Motor is a Bf30A LHSA pre-1997
Hey all, I just finished rebuilding my carbs for my motor. It was running very rough before, but after I rebuilt and cleaned the carbs, it started up quickly and sounded beautiful. I am still seeing some concerning signs though, so I am hoping someone can help me understand if any of them are causes for concern.
First of all, I have recently been having problems with telltale strength. Before I rebuilt the carbs, it was a mere dribble, which was much different from what it used to be, the thing used to blast water from its telltale. After I rebuilt the carbs, the telltale blasted strong again like usual. But, three days later, I started the motor, and the telltale was pretty weak again -- not as weak as it was before the rebuild, but noticeably weaker than when I first started it up. I used a carb synchronizer to measure the vacuum in each intake runner, and found that, even though they were in sync, they all had a very weak vacuum. I just replaced the intake manifold gasket and every gasket in the carbs. Why could they all have a weak vacuum, could this weak vacuum be related to the weak telltale, and is it even a problem at all (this motor is very old and has a lot of hours)? I noticed that there was a water passage next to the intake manifold, so I thought maybe a vacuum leak could cause the telltale to weaken. Am I just being over cautious?
Another thing is that the motor was running extremely rough before the carb rebuild. Afterwards, it ran very smoothly. I adjusted the mixture screws and changed the idle speed and got the motor running perfectly. I started it three days later, and it was running slightly rough again. What could cause this quick deterioration? I noticed that the air coming out of the exhaust felt sputtery. Is it supposed to feel that way? The motor seemed to sound like it was missing every now and again, but I'm not sure (I'm no expert here).
I haven't done a valve clearance adjustment yet, could that make a big difference?
So, are these things causes of concerns, and if so, what are the possible causes/solutions?
Totally beside the point, but the fuel pump hasn't been replaced since the motor was bought (20 odd years ago). Is that something I should consider replacing?
Hey all, I just finished rebuilding my carbs for my motor. It was running very rough before, but after I rebuilt and cleaned the carbs, it started up quickly and sounded beautiful. I am still seeing some concerning signs though, so I am hoping someone can help me understand if any of them are causes for concern.
First of all, I have recently been having problems with telltale strength. Before I rebuilt the carbs, it was a mere dribble, which was much different from what it used to be, the thing used to blast water from its telltale. After I rebuilt the carbs, the telltale blasted strong again like usual. But, three days later, I started the motor, and the telltale was pretty weak again -- not as weak as it was before the rebuild, but noticeably weaker than when I first started it up. I used a carb synchronizer to measure the vacuum in each intake runner, and found that, even though they were in sync, they all had a very weak vacuum. I just replaced the intake manifold gasket and every gasket in the carbs. Why could they all have a weak vacuum, could this weak vacuum be related to the weak telltale, and is it even a problem at all (this motor is very old and has a lot of hours)? I noticed that there was a water passage next to the intake manifold, so I thought maybe a vacuum leak could cause the telltale to weaken. Am I just being over cautious?
Another thing is that the motor was running extremely rough before the carb rebuild. Afterwards, it ran very smoothly. I adjusted the mixture screws and changed the idle speed and got the motor running perfectly. I started it three days later, and it was running slightly rough again. What could cause this quick deterioration? I noticed that the air coming out of the exhaust felt sputtery. Is it supposed to feel that way? The motor seemed to sound like it was missing every now and again, but I'm not sure (I'm no expert here).
I haven't done a valve clearance adjustment yet, could that make a big difference?
So, are these things causes of concerns, and if so, what are the possible causes/solutions?
Totally beside the point, but the fuel pump hasn't been replaced since the motor was bought (20 odd years ago). Is that something I should consider replacing?