jboomer

I found an old OS .40FX and would like to clean it up to see if it’s any good. There’s some surface rust around the carb and probably inside the cylinder/on the piston as well. I gently tried turning the prop, but it wouldn’t (easily) budge, so I stopped there to come here for advice.

What recommendations do ya’ll have for cleaning this thing up? I would assume I need to soak it in something to free things up and probably disassemble and clean with scotch brite instead of just cranking on things and scoring things up?

Hydro Junkie

Put some antifreeze in an old crock pot and throw it in Leave it overnight on the low setting. Next morning, you should be able to take it apart and go from there

speedracerntrixie

My Feedback: (29)

A crock pot may work out better LOL, actually it is a good way to loosen up a seized engine. When you go to clean it up don't use scotch brite though, use 1500 grit sandpaper with some oil on it. The scotch brite is actually too abrasive. You may also want to replace the two O rings in the carb and the one at the base of the carb. Good luck, let us know how it turns out.

Hydro Junkie

Okay, I fixed my post but you need to fix yours. What does it mean to "ckean up" and engine?

speedracerntrixie

My Feedback: (29)

LOL I guess we both have fat fingers on the keyboard today.

bigtim

My Feedback: (13)

so having just gotten into the world of engine cleaning and in my case rebuilding, if your just trying to loosen up the engine first try putting a little glow fuel in the carb opening, that should help melt the old castor oil gumming up the engine hopefully, also pull the glow plug and put some fuel down that hole as well and let it soak.
also a heat gun can be useful after the fuel has been poured out if its really stuck, I use WD-40 as a short term lube to break parts free but its not a long term storage oil for sure, after run oil or Marvel mystery oil works well for this.
once you have the engine turning,if its turning at all, rotate it without a plug and see how the bearings feel if there gravelly or rough feeling you might want to unscrew the back plate and see if there is any rust, if there smooth throw a plug in it and, put it on a stand, or in a plane, and see if it runs, running a engine heats it up and loosens up all the old fuel residue, a engine with rusty bearings will run but can also make a mess of things if they are bad and cut loose it can seize and in some cases destroy a engine.
bearings are cheap and replacing them is easy with a minimum tool kit for a 2 stroke, YouTube has numerous tutorials for bearing replacement,and if your not ready for that numerous people will be glad to charge your bearings for you.
I have now purchased a sonic cleaner for my engine work it works insane, good for engine parts and many other uses it will even take care of rust with the right mixture in it bearings though once there toast need to be replaced.

a Huge! caution if you put antifreeze in a crock pot to boil your engine which works great, you can never cook food in it again! ever ! its poison! and renders that crock pot unusable for food .
I have one in my shop that's getting placed in the trash now that i have my cleaner

tbone4343

My Feedback: (4)

heat , i use a small butane tourch and warm it up then oil it with regular oil it will loosen up

tbone4343

My Feedback: (4)

dawn power disolver works great but hard to find in stores still see online though

jboomer

Thanks all! I ended up swapping between heavy oiling with LPS, WD-40, and 3in1. The engine loosened up nicely. However, the carb seems to be frozen solid. I’ve removed it from the engine and soaked it from both sides, but it won’t budge. It’s partially open, but even a little assistance with trying to pry it open further hasn’t helped. I haven’t tried heat yet...that’s next.

J330

My Feedback: (3)

Heat works. Avoid prying things.

I have an old Rossi 40, couldn't get it apart to save my life. Thankfully, I got a buddy in town that's better at this than I am and gave it to him, with a dozen jelly filled doughnuts and a spare flight box I had laying around for a thank you. I'm not going to lie. He got it apart. Only took 3 days, so I didn't feel so stupid that I had failed. The bearings didn't have another flight left on them, no telling what would have happened he said, but everything else looks good for another 20 years we think. Tolerances are nice on this engine. Compression is like the day it broke in. Those jelly doughnuts are like gold down here.

Boca Bearings. I put my business license to use, got a discount, $9 for the bearing set. Ordered several sets for my mediocre OS performers in the house that are ARF worthy. 6 planes now ready to fly and counting. Waiting for a green light at the flying field...




The polish job on the outside? We use Mr. Metal. Works like a charm. $4

​​​​​​https://www.homedepot.com/p/Mr-Metal...7284/306057489

jboomer

that looks soooo clean! Nice work!

unfortunately, heat didn’t do it either. Have it soaking in mouse milk now...fingers still crossed.

i have an OS .46FX that suffered the premature peeling cylinder wall about 15 years ago that I’d like to salvage too. Haven’t explored the cost of replacement cylinder sleeves recently, but back then, it wasn’t cost effective. That’s how I ended up with the .40.

I’ve just started getting back into RC. Bought an electric (UMX Ultrix) and the associated gear to run it and it’s been fun. However, I learned on glow and would really like to get my son involved. Seems like glow is becoming even less popular, more expensive, and more difficult to find though. Electric, specifically the heavier (more stable) stuff, is pretty expensive too.

jboomer

After soaking a couple extra hours in mouse milk, then high heat, carb is unfrozen. Engine rotates smoothly and cylinder wall is clean. Only thing left is to run it up. But, the glow plug is toast, so will go ahead and order a couple and some new silicon tubing to replace my old stuff. If the engine runs good, then I’ll need to rebuild the vertical stab on my plane as mine was broken off years ago. Servos/radio all seem to still work well too.

J330

My Feedback: (3)

I've flown glow since the 70s. Haven't abandoned it yet. The cost for lipo and chargers for me, plus the learning curve while I fry things, no thanks. It's cheaper to stay where I'm at. I already own dozens of engines, nothing else to buy. I also like flying a stronger, lighter balsa frame than foam. Balsa and glow is how I've always enjoyed this hobby. You'll find the forum classifieds are the last hobby shop to fill your needs. As far as fuel costs, it's not a deal breaker for me. It just shot me out of the .60 size class and down into the .25 and .40 size. That Rossi 40 is going to suck 1 ounce a minute though, so I will use it sparingly.
4 stroke engines, sip fuel. I had an Ace 4-40 biplane with a Saito 56 on it and could get 20 minute flights, and come in with almost a half tank of fuel left.

jboomer

Well, decided to clean up the old glow plug that was originally in the engine and discovered it’ll still heat up! Put the engine on the old busted plane and filled the tank about half full with fuel intending to see if the engine will run, but discovered the needle valve is also frozen solid.

Not sure how to fix this one. I have it completely submerged in a lubricant/penetrant (mouse milk), but I think adding heat was ultimately what freed up the carb. Don’t think I can do the same with this as half of the needle assembly is plastic and I don’t want it to melt. Anyone have tricks to this without risking permanent damage?

J330

My Feedback: (3)

PB blaster helps. Do not use a lot of heat. 150 - 200 degrees tops. 40 FX has a cast needle on the backplate, not a chrome piece bolted on like an LA, right? O ring can swell, so just put another one on, but crank out the needle with pliers, I've never had a problem with needles on a warmed up engine that has PB blaster on it.

jboomer

I appreciate the advice! It’s an LA, not an FX, I misspoke. Yes cast needle. I’ll try some easy heat applied directly to the needle.

J330

My Feedback: (3)

You'll likely crack the plastic housing forcing the LA style, so don't go nuts on it. Not the most expensive housing to replace though. (Link)
At least you have an engine that has no internal ball bearings, or rust issues to worry about now. Are you going to use this on a trainer?

​​​​​​https://www.towerhobbies.com/cgi-bin...p?I=LXMW57&P=7

jboomer

Something affordable! Lol

yes, it’ll be going on a trainer. If I can get it to fly/run reasonably reliably, I’ll teach my son on it.

jboomer

Was able to get the needle freed up and the assembly cleaned out and the engine now runs! It’s odd though, I can plug the carb, spin the prop, and get fuel to the carb, but I can’t get the engine to start this way. I have to pour fuel into the head and then quickly get the plug in and spin the prop to get the fuel to the carb and then start it, in order for it to run. I’ll have to freak out the book and see if I’ve got something set up wrong. This engine was originally mounted upside down in a different plane.

im also starting via the old stick method, so that slows things down too, lol.

bigtim

My Feedback: (13)

might help to get a electric starter some guys are hand starters but for me a electric is the way, I also run larger 4strokes so its easy to feed fuel and get going, it also keeps the fingers out of the knives, cant say it enough youtube is a great resource for engine tips especially carb issues, a well broken engine will flip over and fire up when the carb is dialed in, if you need to prime the engine you should be able to put some fuel in the carb to get it going, too much fuel in the cylinder and putting the lug on can cause serious problems and can cause piston and rod damage.

J330

My Feedback: (3)

The most fun I have with a 4 stroke is the fact I can leave the big flight box home and just back flip those things.

bigtim

My Feedback: (13)

My 4 stroke rebuild new crank bearings, timing gear bearings, connecting rod and pin, it was so gummed up and rusty it would hardly turn over, cam bearings were seized which is not common, got it on a deal from eBay and now it’s fresh hopefully I can get a run in tomorrow on my stand to dial in the carb because I have 2 more to go through and rework hopefully not as much as this one life is good One note the rebuild is fairly inexpensive the costly part was the rod and pin which was 35 bucks

bigtim

My Feedback: (13)

a little inspiration, for the beginner rebuilder, I have now rebuilt motor #2 and on to #3 is on the bench, so I just ran up #1 on my stand got a clean 9,500 RPM tuned back to 9100 ran smooth as silk with a 1800 idle just put put putting along its amazing what a new set of bearings and a clean up will do to a old engine.

stuff like this is a good distraction from the COVID-19 blues, going to run up #2 tomorrow, had to buy a new/used case off ebay I will take a picture of my test stand it cost me virtually nothing since I built it from scrap plywood.