Stemme 914 F2/S1 low power

I note that you had new rubber gaskets installed on your carb bowls.  What kind of gaskets did you have before?

With respect to the torque on the carb bowls: it's been reported that the newer rubber gaskets are thinner than the old gaskets, and that some bowl bolts are just a bit too long with these new gaskets installed, so that, even at the "correct" torque, the seal is not good.  I know some folks have taken a few thousandths off the ends of the bolts, which then allowed the bowls to be sealed properly with the newer gaskets.

https://www.rotax-owner.com/en/912-914-technical-questions/7798-914-stalls-above-idle?start=15

After several months it appears that the low power problem on my 914 may have been resolved.  During static run up this 914 F2/S1 was able to produce 5100 rpm.  Now waiting for balance adjustment on carbs and test flight.

I have been told by the A&P working on my Stemme S-10VT that after lengthy troubleshooting (which included replacement of all induction hoses, gaskets and O rings, rebuild of both carbs, verification of proper operation of TCU and waste gate, swap out of multiple parts) that the height and thicknesses on “some of the replacement parts” on my carbs caused a fuel flow restriction to occur at the threaded needle jet.  It appears that factory replacement parts on both my carbs caused fuel flow to be restricted inside both carburetors and that a .75mm depth variance was discovered between the parts used on my carbs when compared to 2 new ones.  

I am still waiting on Paul Ridgeway, the Stemme repair station IA, to provide clarification and greater detail.

It appears I had a similar problem.  Thanks for your input!

Findings:  Paul Ridgway said he finally was able to resolve why my Stemme 914 F2/S1 Rotax engine produced low power when he discovered that "stacking tolerances were exceeded".  He discovered this by measuring and comparing a factory new carburetor again mine.  In doing this he found that when the older paper float bowl gaskets were replaced with the new rubber float bowl gaskets and properly torqued that a fuel flow restriction was created. Paul said "The paper gaskets didn't crush or compress like the new rubber ones.  The proper torque specified in the Rotax maintenance manual (5.5N-m = 48.67in-lbs)" was used.  I also learned from him that the "newer carb bowls are manufactured 1mm taller than the older ones.

These manufacturing variances caused me the loss of the use of my Stemme for 6 months and over $5,000.00 in maintenance costs.  

Unacceptable!

I do not have a Manifold Pressure gauge installed in 11-028.