TIPSYNIPPER
Active Member
Rotec TBI going too lean due to high temperatures.
Yesterday I found that after a long taxi out with the carb' heat on (intentionally, I was on very soft wet grass with OAT about 5 deg C, perfect carb' ice conditions) when I came to do power checks at 1700rpm the engine was running rough with a 250rpm drop on each ign' system (dual Pmags). The engine was running seriously lean, so I taxied back to the hanger, de-cowled and had a good look, nothing to see. The carb' temp' (I have a temp' sensor in the fuel gallery in the Rotec TBI) was at 25+DegC. I then ran the engine without cowls and the fault eventually disappeared.
Today I kept the carb' heat off, power checks normal, had a good fly. On return I kept the carb' heat on during taxi and found I could replicate the same fault (very lean mixture) once the carb' temp' reached 25degC+.
It would seem that for a reason yet to be determined the Rotec has a problem with high body temp's. (the pressure regulator is force air cooled so I suspect the reg' temp' was much lower).
This bit of info' may help some of you having issues with mixture.
I will email Rotec and run it by them and report back.
Happy Chrimbo All.
Neil
Yesterday I found that after a long taxi out with the carb' heat on (intentionally, I was on very soft wet grass with OAT about 5 deg C, perfect carb' ice conditions) when I came to do power checks at 1700rpm the engine was running rough with a 250rpm drop on each ign' system (dual Pmags). The engine was running seriously lean, so I taxied back to the hanger, de-cowled and had a good look, nothing to see. The carb' temp' (I have a temp' sensor in the fuel gallery in the Rotec TBI) was at 25+DegC. I then ran the engine without cowls and the fault eventually disappeared.
Today I kept the carb' heat off, power checks normal, had a good fly. On return I kept the carb' heat on during taxi and found I could replicate the same fault (very lean mixture) once the carb' temp' reached 25degC+.
It would seem that for a reason yet to be determined the Rotec has a problem with high body temp's. (the pressure regulator is force air cooled so I suspect the reg' temp' was much lower).
This bit of info' may help some of you having issues with mixture.
I will email Rotec and run it by them and report back.
Happy Chrimbo All.
Neil