phatbob02

My Feedback: (126)

I bought a used saito 80 and I put it in my Hangar 9 Texan. The engine is mounted at a downward 45 degrees. When I tried to start it I would have fuel dripping out of the carb and flooding. After I cleared the fuel from the case I was able to start the engine with the plane inverted.

I flew the plane and about five or six minutes into the flight the RPM's dropped and I had to land. On the ground I noticed the engine was extremely hot. I decided that the smart thing to do would tune the engine on a test stand.

It took me two 12oz tanks of fuel to get her dialed in. I adjusted both the low and high end needles. I had 11,000 rpm with a 13x6 prop and a 1400rpm idle. A very smooth transition from idle to full, that's how it should run and I was happy with it.

For the last test I ran another 12oz tank at full throttle until it was dry. No rpm loss and no over heating. Back in the Texan!

I go to the field today and it's the same crap. I had to open the needle 3 full turns out to keep it running. On the test stand I was about 1 1/2 turns out. I check my tank because I couldn't figure out why it was going lean. Tonight I replaced the tank and I'm going to run it on the Texan with the cowl off.

Am I missing something? Is there something I should know about inverting Saitos. I've done it with other saitos and never had this problem.

How about tank center line to the carb? Any suggestions?

Thank for any help,
Bob

moto-x

If you can center the tank and carb lines,that would be ideal. Foam wrap your fuel tank to eliminate bubbles. If you are using a check valve in the muffler pressure line,pull it out and try it. I have seen this before and the muffler puts too much pressure in the tank and forces fuel in the carb. Impossible to tune like that.

Charley

My Feedback: (2)

I have a Saito .80 in a Cloud Dancer 60. Initially ran it inverted because it looked better that way. Never could get it to run consistently. The carb was about 3/4" below the tank CL. Couldn't move the tank - no room. Finally redrilled the firewall and remounted the engine sideways - cylinder at 9 o'clock viewed from the front - in order to get the carb on the tank CL. Runs well and very consistently now.

In my case, fuel was siphoning from the tank. however, you say you had to OPEN the (HS?) needle, suggesting a lean condition. Could something in your tank installation be pinching the fuel hoses? Can you take the hoses off the the engine and blow through the tank from vent line to carb line to check for free flow?

Be interesting to see how it runs with the new tank. Keep us posted; it's interesting.

CR

phatbob02

My Feedback: (126)

My plane would siphon and flood. I had to start it inverted.
My tank center was about 1" over the carb. I checked the tank and found nothing. I could have moved the tank some, but the center would still be over the carb. I decided to change to a bigger tank that I have that has an offset stopper. I cut some of the bulk head and re-drilled the fire wall. The tank fuel line is now flush with the carb fuel input, and the tank center is about 3/8" below.
I have everything remounted and I'm going to tune it on the plane. I don't know where to start but I'm going to go with the settings that I had on the test stand.

I'll post what happens.

Thanks for the input,
Bob

phatbob02

My Feedback: (126)

Well, moving the tank fixed the siphoning problem but the 80 still doesn't want to run at the 7:30 position. I did find out that Saito offers a Carb upgrade kit for the 80. I wonder what that means? Anyway, nobody has one in stock until late December.

As a last attempt, I'm going to put on a new carb from a 80 that I have NIB. If that fails the Texan is getting a O.S. 91 Surpass.

w8ye

My Feedback: (16)

The carb upgrade kits always worked great for me.

The have the spray bar and a HS needle valve and gaskets

phatbob02

My Feedback: (126)

I wonder if thats my problem and why saito sells it?

Thanks

w8ye

My Feedback: (16)

I feel that if the engine runs great on the test stand and terrible on your plane that there is something wrong about the fuel system on your plane?

chistech

Phatbob, I built a H9 Texan for my brother and we are running a 91 Surpass and it runs excellent with the stock tank location. It was a used motor we bought on ebay. We just put new bearings and adjusted the valves last night and flew it today. Running perfect again. I have a Saito 62 AAC in a Kyosho P40 that is inverted. It runs good but I thought it could run better. It was a new motor and I thought it was still breaking in. I was looking at a exploded drawing of the 62 GK and I noticed that it uses a velocity stack. I ordered one and installed it on my 62. It definetly helps as it now runs great. It is very finicky on the needle though and I only adjust it one click at a time and then make a complete flight. Some times it seems like it is running hot and too lean but if I richen it it runs worse. If I go in one click it will run better and doesn't flame out or anything. My needle setting is about 7/8s of one turn out. It does like muffler pressure and will not run without it in my plane. Does the 80 of yours have a velocity stack? If it doesn't it might be a good option if available. Just an idea.

Charley

My Feedback: (2)

Seems like there's an O-ring where the intake manifold enters the carb outlet. JIC, put some silicone cement into that joint. It once worked for me on an old Saito .45. Wouldn't hurt to remove the HS needle and force some fuel through the spraybar to flush it out.

CR

phatbob02

My Feedback: (126)

All good ideas! I'll try them all.

I know it's not the fuel/tank system. If anything it's better eliminating the siphoning.
I had the Texan at the field yesterday and the 3D boys were at a loss. They fly 82 Saitos inverted all the time and run 30% nitro.

I ran my 91Surpass last night on the stand and that's ready but I'll give the Saito another chance. I may install a saito 91 that I forgot I have. It's the same case dimensions.

I am thinking air leak and I didn't notice an O-ring in the head intake. I'll pull it again and check. I removed and cleaned the carb before all this started. I"ll also try the velocity stack. I may have one kicking around.

Thanks guys. I'll keep you posted,
Bob

phatbob02

My Feedback: (126)

There is an o-ring and a small washer on the head intake. I put a little Permatex Gasket between the two. I flushed the spray bar(again) and added a velocity stack that I robbed from my 91GK. I set the low end needle back to factory setting. I shortened my fuel line as much as possible.
It's mounted in the plane and I'll give it one last shot. after I mow.

Charley

My Feedback: (2)

Unless your engine is different from mine, there is also a O-ring in the top of the carb where the manifold plugs in. That's the one I was referring to. I glooped both ends.

CR

scratchonly

A while back, on hobbsy's advice I installed the upgrade carb kit and a home made velocity stack on my inverted 80. The adjustments were a bit touchy, but it worked fine. Are you sure your idle isn' too lean?

phatbob02

My Feedback: (126)

I ordered two of the upgrade kits but there on backorder from Horizon.
On the test stand the idle was on the rich side but the engine ran perfect. At this point I don't know where anything is.
I just finished trying running it again after all the advice and fixes. A bullet in the head is looking pretty sweet.[:@]
I pulled the fuel line and made sure the tank doesn't siphon. I set the idle screw back to almost flush and the high end needle out 3 turns. She fired right up but was rich as hell. It would only peak at 5800 with a 13/6 about 2 turn out. I gave the idle a half turn lean with no change. I went to half throttle and shes spitting and sputtering, then dies. It wouldn't restart and filled with fuel.
I'm at wits end. The only thing I haven't done is put a new carb on I have from a NIB 80. I'll try that tomorrow. Test stand first, then in the plane. If this fails it's an RCV 90.

LeeHop

Bob -
Was this most recent frustration in the plane or on the test stand?

phatbob02

My Feedback: (126)

Mounted in the plane.
Thanks

chistech

Bob, 2 turns out still sounds rich to me. None of my 4 strokes, OS or Saito run with the needle out that far. Most are around the 1 to 1.25 turns out. What happens if you try to go in with the needle?

DarZeelon

Quote:

ORIGINAL: phatbob02

It took me two 12 oz. tanks of fuel to get her dialed in. I adjusted both the low and high end needles. I had 11,000 RPM with a 13x6 prop and a 1,400 RPM idle.

Hey, Bob.


Are you sure about these numbers, or are they misprinted?

I would not expect any model four-stroke of this size, to idle reliably anywhere below 2,000 RPM...


Also, what prop is that 13x6? An APC would mean 1.46 HP, which is more than 9 of 10 .60'sh' glow engines tested by Dave Gierke in MAN 05/03.

The Saito .82A can only muster up 10,800 RPM on this size.

EDIT: Typo.

phatbob02

My Feedback: (126)

I had the high needle 1 1/4 to 1 1/2 turns out on the test stand and it did peak at 11k. I backed it off to 10,400 and let it run. The low end would idle at 1400 but quit after about 20 seconds. I figured that was fine and I'd adjust idle with my transmitter. All my other saito's idle between 2000 and 2400 reliably.

When I mounted it in the plane inverted, it was like starting over again.

I'm going to do the test stand once more and get it to where I had it. Then I'll but her back in the plane and try the pinch method on the fuel line to make sure it doesn't flood out.

I know the tank is ok now with relocating the center. I have a feeling it's something to do with the low end needle.

When I had it running on the test stand I had a good puff of smoke when I punched it, but no spitting or sputtering. The manual says that when it does that it's rich on the low end. I continued to adjust the low end until the smoke was minimal. The screw was in about 1/16" . Is this the norm. I've never been in that far on my other Saito's. Some I've never touched the idle needle.

phatbob02

My Feedback: (126)

It's one of the E Flight props I believe. 11,000 is what my tach said. As for it's accuracy, I'm not sure. It is about 15 years old and I'm just looking for peak.

The 80 is rated at 1.3HP. I think there are some that are rated higher and have a higher compression ratio. I don't even know which one I have.

I also read somewhere that the 80 can be a bear to tune.

DarZeelon

Quote:

ORIGINAL: phatbob02

It's one of the E Flight props I believe. 11,000 is what my tachometer said. As for it's accuracy, I'm not sure. It is about 15 years old and I'm just looking for peak.

Bob,


You are playing with fire!!!

Never run any prop designed for electric motors (with thin cuffs), on a four-stroke engine!

The power pulses produced by such an engine, will cause the blade roots to flex and to weaken, to the point of throwing the blades...


I don't think I need to tell you what can happen then...

proptop

My Feedback: (8)

Is it an "E-Flite" or an Evolution prop?
The Evolution line of props are designed for fuel burning engines...
The E-Flite props are for Electric ONLY and would definitely be dangerous on a glow engine!

phatbob02

My Feedback: (126)

OOPS, My bad!

It's an Evolution Prop. I have to work 3rd shift this week and my brain was still on first. All that I could remember was the big E stamped on the blade.[sm=red_smile.gif]

I thought I'd run the engine today but it's 62 degrees, blue sky's, and a 5mph wind. Not a good day for testing.

phatbob02

My Feedback: (126)

Guy's,
I borrowed a tach from my bud and re-ran the 80 on the test stand again. I have a 2600 rpm idle that stays running and it's peaking at 8600 rpm with a 13/6 prop.

At peak she rans for a minute and then the rpm's fluctuate. I noticed bubbles in the line. Can this cause the rpms to change and the engine to get hot when at full?

I've read somewhere that puting a filter in the line before the carb can reduce bubbles. Will this help?

Thanks