Frenzy 90 Overheating

[ebonicrobot]

My 90 keeps on overheating and I Think its because of the fan shroud. Is anyone else having problems like this. I have to keep my OS .91HZ needles 2 turns out to keep the engine at a resonable temp.

[Raptor30_V1]

Hi,

Pretty thumb question:

- what do you mean by running hot ?
- do you have a leackage in the fuel system somewhere ?
- where's your iddle-mixture-screw ?

The second is pretty common, the third issue too ..
I have an YS-91 installed and engine never ever runs hotter than 110 degrees Celsius.

Almost 99% of people flying nitro's never noticed, the interaction inbetween the iddle-mix-screw and the main-screw. Even though engine manufacturer's marketers will tell you about the precision of this engines carbs .. the different needles interact pretty much ..

So if you checked all of your lines, no engine parts wear and plug is ok, maybe you closed your iddle-mix-screw pretty a lot in order to *tune* your iddle ?

Best Regards,
Oliver

[ebonicrobot]

My idle mixture screw is at at factory setting. I checked the lines I had Hayes clunk line installed in both tanks. Do worn rear bearings cause overheating? After a few climb outs I check the engine temp and I was geting a reading of 230F at the head. Way too hot. I'm going to replace all lines and check again.

[Raptor30_V1]

Hi,

If you really make steep climb outs at high rpm and pitch, 100 to 110 degrees Celsius for an OS-91 can happen ..

No power but overheating sometimes can be related to a (too) high compression. In order to find out, put some additional glow plug gasket inbetween the plug and cylindre-head and repeat steep climb outs. If power gets better and even at lower temps, you need to reduce your compression, mostly done by adding shims inbetween the engine case and cylindre head.

Did you play around with some different plugs ? Most peoples use some OS no.8 on their OS-91 engines, why not trying an Enya no.4 instead, OS no.7 or even an Enya no.3 ?

Checking the fuel system afterwards is not a bad thing neither.

Most of the time, when a main bearing starts to wear, it's IMO not the temperature change to be the first sign, then the sound of the engine changing slightly ? Not for sure, monitoring temperature isn't wrong.

Best Regards,
Oliver

P.S: Some people seem to use the TT fan on their F90 V2s, I wouldn't try this before you checked all of the other points .. Thunder Tiger 90 fans of the older Raptor series should work, but there might be 2 different systems, one of for OS- and one for Yamada-engines ?