Sometime the boost fuel pump on my TB20 acts a little bit ‘lazy’ at startup, taking a second or two to get to full speed, as if it is somehow clogged or something prevents it from starting.
It happened at least one time that it didn’t start at all, after a long period of inactivity.
Is there any known issue with this that I should consider first, such a cleaning or overhaul, before starting to look for a brand new replacement?
Could be something that draw current at the same time, that lowers battery voltage for some seconds until it stops. Did you have a look at battery voltage when you switched it on?
There is nothing else that draws current at that time, I only start the electrical pump before engine start.
However, I suspect the battery has some health issues, as it rapidly goes below 11.5V if for exame I leave the avionics bus on for a few minutes, with no alternator.
If the pump noise does correlate with battery voltage (sound change when voltage drops), it is probably the case, otherwise it could be more mechanical issue.
