1QwkSport2.5r

You would hate running bushing crankshaft engines then.

Perry USED to make carburetors for OS engines. Maybe an email to them to see if they still do. My OS .60 FSR (ringed) has a backplate mounted Perry pump and Perry carburetor. It is being removed in favor of a standard carburetor though.

the Wasp

My Feedback: (1)

I have a GP 40, it has bushings, it doesn't leak

Jim

the Wasp

My Feedback: (1)

I see now on the Perry site they do have a Carb for the OS 61 FSR, but I would have to call to find out if the Barrel is the correct size, I don't want to loose power,, but, for like only $18 I can buy a Perry Remote Needle

Jim

aspeed

Jett has a nice remote needle too. I never liked Perry carbs with their knurled mixture knob. You can use a wheel collar with a screw and a deburred end, and just put it over the tubing, just for an emergency or test. I have a few T Tiger .07s, Ucktam/MDS and old Foxes that leak on the crank. A little is desirable on a BB engine to lube the front bearing. Some newer motors have a small hole or slot that goes to the base of the carb to slurp this back in. Sometimes it is too big and it will not idle low enough to stop.

1QwkSport2.5r

Then it isn't really broken in good then. Bushing engines always leak when they're running good - it means the bushing is getting proper lubrication. Bearing engines are no different except they don't leak as much from the bearings. If an engine doesn't leak from the front end at least a little bit tells me something isn't right. YMMV.

1QwkSport2.5r

The Perry carb that came on my .60FSR had brass fittings inserted into the neck of the carb to allow fastening to the engine. The only problem I see with this setup was the brass fittings protruded into the throat of the carb which would alter the airflow into the engine. I would not opt for that setup - I'm not a fan of Perry carbs.

Propworn

My Feedback: (3)

I have yet to find an after market carb or needle set that worked as well as the OS stock items on a stock engine. Modified engines can be a different animal. Swarf from the manufacture of the fuel tank can contaminate the carb even if new and unused. Flushing a new tank before assembly and again before final installation is good practice. An in line filter close to the carb as mentioned earlier if practical is not a bad practice. Filtering your fuel into the model is important. When de-fueling are you going through the same filter? If so you may be trapping contamination on the wrong side of your filter only to push it into the tank of your next fill.

No matter how careful one is contamination can find its way in. Even with an inline filter and a filter on the filler line I found a darn cat hair in the fuel spigot on the carb LOL.

Dennis

jaka

Hi!
I find it very hard to understand that an OS .55 engine (or any engine for that matter) cannot be set to run properly with the carb it was equipped with as original.
It would be nice if we could get pictures of the engine installation.

the Wasp

My Feedback: (1)

when I say my GP didn't leak I mean it didn't leak to the point that fuel/oil was pushed all over the engine compartment, it may have leaked a tiny bit, after years I tore the engine down and cleaned it, the bushing was/is getting enough oil,

BTW, I don't know about other engines, but the Bushing in this GP 40 is over 1&1/4" long, I would guess some other engines are too

well the engine did run fine in it's younger years,, but today>>>>>>>>>>>>>>>>>>>>>>>>> there is something wrong with it !

I bought that 61FX new, I had it in a 4 Start 60, I sold it to a friend that had been flying for 30 years, he put it in the ShoeString, then I bought the ShoeString and engine from him, the engine is mounted no different than any other glow 60 size plane I have seen,,

yes I do use filters, and I under stand that Swarf can produce a problem, but i cleaned both the needled assembly and the carb very well when I replaced the bearings


Jim

Propworn

My Feedback: (3)

Well you've done all the basics right and everything is tight. One more question when you disassembled the engine to do the bearings did you reassemble the rod and piston in the same orientation? Getting the rod backwards sometimes causes problems. Some engines the rod bushing has a chamfer or radius that needs to face the counter weight. Not sure about your engine though.

Dennis

the Wasp

My Feedback: (1)

yee-up, I got the Rod in correctly,, I have to replace the front bearing again, it leaks just too much, this time I will buy an SKF bearing, and I will buy a quality after market remote Needle and mount it off of the the engine mount close to the Carb

Jim

aspeed

A bearing is not really a seal, although you can buy them with one. It is more of a dust shield. I would leave it on the front of the bearing but not the back, and pop both off the rear bearing if equipped with shields if you think a new bearing is really needed.

Propworn

My Feedback: (3)

RESETTING CARB TO BASE SETTINGS

I myself have fiddled with both high and low speed needles to the point I needed to return to some form of default setting. A much more experienced modeler showed me a simple system that works for all 2 stroke carbs with a low speed needle. Air bleed carbs are different and this doesn’t work.

Before you start you will need a short length of fuel tubing and a 1/16 drill bit. I also recommend a new glo plug and fresh gallon of fuel.

Back the low speed needle out all the way and the throttle stop so the barrel closes all the way..

Close the throttle all the way. Hold it closed.

Carefully turn the high speed in until it stops/bottoms out. Do not force.

Turn the high speed needle out 2 to 2 1/2 turns. This rough sets the high speed setting.

Now to set the low speed needle.

Use the 1/16 drill and insert down the barrel of the carb. Close the barrel until it just traps and holds the drill in the carb. Just apply enough pressure to hold the drill but not enough to damage the barrel. You have to hold it like this for the remaining adjustment, a 1/16 gap barrel to carb throat.

Install one end of the piece of fuel tubing over the carbs fuel spigot. You should be able to blow through the tubing and carb.

Turn the low speed needle in until no air passes through then back out until you can just detect air passing. You now have rough set your low speed needle.

Start and tune your engine as when new or you first got it. Set high end first then adjust low end for best idle and transition. Low end adjustments should be no more than the thickness of a screwdriver blade at a time. Rev the motor up to clear any residual fuel in the crankcase. Give the engine time to normalize then back down to an idle then check transition. Its wise to check and reset the high end if necessary every few times you change the low end settings.

Dennis

the Wasp

My Feedback: (1)

aspeed

both new bearings are stock OS replacement parts, same numbers and same brands as the original bearings, the front bearing had only one shield, , the rear didn't have any,

all I can say is that after 7 gallons of fuel, the original bearing didn't leak like the new one does with only 2&1/2 tanks of fuel threw it on the bench !

Jim

1QwkSport2.5r

It's nothing new that some OS bearings are substandard quality. Perhaps that is your problem. If you want to use high quality precision bearings, use Swiss made WIB bearings. They are superb. Leaps and bounds above anything OS uses.

the Wasp

My Feedback: (1)

thanks for the tip, I will check out their prices


as for the OS bearings, the front one is a NTN (made in Japan), the rear is a different brand, a very well known brand, but I can't remember the name

Jim

jaka

Hi!
Yeah!
WIB bearings are the best! Always used them in my pylon racing engines.
But back to the carb! You said that your 10cc OS engine did stumble when you gave full power.
How did it stumble? Did it "bludder and sputter" (too rich low speed needle) or did it hesitate ...(too lean low speed needle).
What fuel did you use? 5-10% nitro is all it takes to have all engines run perfectly.
What glow plug? OS 8 or Enya 3 are good plugs for most sport two stroke engines.

the Wasp

My Feedback: (1)

Plugs) I used both the OS #8 and the OS #7

on the first start after I replaced the bearings I could tell it was lean in the mid range so I richen the idle screw a lot, then it would burble as I advance the throttle, so I would lean it 1/8 turn at a time, it would get better every time I adjusted it, but then it came to a point it became too lean and it would cut out, I could not find the sweet spot,,

I tell you one thing that I will recommend to every one, I am done, done, done with using 3 Tubes on my fuel tanks, from now on on all my planes I am going to do what I do on my Helis, I am only going to use 2 Tubes going into my planes Fuel Tank, 1 for Pressure from the Muffler, and 1 with a T-Fitting for Fuel to the Carb and Tank Filler,,, this will elemental 1/3 of the problem I could have with my Fuel Tank Lines

Jim

1QwkSport2.5r

I've found 3-line tanks (Uniflow) do not work well in R/C applications. Coming off the throttle would always load the muffler with fuel through the pressure line. Engine size didn't make any difference - a .25 would do the same thing as a .90. I could get a perfect idle and perfect top end, but the midrange would always be blubbery rich. Much the same sort of behavior that I experienced using a Perry pump. Switching back to a standard 2-line fuel tank (clunk line and vent line to the top of the tank) gave a predictable engine again.

jrf

My Feedback: (551)

Sounds like you are eliminating the pressure line. That is not what the Wasp is saying. He is eliminating the fill line and filling it through the pressure line. Modern glow engines are designed to run with fuel pressure. That is provided by the pressure fitting on the muffler or by a pump. (Not both.) Some of them can't even be made to go rich on the top end without fuel pressure. Fuel pressure prevents the engine from starving when you pull the nose up, or if the tank is not mounted on the centerline of the carb. Maybe you are trying to set the idle (or top end) too rich? Is your engine older and designed to run without pressure?

1QwkSport2.5r

I use muffler pressure on most engines. The vent line is connected to the muffler, feed line to the carb. I fill through the feed line. The 3-line setup I used had a clunk on the feed, a clunk on the pressure line (on the bottom of tank near the feed clunk), and third for filling. This setup made the engine run unpredictable. Midrange was always rich and couldn't be adjusted out. Venting to the top of the tank as is typical and using muffler pressure to the vent made all the difference.

the Wasp

My Feedback: (1)

yes, fill the tank using the feed line to the Carb

and use one of these Clamps with a T-fitting that I use on my helis

so I will have only 2 hoses going into the tank

Jim

Mr Cox

There is no problem using three lines to the tank, the question is what you do with them. If you have two ending at at the top of the tank, one can be used for muffler pressure and the second for filling (plugged during flight). That way one doesn't have to remove the line to the carb for filling, and the pressure line is never touched either.

1QwkSport2.5r

While I do agree, I see no issue with either method. i should have been more clear - a clunk on the exhaust/vent line is ill advised on an R/C engine. The Uniflow works very well on fixed throttle engines however.

hsukaria

If you suspect that the front bearing is bad, I would replace that first before doing anything with the carb or remote needle. Your problem might be the crankcase leak through the bad bearing and your tuning problem might go away after replacing the new bearing.