618 help please

[Aerosan]

Hi all

I have a problem on my koala. I have 618 in there and she is going well just one small problem. If im at say 90% power +/- 5200 and I open the throttle fully she takes a dip in rpm before going up? Maybe 200/300 rpm so it is rather big the it doesnt affect the plane but it defenetly there. Does anyone have any ideas?

Im new to this so anyadvice will help.
Thanx
Aerosan

[Aviation Engines]

Sounds like it's running rich in the top end.

What is the total operating time on the engine?
When last were the needles and needle jets changed? These should be replaced every 150 hours
Are you using the Intake Silencer or do you have the airfilters directly onto the carbs?

Let me know what needles, needle jets and main jets are in the carbs and i will advise further.

Niren
Aviation Engines.

[t-bird]

What is the TBO time on a Rotax 618 ?

[Aviation Engines]

300 hours, as specified by the factory.

[Aerosan]

Hi guys

Thanks for the replies,here goes
I got the engine with the plane when I bought it. It was in a box and bought from a company called Vortex. According to the paperwork (the little that was there) it was completely overhauled.
I must say it was in pretty good nick so... The engine has 9 hours on it from the first day I started it.
I was told by one of the guys at the field that the problem id starvation from the pulse pump. He had the same problem a while ago and it was solved by placeing the pump horisotally and not vertical as it is currently. Ill have a look at the jet sizes over the weekend when I go flying.

Thanks for the replies guys :D
Renier
Keep the wings level