Neddy191

My Feedback: (2)

I've been on a sabbatical from flying for about 4-5 yrs. I have a trainer I want to start flying again with a OS46ax. When I first got it back out it was gummy feeling but after hitting it with a heat gun and turning it over several times it loosened up nicely. I replaced the lines, seal and clunk in my fuel tank. I have a 3 line set up 1 to the carb, 1 to the exhaust, and 1 to a fuel dot.

I can't get it started. I've reset the high speed needle valve to about 1.5 and then 2 turns out with no success. I can get it started momentarily if it put fuel in the carb but it won't stay going. I think it might be a problem drawing fuel from the tank. I've double checked and there are no kinks in my fuel lines. When I try to prime the engine by covering the carb and turning over the prop I don't ever get fuel to pull. I tried disconnecting the fuel line from the back of the needle valve assembly and drawing on it with a syringe and it pulls ealisy. When I do the same from the back of the carb through the needle valve assembly and its more restricted (logic tells me this should not be a big deal and its a valve and it's job is to restrict flow)

Any suggestions would be greatly appreciated.

opjose

One of the things that is often overlooked is clogging of the nipples, particularly in the muffler nipples.

Clear these out with a inter-tooth micro brush ( available at a drug store ).

Then try turning the engine over at full throttle with the muffler exhause plugged.

You should see fuel "pulse" slowly towards the carb at every flip.

Neddy191

My Feedback: (2)

Thanks for the reply, as you were typing I was going over it and found that the nipple on the back of the carb was blocked. Cleaned it out an now she pulls fuel and cranks up. Gotta find info on tuning now. She'll run at over 1/2 throttle but under half throttle she dies quickly.

jester_s1

Low speed needle is either gummed up with old castor or just set too lean.

Neddy191

My Feedback: (2)

I'm going to assume its gummed up with castor because I never touched the low-speed needle through many gallons of fuel in this engine and it alway ran great. Whats the best way to clean it?

Gray Beard

My Feedback: (-1)

I just hit them with a heat gun then see if they will start and run. If they do fine, if not then I pull the carb and soak it in fuel for a few days then take it apart and clean it. sOMETIMES i WILL JUST TAKE THEM APART AND CLEAN THEM WITHOUT SOAKING THEM. Heat will often allow the engine to free up but crud in the carb is there to stay. I run my engines dry before storage and often clean them in alcohol then oil them up while I am re-assembling for storage.

freakingfast

My Feedback: (3)

You could still have some gunk stuck just ahead of the low speed needle, inside of the inlet.

Another thing, put a fresh glow plug in it. Just because it glows or starts doesn't necessarily mean the plug is good. Ive seen people several times struggling with tuning an out of storage plane "it ran great the last time it flew". Funny thing about used glow plugs that were put away with the engine, often they seem to change with time.

Gray Beard

My Feedback: (-1)

Been There!!!!!!!!!!!

jester_s1

Excellent point about the plug. Tossing the carb into some fuel for a couple of days will loosen up anything that's stuck inside those passages, and a shot of air should clear it out.

ameyam

If the carb is gummed up, is it a good idea to soak it in fuel overnight, then use an electric pump to pump fuel through to unclog it? Will the same technique work to clean the passages of LSN and HSN? Asking because I am myself soon going to clean a gunked up engine

Ameyam

bill_delong

+1... Ialso have a can of "Berryman's Carb Cleaner" that I will dunk my carb's for 30 min as well. Be sure not to dunk any rubber seals in Berrymans, it usually cleans so well the engines literally run like new. Comes in handy for weedeaters and lawnmower carbs as well

jester_s1

Yes Ameyam, flushing the carb with fuel works too. Compared to gassers, our carbs are really simple devices, and the passages are pretty big. The HSN can get gummed up which will make getting a good tune a pain, and the spraybar can get clogged. I suppose the LSN could get gummy too, but in most designs even if it did it would still work fine. I've hooked up a fuel pump before to the carb and forced fuel through it to make sure it was clear. You just turn the hsn out fairly far and open or remove the throttle depending on what it takes to get the fuel flowing properly through the spraybar.

Gray Beard

My Feedback: (-1)

I found soaking them for several days worked better then just over night. Amey, if you have a drug store go in and see if they have Ear Flushing Bulbs. I have one of those and I stuck a piece of brass tubing in it then attach fuel line or gas line {as required} to flush things. You get a LOT more pressure with one then a pump. As a kid we used these things to fill our fuel tanks in out 1/2A engines. To show you how well it works, I had an engine that had a vacuum leak. I could put my finger over the carb and it kept running? I filled my bulb with fuel and attached it to the carbs intake and with my thumb over the carb and gave the bulb a squeeze. The fuel was bubbling out of the steel sleeve insert that the carbs hold down screw threaded into, it was a press fit part in the case. I cleaned the case with acetone, heated up the case with a small torch and used my fingers to press in some JB Weld into/over that insert. After that the engine ran perfectly.
I also use that bulb for flushing out gassers carbs and the regulator in my YS engines. The thing cost about $2.00 but for me it is a priceless tool. Comes in handy out at the field too. As someone that rebuilds his own engines it's a must have tool.

Neddy191

My Feedback: (2)

It ended up that the LSN was all gunked up. I opened it all the way and could see crud on the tip of the needle. A little fuel soak and it was clean. I used the blow through the carb with some fuel tubing method and reset the LSN and to my amazement when I cranked it back up last night it ran perfectly. A few tweaks to the HSN were all I needed. It idled nicely and had quick smooth transition from idle to WOT. I was surprised I didn't need to do any tweaking to the LSN.

Gray Beard

My Feedback: (-1)

That's great. Most people think you must strip an engine down and completely clean them and replace the bearings after long storage. This is often the case but unless they do as you did and just get them rolling over with heat then trying to fire them up to see they are doing something that may or may not be needed. I have been given old engines that were completely frozen up and done as you and they fired right up.
If you know you are going to store an engine I have found that just running them dry then openine the back plate and flushing them with the drug store 91% alcohol and then oiling with Marvel air tool oil you can store them forever. I have tried to flush them with alcohol and n ot oiling to see what happens over time. Leaving the bearings dry isn't a good idea. My test engine bearings felt rough and I could hear them when I rolled it over by hand. I just shot some Marvile Mystery oil in the carb and head and rolled over by hand until they smoothed out then used my starter and rolled it over a bit more. The engine was fine after that. I also live in a dry desert without humidity so I never encounter rust.
You did it all correctly but keep your ears open for the bearing rumble as you use your engines. Sometimes that old Castor can booger up the bearings and it takes some time to show itself. Just a heads up.

opjose

No truer words!!!!

Often they'll look inside see the rusty looking gunk on the bearings and declare them shot.

I'll just shoot some WD 40 in, wait a few minutes, rinse the engine in VERY HOT water then shoot in Dawn Power dissolver.

I'll let the engine sit for 10 minutes and swirl a soft bristle brush inside... then rinse it again with hot water.

This is repeated if needed. Normally the insides end up shiny and new looking.

Finally the engine is dryed as much as possible, then I shoot in WD40 to flush out water and finish with a bit of glow fuel or oil.

All of the perceived grittyness disappears and the bearings look good as new, so does the engine!

Neddy191

My Feedback: (2)

Just a pic of my LT-40 with said engine on the stand yesterday just before I finally got it fired up and running well.

Gray Beard

My Feedback: (-1)

Your a bunch luckier then I am, I was given a couple of OS .91 FS engines that were a friends that moved from here to Texas. I think he was a bit spoiled here from the lack of Humidity but when he sent these engines to me and I opened them up the bearings were packed with a combo of rust and old Castor oil. Nothing removed the gunk from the bearings but I tried. Then I just said to hell with it and put one in my Kaos. It ran great but I could hear the bearings in it growling. No mater, I flew it for about two years until one day I did a fly by and could hear the bearings screaming. I landed and didn't use that engine until after a rebuild. It's running great again but those bearings could have let go at any time, I bit the bullet. The other one I looked at and it looked the same way so I just ordered new rings and bearings for both engines. Now I have one in a trainer and one I loaned out to a friend for his Cub float plane. With bearings.com prices sometimes I will just replace the bearings just for grins but I will still just run them depending on my needs. Right now I have so many four strokes not doing anything I will just rebuild and store them just for the fun of it. Rebuilding these little engines is relaxing for me?
I'm thinking it must be the dawn in the boiling water because I use boiling water to heat the case and it doesn't do anything to the gunk.

ameyam

Good to hear I am on the right track. We dont have those cleaners you mentioned (except WD40), so I simply put the whole engine (disassembled) in fuel, then pump the same through all the parts, Then simply drain, oil and leave at that. Did the same with my DLE20 as well (used petrol there ofcourse). In addition, I put in plastic bags that I tie to be air tight, then put in the original box, then seal the box over with packing tape on all edges. It may be a bit extreme but so is the monsoon humidity. Since I started doing this, the engines remain clean and come back quickly after the off-season

I did the same to a couple of guys engines (their engines were in yuk condition) at the field and they run just fine as well

Ameyam

jester_s1

If you didn't know it already automatic transmission fluid makes a good storage and after run oil. There's something about the chemical formulation that makes it creep all over a piece of metal, so it will work its way into every little crevice and displace any water that's there.

Gray Beard

My Feedback: (-1)

Thanks Jester, it is also available all over the world. It is a good after run oil. One of the magazines did a test on oils and Marvel mystery oil and there air tool oil came out as number one. One of them removed rust and grime better then the other and one made a better storage type of oil. Being an old fart on meds I can no longer recall what one did what better? I use the mystery oil when rebuilding an engine, just because I have a little bottle.
A little warning about WD-40. It is a penetrating oil and evaporates without leaving behind any protection, ATF and air tool oil is much better for storage then WD-40. I think I read that Ameyam was using sewing machine oil, that is a light weight oil and is a pretty good storage oil. I think it is like air tool oil, about 5 weight.
Amey, it's monsoon season in Vegas too. {Nothing at all like yours} but it can be raining so hard I can't see the house across the street then just quit, then the sun can come out and it will be about 105 degrees. I like the heat, up to about 100 but I just hate it when it is humid. I don't bag my engines per say but I have a few of them in those plastic containers that the dish washer soap packs come in. They seem to do the trick and I can stack them under my bench.
When I moved here I didn't know Nevada had a monsoon season. We get most of our water this time of year, it was a total surprise, a little something my wife and friends never mentioned to me. They thought it may have changed my mind about moving here. Trust me, the monsoons are way better then the snow and rain I had living just outside of Yosemite National Park.

opjose

Yeah the combination removes any light rusty looking deposits that will screw up the bearings. That is also why loosening the deposits with a brush is important, so you are assured of getting at everything... An epoxy brush suffices.

Normally the bearings and the races look clean afterwards and there is NO grittyness or play.

Next time you run into an old engine, give this a try before you resort to pulling the bearings.

Many times you'll find the bearings do not need replacement at all, just a good cleaning.

I've salvaged black stained and siezed 6yr old+ engines from junk boxes, where people had thrown them away at meets... A day later the same engine is clean and running perfectly thanks to Dawn Power Dissolver.