Cox Black Widow
 

I have a question about a Cox Black Widow engine. Can I run my regular 4-stroke SIG fuel through it?

Thanks,

galesc

RE: Cox Black Widow
 

SIG says the 4-stroke fuel in not to be used in ANY 2-stroke engine. The little fellers like their nitro, 20% or better . Max H. :)

RE: Cox Black Widow
 

My bad, I meant 2-stroke engine fuel. So the Cox engine likes a higher Nitro percentage? I think I have 15%. I also have 20% for my R/C trucks (but that has a lower oil content).

RE: Cox Black Widow
 

They make fuel that is designed for just 1/2 A engines. For the reed valve engines you need the right lubricate and nitro. I am not sure that 15 per cent will work at all. Good Luck, Dave

RE: Cox Black Widow
 

Hi!
You can use whatever fuel you like in all COX engines! Even 0% nitro!

They however function best with more nitro. 15-30% nitro is what I use in my Babe Bee and Tee Dee engines.
It's also important that you use at least 20% oil in the fuel. I have run several Black Widow engines on 15% all syntetic oil (Motul "Micro"
and Aerosynt 2 and Aerosave) that i use for my other engines, but these modern synthetic oils is not that good for the old COX engines. They seem to run more reliably (perform better) with 20% Castor oil.

5x3 is a good prop size or 6x3 for a slower, larger flying model!

RE: Cox Black Widow
 

They run fine on 15%, and they last longer. Best to use a fuel with castor oil. You'll get more power with higher nitro, though. Whatever you do, don't use Cox fuel. It's extremely expensive and you don;t get anything extra for that extra money. I've used Norvel 25%; don't know if it's still made, though, as it's been a couple of years.

RE: Cox Black Widow
 

As I recall the little pint cans of fuel we used to buy was 30%?? Not sure these days and TD didn't have the blend on the lable/can. I use my standard 15% nitro 18% oil power master fuel in my 1/2A engines and it works just fine.

RE: Cox Black Widow
 

I've used 10 & 15 % in all my small engines with no problems. As said you may want to be sure you have about 15 - 20 % oil.

If I remember right the sig fuel in the smaller cans was 25 % nitro. ENJOY !!! RED

RE: Cox Black Widow
 

Caster is a must IMO for the ball and socket joint of the con rod. I was thinking 25% nitro was what the Cox fuel was???

I used to run 65% nitro when I was doing some racing. You had to pre-fit the piston/cylinder first, other wise the piston would stick and or, beat out the ball and socket joint. I had a "special" tool to reset the socket. Got 'em to tight sometimes though[:@]:D