Microlighters

Is there someone that can give me guidance. I have the following problem with my Rotax 912 ULS.

Ad normal operating revs 4900rpm the oil pressure is 65 - 70 psi. Sins last week for some reason the oil pressure "jump" to 90 - 110 psi for max. 5 seconds and then back to normal for +- 5 min, and then up again for 5 seconds etc etc.
What is the reason for this, and is it harmfull to the engine.
The engine has done only 180 hours. I have a MGL oil pressure gauge.
I have already replace the oil and oil filter, and and the problem still exist, at 1800 rpm.

Please help me.

This might be your Oil Pressure Sender - VDO or the pressure relief ball and spring.

Thanks, I will replace the VDO tomorrow. I have allready clean the ball and spring.

Comet sell a fix for the ball and spring, part 100857230, Oil Pressure Control Valve, about R180. replaces the ball and string. I am thinking of moving my VDO off the engine and mounting it on the firewall, with a flexible rubber tube connecting it to the engine. I replaced two VDO sendors in 100 hours

Agree with Morph, I am on my third VDO sender in 500 hrs, next one will go on the fire wall.

I enquired about an electronic alternative which is available, and even these are not trouble free.

In my experience, the capillary tube gauges are more reliable but make sure you protect the capillary tube.