3300 low power ?

HiHo,

I suspect that my Jabiru 3300 motor is underpowered because it does not get up to the required RPM when stationary on the ground. I reach a maximum of 2100 rpm.

It has no measurable effect when using different propellers from the same manufacturer and identical length (Helix). I have tried propellers with 10, 11 and 12 degrees pitch and always the same effect, never more than 2200 rpm when standing on the ground.

Today I removed the air filter and the supply air now comes directly into the Bing carburetor, again without significant effect.
More RPM does not come from this.
It also doesn't matter if you turn on the additional electric fuel pump or not.

What else could it be and in what order do I best proceed to isolate the problem?
Too little fuel, possibly the wrong jetting, no or too little compression?

Does anyone have a suggestion for me please ?

Thank you and happy new year to you all.

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Permalink Reply by Warren B Peck on March 12, 2022 at 5:16pm

I scanned thru the voluminous suggestions and didn't see this one. When you push your throttle to wide open, is there at least an 1/8th of an inch of throttle cable left when the carb is at WOT? If not, maybe you're not actually at WOT? js.

Permalink Reply by Jerry Griego on May 8, 2022 at 8:11pm

I fought this problem a few years back, I could take the carb apart with my eyes closed. I broke down and bought a new carb. and used the jetting that was recommended from Bing. All my problems went away. One more thing check that there is nothing inside the muffler restricting exhaust from full flow.  I also found this problem with a scope camera. I found the obstruction before I bought the Carb.

Permalink Reply by Dan Dempsey on May 23, 2022 at 1:51pm

I just read through this long thread.  I had the opposite problem after installing the Gen 4 3300.  My RPM were going to near 3500 as indicated by my Tach.  This wound up being a problem with the Tach settings.  Once fixed it showed 2850 static/full power.  It occurs to me you could have the same problem, Tach reading wrong because not set up correctly.

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