1QwkSport2.5r

This is all good to know. I'll call Fox on Monday. The Fox has incredible compression for its age and unknown flight hours/runs, so I can see how they dont wear out very fast if ran properly. I'm excited to hear these things fire up. Aside from the fuel considerations, are there any other things I need to know before breaking-in this K&B? Also, is there a way to determine a prop's pitch? This K&B came with a dozen wooden props (beech) 12" in length but there are no markings on them to tell me pitch. I was going to use one of these for breaking in the K&B, and when it goes on the airboat, I'll get some nylon props since the water will disintegrate the wood props. I am unsure of what pitch props to use.. I know some plane guys have run up to 14-6's on these .65 sportsters, but I dont think I'll need a prop that big.. I'm kinda thinking a 12-8 and a 13-6 to start off with.. The boat should weigh in around 5-6lbs rtr.

rcdude7

My Feedback: (264)

When you call fox, you might want to order some "Dukes fuel" it is a all castor fuel and is perfect for the two engines you have there. The fox you have is a iron piston type and it will not live with synthetic lube. Since you say it has good compression, someone probably already ran it with the proper fuel and did'nt ruin it. Enjoy.

w8ye

My Feedback: (16)

The 65 Sportster was rather unique compared with other model engines especially at the time of its introduction.

They are not known as RPM engines

Once you get used to it, The Sportster will be a fine engine.

1QwkSport2.5r

Thats what I've heard.. The "poor mans 4-stroke" swinging huge props at lower rpms. Some guys have talked crap about 'em, but a lot of other guys have ran many of them and never had a problem. Not big on performance, but good on longevity and brute snort... I think it'll be a fine engine. I think the best part about these engines, is the little stamping on them that says "made in USA"...

w8ye

My Feedback: (16)

Head the name "Sportster"

It is a sport engine for fly around planes

Learn it's ways and you will enjoy it. Try to make it something it is not and you will hate it.

huck1199

For the K&B .65 Sportster add 4oz castor per gallon of fuel that allready has 18% oil synth/castor. I like Omega fuel. 

1QwkSport2.5r

I'll see what I can find locally. Worst case scenario I'll order it online. I am not in a big hurry as I'm still building the boat..

w8ye

My Feedback: (16)

if you get impatient, Do like the post above says and add 4 oz castor oil to regular fuel

You can even get the USP castor oil at the drug store

1QwkSport2.5r

I already bought some from walgreens Its even a 4oz bottle.

w8ye

My Feedback: (16)

Good move

1QwkSport2.5r

I thought I'd post a pic of my flatbottom boat build - a little off-topic but I'm all excited about it.. 32"Lx18"Wx3"H. Main frame is done, still have supports for the skin to cut, but I'm going to do this when the frame is glued together and cured.

MrGreenSpeed

I have 2 fox engines that look just like Yours, one is a .29bb and the other is a .36bb
I run mine on 10% nitro and 24% all castor oil.
The 29 had a 29 on the side of the mount flange,
The .36 didn't have any markings so I pulled the head and button and measured the bore & stroke to find out which one I had.
Both are great running engines, but any hard landings and You'll end up using a strap type muffler.

I also have the same style fox 40bb that has the 2 bearing crank ( New never run.)

Jeff [8D]

1QwkSport2.5r

I wont be using my aircraft engines in an aircraft.. I'll end up using them on airboats... I dont have the money or space to run a plane..

MrGreenSpeed

I have a tt36 on a 2" pink foam and coroplast flat bottom air type boat lot's of fun

MrGreenSpeed

Ps.
It goes almost as fast on wet grass as it does on the water [8D]

1QwkSport2.5r

Sweet! I am thinking I'm gonna have a lot more fun with a boat than a plane... This design of boat I'm building will allow me to run an air rudder on land or snow and water rudder in water.. I still have to make the rudders and engine stand, but its coming together pretty quickly and nicely. I'm waiting for epoxy to finish setting up on the main frame before I can start to reinforce the rest of the frame and skin it. I'm going to pull the 65 apart and clean it out and re-assemble it with some fresh oil and gaskets.

1QwkSport2.5r

what kind of fuel do you use in that TT?

MrGreenSpeed

Wildcat 15%nitro 18%syn/castor mix fuel.

Jeff

1QwkSport2.5r

Cool.. I've been told to run 5% nitro/22%oil (castor only) for break-in on the .65 sportster and after break-in no more than 10% nitro and still 22% oil... sound about right?

MrGreenSpeed

Yes
The K&B .65 sportster is a plane bearing engine and like a lot of castor oil.
They also tend to leak a little oil out of the front bushing area just behind the prop driver.
They have a hand chromed aluminum piston, and an aluminum cylinder, with No Liner,which is backwards form most R/C engines that have nickel or chromed cylinder sleeves and an aluminum piston.
Break it in and go have fun with it.
Jeff

spaceworm

The early K&B 65 Sporster did not have any bushing for the crankshaft in the nose of the crankcase. Later ones did, and K&B/MECOA would exchange an early case for a later one to the original buyer. I have an early one and have thought about getting a new case, even though I do not qualify for one for free. Mine does throw a little fuel out the crank at the prop driver, but not yet excessive.

Speaking of liner-less cylinders, I saw a really nice VEGA station wagon today, are they being collected? I did not think any survived rust and disdain.

Richard

w8ye

My Feedback: (16)

The cylinders/pistons in the vega were a backwards affair also.

A few people got along rather well with the vega but most people had the feeling that it was the worst car GM ever tried to sell.

1QwkSport2.5r

Okay.. back to the original subject of the thread - The Fox .40. I found out through talking to FOX Mfg. that this is a Series V Fox .40 with single BB in rear of engine. It was made in 1983, and uses 1 setscrew to hold the carb in. Everything was sealed with RTV. I tried running the engine today since I reassembled it and could not get it to run for any length of time. Seemed to flood out. I got 2-3 good 10 second bursts but thats it. The rest of the time I got it to fire 3 or 4 times and it'd quit. I thought the tank was too high so I dropped the tank down a couple of inches and that seemed to help but it still wont stay running. If I get it running, it usually ends up spinning in reverse and as soon as you hit the throttle it dies. MC59 plug and Sig 5%nitro/20%oil fuel. I haven't put fuel tubing on the needles yet, I will do this tomorrow. Anyone got a ballpark starting point on the needles? I tried 1.5/3 turns low speeed/high speed respectively. I tried 2/3, 2.5/3, 2/3.5, 2.5/3.5, 2/4, 3/4.. It didnt really seem to matter where I had them.. it behaved the same way each time with it being a little better at the 2.5/3 turns (high speed) and 1.5-2 turns low speed.

Quite a few people have said this engine is pretty noisy... I think its quieter than the K&B .65 w/ muffler baffle in place.. I expected it to be rappy but it sounded really good considering its almost 30 years old.

I did find out through hours of searching what the carb should be set at for an initial setting. I'm still waiting for the owners manual to come from Fox. My main question now is why does it spin in reverse so much? Sometimes it reverses and other it just stalls. If I try starting it clockwise, it will mostly start running in the proper direction.

1QwkSport2.5r

Well, I ran this engine today. Once I put the fuel tubing on the main needle to help keep it from leaking fuel through the threads of the needle. For some reason, It does not like the pressure line connected. Is this a normal thing for these engines? It will wind out with the line disconnected. Transition is a tad rough, but it gets it done. One problem I do have that I need advice on: While running at WOT, I tried setting the high speed needle, but nothing I did to the needle rich or lean changed how the engine ran. I brought the high speed needle out to 5 or 6 turns and it ran no different than at 2-3 turns. Low needle (according to some fox literature I found, you start the low speed out seated) is out about 1/2 turn right now, but here too no adjustment I made made much of a difference in how the engine ran or idled. I tried 5% and 10% nitro with better results with the 10%. The whole engine is sealed with RTV including the carb base and the setscrew holding it in.

1QwkSport2.5r

Nobody has any help?