Fuel changing color (while running)?

[fstnd]

Hi, yesterday I ran my HPI trophy truggy with the stock 4.6. All great but, why did the orangy merlin fuel change to a red color after a bit of running?

It's the same fuel in the tank and in the filling bottle.

oh and is it normal that after running the car and opening the fuel cap you see smoke? You can also see a bit of it on the picture. I have a small problem with this tank: when pushing down the cap, there is a absolute vacuum, but when not pushing, there isn't. When running, I could see some smoke coming out of the cap. Probably from exhaust?

 

[Chubaka]

Can't say on color. The smoke is either a little exhaust from pressure or condensation. I'm betting the second. Cold fuel, warm motor and hot air pushing the cold fuel.

My nitros do it too, it's normal.

If you have it coming out the closed lid, I would get a new tank or rebuild kit for the lid. If your tune goes whacky, check that first.... Not to mention dirt and dust entering.

 

[tudordewolf]

Hi, yesterday I ran my HPI trophy truggy with the stock 4.6. All great but, why did the orangy merlin fuel change to a red color after a bit of running?View attachment 168408It's the same fuel in the tank and in the filling bottle.View attachment 168410oh and is it normal that after running the car and opening the fuel cap you see smoke? You can also see a bit of it on the picture. I have a small problem with this tank: when pushing down the cap, there is a absolute vacuum, but when not pushing, there isn't. When running, I could see some smoke coming out of the cap. Probably from exhaust?

I've noticed my blue-tinted Sidewinder fuel getting bleached almost grey just sitting in the filler bottle on a sunny day. I would guess that it's the UV light, maybe even a deliberate feature to reveal if the fuel has been improperly stored.

My takeaway was that I should shield the fuel from sunlight even when I'm just bashing for an hour, since the UV will also break down nitromethane.