water in oil so I dumped that, fresh fuel, plugs, filters and gave it a compression test.
120psi pot 2
60psi pot 1
First question does this have a decomp on pot 1
Anyhow thought a run would help so fired her up. 2 minutes or so and all good, then pang pang pang pang pang. Shut her down, sounded like a valve seat or something high up. Pulled rocker covers (po had replaced push rod) and found the collet thing that sits on top of the exhaust valve is loose in the head. Undid rocker arm, replaced collet, set to .15 and .2 on both pots. Was sure I had found noise but no, fired up and same valve noise on no1.
Pulled no1 valve train, one guide is showing a bit of wear and a slight bend and the guide has been a bit butchered.
Pulled no2 valve train and all good.
With rocker gear and spark plugs out the motor turns over but if you approach tdc on no1 it has a tight spot just before it. Could this be the decomp if it has one?
The pang noise also sounds like a valve but I’m guessing it’s every revolution like a 2 stroke so probably not the exhaust or intake valve.
Wondering if this tight spot is the cause of the pang noise.