GCarr Posted September 22, 2012 Report Posted September 22, 2012 My Grob 109B (G2500) runs up fine during a static test and attains 2700 rpm without any problem. On take off when the rpm reaches 3000 and above, a continiuous intermittent engine cut out occurs. If one reduces the rpm it runs fine. I have tested the left and right magentos individually at 3000 rpm but the problem still occurred irrespective of either magneto.I have had a compression test and a blow-by test which was satisfactory. I have checked the mechanical and electrical fuel pumps for flow but did not find any problems.The oil pressure and temperature and within the normal limits. The fuel is avgas and does not contain water or impurities.I have now removed the carbuettors to check the jets, float level etc. though I am need too sure if the carburettors are contributing the the cut out.Has anyone experienced something similiar as its quite a difficult problem to solve as the rpm is only attained while taking off or flying.Gareth Carrgjcarr@gmail.com Quote
GCarr Posted September 22, 2012 Author Report Posted September 22, 2012 My Grob 109B (G2500) runs up fine during a static test and attains 2700 rpm without any problem. On take off when the rpm reaches 3000 and above, a continiuous intermittent engine cut out occurs. If one reduces the rpm it runs fine. I have tested the left and right magentos individually at 3000 rpm but the problem still occurred irrespective of either magneto.I have had a compression test and a blow-by test which was satisfactory. I have checked the mechanical and electrical fuel pumps for flow but did not find any problems.The oil pressure and temperature and within the normal limits. The fuel is avgas and does not contain water or impurities.I have now removed the carbuettors to check the jets, float level etc. though I am need too sure if the carburettors are contributing the the cut out.Has anyone experienced something similiar as its quite a difficult problem to solve as the rpm is only attained while taking off or flying.Gareth Carrgjcarr@gmail.com Quote
kestrel539 Posted September 22, 2012 Report Posted September 22, 2012 My Grob 109B (G2500) runs up fine during a static test and attains 2700 rpm without any problem. On take off when the rpm reaches 3000 and above, a continiuous intermittent engine cut out occurs. If one reduces the rpm it runs fine. I have tested the left and right magentos individually at 3000 rpm but the problem still occurred irrespective of either magneto.I have had a compression test and a blow-by test which was satisfactory. I have checked the mechanical and electrical fuel pumps for flow but did not find any problems.The oil pressure and temperature and within the normal limits. The fuel is avgas and does not contain water or impurities.I have now removed the carbuettors to check the jets, float level etc. though I am need too sure if the carburettors are contributing the the cut out.Has anyone experienced something similiar as its quite a difficult problem to solve as the rpm is only attained while taking off or flying.Gareth Carrgjcarr@gmail.comSounds similar to a problem I had, & you are probably on the right track by checking the carbs, but it may be worth checking the turbulators in the intake manifold.They should NOT be free to rotate, if they do, glue them in place. Have you also checked the fuel flow you get?One final thought...timing?CheersIan KPS, my problem was cleared by getting the carbs re-set to factory settings, and getting the turbulators sorted. Quote
kestrel539 Posted September 22, 2012 Report Posted September 22, 2012 My Grob 109B (G2500) runs up fine during a static test and attains 2700 rpm without any problem. On take off when the rpm reaches 3000 and above, a continiuous intermittent engine cut out occurs. If one reduces the rpm it runs fine. I have tested the left and right magentos individually at 3000 rpm but the problem still occurred irrespective of either magneto.I have had a compression test and a blow-by test which was satisfactory. I have checked the mechanical and electrical fuel pumps for flow but did not find any problems.The oil pressure and temperature and within the normal limits. The fuel is avgas and does not contain water or impurities.I have now removed the carbuettors to check the jets, float level etc. though I am need too sure if the carburettors are contributing the the cut out.Has anyone experienced something similiar as its quite a difficult problem to solve as the rpm is only attained while taking off or flying.Gareth Carrgjcarr@gmail.com Quote
GCarr Posted September 25, 2012 Author Report Posted September 25, 2012 We discovered that the floats were set at 20mm instead of 18mm and one of the floats was upside down. This caused fuel starvation at high power/demand. I have just taken transfer of this aircraft and know that the previous owner messed around with the carbs. Quote
GCarr Posted September 25, 2012 Author Report Posted September 25, 2012 We discovered that the floats were set at 20mm instead of 18mm and one of the floats was upside down. This caused fuel starvation at high power/demand. I have just taken transfer of this aircraft and know that the previous owner messed around with the carbs. Quote
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