modeltronics

My Feedback: (27)

I'm not sure I understand what you are saying, Do you think someone changed both the carb and the intake?

Do you have time to talk this afternoon?

Glowgeek

Pete, I sent the 120 Fathead manual to your email. It's written in Jap-english so good luck with it.

I have overhauled two fathead 120's in the past but did not find it necessary to adjust the midrange so can't help with that. I have another on my bench that's slated for gas conversion but have no time to play with toys at present.

Jesse Open

Just wondering out loud. Those carbs are a real quality item. They contribute to an outstanding idle especially with the milder cammed and reduced compression versions.

Yep, we can try 20 meters.

Glowgeek

So, reading through the 120 fathead manual a few times it appears that the midrange adjustment is to be performed after the break in period and is used to set the proper fuel mixture for transition from half throttle to wot. All this with the HSN set 3 turns open and the airbleed orifice fully closed. Once midrange transition is set the airbleed can be fine tuned for stable idle and the HSN set for flight. That's what I get from reading it anyway.

I posted the manual here if others would like to review it.

Jesse Open

That is pretty much it. Being able to trim the midrange improves idle as well. Idle adjustments with the late carb often require compromise to eliminate drop dead transitions.

Glowgeek

Absolutely, and the level of compromise with the later 2 needle carbs can differ greatly with engine health, fuel type, level of break in and even from one displacement to another. That superb fathead carb allows for compensation of all the above. A wonderful carb.

I've not found a need to dial the midrange disc, plus or minus from the factory setting, but my two fatheads were well broke in and in excellent health after cleanup and new bearings. I did play with the midrange dial on my first one but put it back to factory reference marks as it ran best there. Sold those two.

My third fathead is on the bench awaiting clean up and bearings. It will get CDI and hopefully run smoothly on gas with the factory glow carb. My hope is that the midrange adjustment will provide sufficient leaning to keep the engine from going super rich just above idle without using a fueling solenoid; a common problem when running gas through a glow carb. If not, I will install the DIY programmable fueling solenoid system I've been running on my other gas conversions. All of those DIY conversions are running gas through the factory glow carb and run great on the ground. Yes, on the ground. When I am able to get away and fly again those gas conversions will be the first to take to the air.

I have many glow powered planes to fly as well, always will, so no gas bashing please.

Jesse Open

Lonnie,

The early carbs were super devices. The fact that a couple ran fine at "factory setting" is all the better. They provide many tuning options that can really improve operation at the idle and mid ranges , beyond the limitations of the later version.


Gassers off limits?

Nice try, Open discussion. I will continue discuss gasoline versus glow in any and every manner I choose.(Within forum rules)

When I don't agree, you will know it.

Jim Branaum

My Feedback: (3)

I need a bit of help/guidance.
I have a friend who got himself a partially disassembled 115. I had a 91 sitting around with a bad carb issue so we scavenged the valve covers (direct fit), the back plate (needs to be sanded down a few thousandths as the crank/rod pin scrape on it - and or add a gasket) but when we went to put the carb updraft tube on, it was a bit too short. Any ideas where we can get the right one? Someone got a trashed engine?

Speaking of trashed engines, I have a 65 that has a bent carb updraft tube. I am going to try to see if I can tap it out a bit, but if anyone has a trashed 65 around I am also interested. Running a 76 inch Cub on a 56 right now and have dreams of putting the 65 to work there.

the Wasp

My Feedback: (1)

Saito should be proud.

Glowgeek

Saito intake manifold for the FA-115 is sai11569, for the FA-65 it's sai6569. Both part numbers are discontinued items but you may find one somewhere online. Swap meets are an excellent source for cheap donor engines.

Jesse Open

Can you post a pic of the injured intake tube from your FA-65? I can probably set you up with a fairly simple and effective fix.

1200SportsterRider

What a ride this would have been for a Saito 90 TS. An EZ- Global Cessna 182

Glowgeek

That's the same model a fellow club member is assembling. It's his first attempt at putting together an ARF so I've been helping him along. Some assembly required is an understatement if there ever was one. The manual is terrible, relying on many very poorly taken photos and poor printing. It is a well built model, should fly nice. His choice of power plants is an Evolution 61NX 2 stroke. Oh well.

Jim Branaum

My Feedback: (3)

Jesse Open

That does not really look bad enough to impair operation. However, if you really want to remove most of it.....

Measure the tube ID and pick up a few steel bearing balls that fit with about .010" to .015" clearance. Drop the bearings into the lightly greased tube until the last ball is just below the tubes end. Using a flat nosed punch, tap the balls thru. You can use a smaller ball or two for the first pass. A set of smaller balls may be helpful from the other end to clear the tube if you run into a stubborn drive.
A curved, wood block can be sawed and filed to back up the tbe while tapping the balls thru.

Try it, patience pays.

Jim Branaum

My Feedback: (3)

Thanks. I will try that.

FlyerInOKC

My Feedback: (6)

I got a pre Surpass FS-120 with a dent in the intake tube a lot worse and it has no affect on performance.

1200SportsterRider

Stinger/RCFG 10 cc 2 stroke gasoline engine

Several weeks ago I posted that I had purchased this 10cc Stinger engine. It had really soft/mushy compression, I put 10 oz of fuel through it, 90 octane ethanol free/ 40% lube through it. The compression didn't improve at all. I ordered an RMJ piston ring and voila, instant, snappy, finger chasing compression. Lonnie said it takes two gallons of fuel to run the stock ring in. That could take years at the rate this thing doesn't burn fuel. When we get a little warmer day I'll fire it up.

Jesse Open

Yep, had a few minor dented intake tubes on Saito engines and found no detriment aside from ugly.

FlyerInOKC

My Feedback: (6)

The black Saito in the background is a lot prettier!

Jesse Open

Black Saitos are handsome indeed. At least as long as they are free of scrapes and scratches.

Japanese engine (Vintage Saito FA-65) but the ring is a Gavis ring made in Great Britain. Break in is easier than OEM ring and the durabilty is excellent.

1200SportsterRider

That 150-S is an early 150 with the 11.24 to 1 compression ratio, I installed a new RMJ ring and Boca Bearings but haven't run it. I think I got it from Crunch.

Jesse Open

The black FA-65 was built from parts. A new old stock case was gloss black epoxy powder coated. Fitted with a dual plugged cylinder from an FA-325. The piston is a new old stock high compression FA-65 pillow top piston and Gavis ring. Exhaust is totally home made, including the metric hex nut. The bell mouth, true radius intake stack is made from aluminum bar stock Carb is also fitted with a flanged, brass guide bushing at the low speed to ease idle mixture adjustment.

Never had a chance to run that one. A good friend, here on RCU needed the rare cylinder so it was handed off to him. The piston and Gavis ring are now in my favorite FA-65. Runs great and will be getting a CDI con-version this spring.
The improved timing control will help the engine make the most from its raised compression as well as the methanol fuel.

FlyerInOKC

My Feedback: (6)

I'll bet she would have ran fantastic too!

Jesse Open

Dave's FA-150 should get a "special" plane. A very nice engine that one.

Followed me home from breakfast this morning. New in box, oversized and overweight. Made in Austria a few decades ago. What to do???