[RC-PLAYER]

Hi All,

Past weekend when temperatures where around 28-32 C, I tried staring one of my OS .40 Max engine after about 2 years. The engine started loosing rpm and was extremely hot and eventually stopped. This was an engine I got with one of the lot I bought year back so not sure if it was an inherited problem. So, next, I moved to another one OS LA .46 apparently looked fine as the first one but it stopped with exactly the same problem. This engine is also from the same lot and was never used by me before. The only thing I could think of is fuel. I'm using around 3 years old Omega 15% that I had. I'm now considering changing fuel. Can there be any other reason, please help. I'm getting desperate in getting back to the field after a break of around 2 years.

Thank you.
Navi

[davidmc36]

Old fuel that has some of its important components evaporated away plus getting so hot that it is vaporizing whats left of the fuel part??????

[jtsmash]

Were you using the same fuel tank and lines for both? If so check the lines and also check the fuel tank bung. Make sure there are no air bubbles in the line. Also make sure the vent tube has enough space between it and the top of the fuel tank so it isn't getting blocked off.
I personally don't like more than 10% in .40 and up engines.

[davidmc36]

Also, OS says on an info page fuel that has gotten condensed water mixed into the methanol will tend to make an engine run hot.

[RC-PLAYER]

Thanks davidmc36 & jtsmash for such a quick response.
I have changed the tubing as old were swollen and loose but using same bottle for both. Actually, I found .40 a bit smaller for the plane and upgraded it with .46. The vent pipe is much away from the top of the bottle with no chance of touch the roof and getting blocked. I thing though, the fuel bottle is perhaps 98% horizontal chances of fuel getting into vent pipe ??? not sure ??? even though I kept fuel a bit less than to its max capacity.
I will get a new bottle of fuel on my way back from work today and give it a try, anyways and let you know.
Also, please advice if 15% mentioned on the fuel mean it has 15% the actual fuel or it is opposite ?
Thanks once again.
Regards.
Navi

[jtsmash]

Originally Posted by RC-PLAYER

Thanks davidmc36 & jtsmash for such a quick response.
I have changed the tubing as old were swollen and loose but using same bottle for both. Actually, I found .40 a bit smaller for the plane and upgraded it with .46. The vent pipe is much away from the top of the bottle with no chance of touch the roof and getting blocked. I thing though, the fuel bottle is perhaps 98% horizontal chances of fuel getting into vent pipe ??? not sure ??? even though I kept fuel a bit less than to its max capacity.
I will get a new bottle of fuel on my way back from work today and give it a try, anyways and let you know.
Also, please advice if 15% mentioned on the fuel mean it has 15% the actual fuel or it is opposite ?
Thanks once again.
Regards.
Navi

15% means it has 15% nitro content. see if they have 10% omega or cool power and the engines will probably like that much better!

[Lazy Ace]

I find richening up the engine a bit on those really hot/humid days makes a big difference. 10 or 15% nitro has never made much difference as far as I have seen. For simplicity sake I just buy 15% and run it in everything. Even my YS that is supposed to run on 20% runs fine on 15%. I like pure synthetic except where engines with bushings are involved. Then a little castor works better.

We were running in Florida, Texas and Georgia in much hotter/humid conditions than here and never had any problem.

If the engines have been sitting for a while and have been run on castor/synthetic in the past they may have some residue on the internals that are effecting the cooling.

Sometimes you can wash this residue out by leaving the glo driver attached and opening up the high speed while the engine is wide open until it becomes slobbering rich. After several oz have been through it start leaning it out to where it will run without the glo driver attached. Now you can slowly lean it out until it just breaks clean. After each small adjustment of the needle valve wait a bit until the mixture equalizes in the crankcase and the engine becomes stable. Best to adjust when your tank is half full.

Don't try top rpm (leanest setting) on hot humid days better a little on the rich side.

ONLY MY OPINION
Dennis

Dennis

[RC-PLAYER]

Thanks Dennis. Just realized if only the fuel is the culprit, then I might have to throw out 7 or 8 bottles of them. Or can I add a little castor oil and try using them ? Not sure ?
Thanks again for your time.

[RC-PLAYER]

Thanks Jtsmatch. Will see if I could get my hands on a 10%.

[kip51035]

A lot more information would help!!! Did you re-adjust the needles? What happened when you took the glow ignitor off? Did it loose RPM? Did you try a new plug? Glow plugs come in various heat ranges. Try a hotter plug. Leave your glow plug ignitor on until you have run the engine for a while and adjusted the needles. Some carbs allow a pool of oil to get trapped inside them. Like the guys said try some fresh fuel!