Rebuilt top end-had good compression, now I don't????
#43
Completely makes sence.
Does it make sence though- that if I have taken the top end apart twice, and both times I checked it for compression right away it had good compession- Then, later starting the motor with the plug in and all of the sudden loses compression would indicate something not right with the rings. Not much to the two stroke.
But I do agree a leak down test is a good idea
Does it make sence though- that if I have taken the top end apart twice, and both times I checked it for compression right away it had good compession- Then, later starting the motor with the plug in and all of the sudden loses compression would indicate something not right with the rings. Not much to the two stroke.
But I do agree a leak down test is a good idea
#44
a leak down test will tell alot of whats going as far as it wont hold pressure. as far as the rings goes if there in properly and you havent even ran this yet then and you said you put assembly lube reassembling the engine so i'm guessing this isnt the issue. but it's assuming that you have installed all the parts correctly(not saying you didnt or are anyway incableable of doing this right)
#45
Thanks.
Just some more info leading me to think rings. Althought I havn't given you a psi compression reading- it is low enough as to where I can hold my finger over the spark plug hole. So, with that little amount of pressure, if anyone really wanted an exact psi ready, really there isn't much pressure to read. There shouldn't be any leak big enough for me to lose that much pressure, could there? I had the whole motor off and rebuilt- it looked good and everything was sealed back up- halves(resealed), oil seals , new gaskets in place. Motor looked good.
(gaining knowledge)
Thanks
Just some more info leading me to think rings. Althought I havn't given you a psi compression reading- it is low enough as to where I can hold my finger over the spark plug hole. So, with that little amount of pressure, if anyone really wanted an exact psi ready, really there isn't much pressure to read. There shouldn't be any leak big enough for me to lose that much pressure, could there? I had the whole motor off and rebuilt- it looked good and everything was sealed back up- halves(resealed), oil seals , new gaskets in place. Motor looked good.
(gaining knowledge)
Thanks
#47
I rebuilt a golf cart engine about 5 years ago. The compression was 30 PSI before I rebuilt it. At about 50 PSI it was hard to start. At 30 it would not start.
When I tore it down, you could throw a small dog between the piston and bore. The rings came out in pieces and there was NO rubber in the crank seals. I mean none, just the cage!!! This engine still had 30 PSI compression.
The point I'm making is this. I have seen REAL worn out engines and they still have pretty good compression. I have no clue why a fresh engine such as yours has such low compression.
When I tore it down, you could throw a small dog between the piston and bore. The rings came out in pieces and there was NO rubber in the crank seals. I mean none, just the cage!!! This engine still had 30 PSI compression.
The point I'm making is this. I have seen REAL worn out engines and they still have pretty good compression. I have no clue why a fresh engine such as yours has such low compression.
#48
Any advice or anything I should check for when I pull the top end off again to check the rings.
I remember last wkend the rings looked good when I had it off and I rememer seeing lettering on both top sides. I can't remember which ring was on top but I thought I had the right one on top the first time. Namura piston and rings.
When installing, I fit each ring, one end of the ring into its fitting first then tightened the other end around in untill it slid down into the cylider.
Thank you everyone for your help!
I remember last wkend the rings looked good when I had it off and I rememer seeing lettering on both top sides. I can't remember which ring was on top but I thought I had the right one on top the first time. Namura piston and rings.
When installing, I fit each ring, one end of the ring into its fitting first then tightened the other end around in untill it slid down into the cylider.
Thank you everyone for your help!
#50