acdii

OK, I will need to find the manual, all I got was the motor. When breaking in the magnums, they run for 10 minutes, cool for 10, run for 10 and so on for a total run time of 40 minutes with minute tweaking of the needle. Both the 52 and 91 that I have ran great afterwards, both start on the first backflip of the prop once primed. Neither had idle or throttle up problems, and need very little needle adjustments for weather changes. In fact they both out perform my OS 52 which will only start using a starter motor.

Does the FOX Miracle plug work in these? Its what I have on hand that I use in all my 4 strokes without problems. From what I was told from the guy selling it, it has 11 minutes on it, looks it too, just a few brown spots on the muffler, but the valves are clean and it has fresh oil on it. It turns smoothly, has good compression, and doesnt have that click clack the Magnums do for the pushrods.

blw

My Feedback: (3)

This one took over 2 gallons to get over break in issues. I can't remember how much more I've run on it. It was turning an APC 15x6 in the low 9k. W8YE thinks it will break in more and turn a 16 after maybe 3 gallons. It will turn the 90 size pattern kit it's on into a missile.

SrTelemaster150

I just set up johnboy's engine W/CDI. On GI a 16X8 would cause the engine to detonate & backfire after a short WOT run @ 7700 RPM. Way too much prop. All I had in a 15 was a 15X5 & that was too little turning 9700 on GI, 10000 RPM on CDI. Idle was 1800 on CDI. Midrange was a bit rich when the LSN was tuned W/CDI for best dile & transition but it would run smoothly @ any RPM when the throttle was opened then reduced. Not sure if a bigger prop would help or maybe a velocity stack.

I think a 15X8 would be ideal for this engine W/CDI.

Hobbsy

My Feedback: (102)

AC, the Fox Miracle will be perfect, using them for 20+ years I can say they work very well.

acdii

Great I have a half dozen of them on hand so I should be set for a long time. I have 5 glow and 2 gas engines, and plenty of plugs for both. This Saito is so pretty that it will be a shame to hide it behind a cowl, so I need to find just the right kind of plane to install it on. The head would look nice poking out of the white cowl of the Chipmunk, but I already have a magnum 91 installed in it and all setup.

blw

My Feedback: (3)

acdii is member #815

Dan, a lot of people consider the Saito velocity stack as being restrictive on the 125 even though it fits fine.

Jim Branaum

My Feedback: (3)

QFT!

If you tune properly the Fox Miracle is a great plug for a Saito. If you really don't want to tune properly, spend lots more money and buy one of the plugs touted by the in crowd. But rest assured there are many who will wax your speeds and starts with a Saito and a Fox Miracle plug. The hardest thing to remember is that they DO fail! Once every other year or so I get bit by one failing and it takes me the better part of a tank or more so of fuel to realize I have a glow plug problem and not a tuning problem. Then I replace the plug and retune and forget about it for a very long time. I have a Saito .56 that I don't recall the last time it got a new plug.

acdii

I have yet had to replace a GP on my 4 strokes, but have had to replace a plug on my DLE. The OS type F plugs are currently in my OS 52 and Magnum 91, I still have one OS F and 6 Fox plugs in my kit, so well prepared in case a plug does foul. I use the GP starter that has the meter in it so I can tell if the coil is going south by the amp draw. After a while you get to know exactly where each engine is on that little meter. I am just PO at it because the plastic threads broke off so I have it taped down with electrical tape so it still works. Hobbico has ignored my support requests on it. All I want is a replacement cap for it.

SrTelemaster150

It is slightly smaller than the venturi, but the spray bar would impart some restriction in the venturi so I think it still might be worth a shot.

I wish I had remembered that I a had one on my FA91S before I packaged the engine up for return shipment. W/the electronic digital tach I could have accessed any gain/loss.

RC_Fanatic

My Feedback: (1)

Adding the velocity stack to my 100 sure cut down on the mess. I did not notice any decrease in rpm but it seemed to use less fuel.

SrTelemaster150

Absolutely! The "V" stack allows the engine to pull in the fuel spray that would otherwise be lost @ low/midrange RPM. It allows for a leaner LSN setting.

blw

My Feedback: (3)

I used one on the 125 too. I think it was Hobbsy and others who tached with and without, and without measured better.

frets24

My Feedback: (15)

Definitley a loss of RPM on the 125 with a stack. Not terrible though; Mine loses about 275-350 with it. Still use it in the application my 125 is in because it helps keep the inside of the cowl cleaner and the 125 is a bit of overkill in the plane as well so I can afford the loss.

Both of my FA62's have stacks and the max rpm is the same with or without. It seems the larger the engine the more sensitive to small restrictions to the intake airflow.

By the way, blw; You'll know that you're really in the sweet spot and fully broken in when you can raise that 15x6 to a 15x8 or a 16x6 and still break 9k And it will certainly turn a lot of planes into missles! It will really haul my 72'' 14lbs KI-61 Tony around the pattern like a cat with it's tail on fire! GREAT engine!

blw

My Feedback: (3)

I put stacks on my smaller Saitos. One of them made a dripping mess without it.

I had to stop flying for a while and the 125 sat for a few years. In the meantime, I found more damage to the model from an earlier flutter incident and did major repairs. I'm almost finished putting it back together again for flying. You said it just right: finding that sweet spot.

hsukaria

When you guys mention fuel dripping or splashing out of the carb, is that when the engine is mounted upright? My 4-strokes are all mounted inverted, so I don't know if I should be seeing this.

Hobbsy

My Feedback: (102)

The reversion occurs whether the engine is upright or inverted, it is caused by the air and fuel mixture flowing inward at a high velocity and then bouncing back when the intake valve suddenly closes. Being a tinkerer I just modified/ re-modified my old FA .40, home made velocity stack by shortening it.

The reason the 1.25's performance is reduced using a Velocity stack is the ID of the stack is slightly smaller than the 1.25's venturi.

FNQFLYER

Ok, I am back, just been playing with some P3C's. Now on Bolly props, there are 2 versions, the clubman, (a pretty baby poo yellowy thing) and the serious propeller which is made from carbon fibre lay ups. The difference between the 2 is like chalk and cheese. For reference the ones (Bolly) I have seen here are clubmans. Now on the matter of the 35 two stroke. That era engine would equate to a Saito 30 (over powered) or a modern 25 two stroke. I use the old 35's (OS mostly) for Old Timer comps. For reference, OS makes a 32, Supre Tigre makes a 34 and ASP also used to make a 32 all considerably more powerful than the old 35.
Old Fart that Rainbow would benefit from an OS 32 in front, it fits inside the cowl and is "ideal" for th "average" sports flyer, try it. I would recommend the OS 32sxh with a Nelson muffler or alternately a Tigre Paw as a good combo. Enough about 2 strokes, .

the pope

Before we head on back to 4 strokes i have a 34 supertiger and its a great little engine . It moves my airbourne 25-40 scratch built uglystik like nobodies business . Now back to business ! Cheers the pope

Jim Branaum

My Feedback: (3)

Hmm...

I wonder what I pay for having a stack on my 150. Well, never mind. I use the stack as the support for a chunk of my wife's hose to keep the dirt out so any measurement might be meaningless.

Hobbsy

My Feedback: (102)

Jim, the stack on the 1.50 is much larger and longer the the .50 to 1.00 sized stack. It does not reduce performance.

SrTelemaster150

Actually the 150/180/220 big bore carbs have "V" stacks sized for each carburetor venturi. They are not "one size fits all like the FA50 series "V" stack.

I would say that they enhance performance on the big blocks. At least as far as fuel economy goes.

Jim Branaum

My Feedback: (3)

Thanks! That makes my filter support worth having... - - oh, she already is...

Rudolph Hart

Very funny jim
I filter my fuel when refueling but don't run an inline filter after i saw how much sand gets sucked into the carby when i taxi out to the strip on a sand surface covered with a thin layer of grass.I'm not gunna whimp out and carry it down there like some precious poodle.And besides,if i ran a stocking filter the engine would be way rich by takeoff time.Call me stubborn and stupid.

On a more serious note re v stacks as you call them..i always get a better ground and inflight tune with them,specially as regards throttle response and overall smoothness.Cheers boys.

Jim Branaum

My Feedback: (3)

Oh, I thought you knew! I know where the rocks are.

OOPS! Airplane engines.

Your observation was a problem when I was forced (I guess invited is a better word ) to fly in high dust/sand environments. The solution I used was to take the handle of my drill press (ball shaped on a lever) and use it for the form of a piece of wire screen I then slide over the stack and IT holds the stocking in place with enough surface area to work well and tuning becomes fairly standardized. The stocking gets dirty in one area, but the air goes in elsewhere. If you are like me and too lazy to change the stockings, a light spray will knock most of the EXTERNAL dirt off. As for the throttle response issue that may be true but at what final cost....

Hobbsy

My Feedback: (102)

Barry, Dan posted on another network that the 1.25's venturi is 8.8mm in diameter, the stock V-stack is 7.75mm ID. Per pictures