[NSRCA-discussion] Thoughts about lack of power of my DA150??

[PPandelaers]

Hi guys,

 

I'm wondering if you have opinions on my below assumptions. It's a mail I
have sent to DA, but no answer as of yet. 

 

Could I be right, should I rather lengthen or shorten my exhaust system?

 

Thanks

 

Patrick

 

 

 ============================================================

I'm running a DA150 on MTW, short cans TD75K, Mejzlik 28.5x12

 

 

Started running-in the engine a couple of months ago. From day 1, I got 5600
RPM.

Now, 50 liter gas down, no change at all in RPM :-(  I get exactly the same
RPM on a 32x10 2-blade.

I'm experiencing great difficulty in adjusting the engine. I don't seem to
be able to get full power, particularly not in the air. I get the feeling I
don't even get the 5600 in the air.

Tried about anything you can imagine, with adjusting needles, soldering a
little tune on the diaphragm cap, measuring pressure where it should be
done.

 

 

Let's forget about air behaviour, I would expect significantly higher RPM,
even on the ground. Motor is not sagging when I keep it running full
throttle, I baffled the engine, cooling is adequate.

 

Here's what I think is going wrong, I would really like to get your opinion
on it.

At 5600 RPM, I think I get some refection of the exhaust system exactly
during the intake timing.  If this is so, I just can't get enough mixture
inside the cylinder. 

At low RPM, it's always running rich, if I want to improve that, I have to
tweak the "L" as low a 3/8 (instead of the 5/8) . The high needle is not
sensitive at all, it's like it doesn't matter where you put it. With the
low, at 3/8, starting a cold engine takes several restarts.

 

The distance of piston to the first wall in exhaust systems is about 630mm

 

*	Could I be right? 
*	How much would I have to lengthen or shorten the exhaust tubing?
*	Secondary questions:

*	How many degrees is the intake open, 
*	When does the intake open: How many degrees from exhaust opening
(piston moving down) till intake port opens?

*	What RPM should I expect on the Mejzlik 28.5x12. 

 

 

 

Your advise would be highly appreciated!!!

 

Patrick

 

 

 

 

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