Hey Guys

I need alittle help with a Saito 65. I have several Saitos and have had no problems with them till this one came along. I have had it on 2 different planes with different fuel tanks and tubing. What it is doing is quiting in flight at wide open throttle, It idles fine and the transition from idle is fine. After I dead stick it in I can richen it up by a few clicks then it runs fine for alittle while then quits again. I richen it up more and it runs fine for awhile again. I keep doing this till it is so rich it falles off and I have to go back lean again. Which by now is around 3 turns then it starts all over again. It seems like the High neddle donst make as much difference as it should. I just got it back from Horizon Hobby where they said it was fine. Running 15% nitro have tried up to 30% and an OS-F glow plug still no luck. I few 5 times today and 5 dead sticks.

Thanks for any help you can give me.

Well, make sure the needle valve is not moving during flight due to vibration... That could be the problem-

Measure your "turns out" before and after a dead-stick and see if it is moving---

If the high end NV adjustments are not having the effect they should have, I would guess you have crud trapped in the spraybar or a air leak somewhere. Maybe air leaking around the needle or in the fuel line or tank. Do you see bubbles in the line when running at full throttle? If not, remove the HS needle and backflush the spraybar with fuel.
I have a older saito .65 and it is a very smooth running engine that rarely ever dies in flight.

Ibautoman:

With a Saito FA-65you could have either one of two carbs. The older engines came with an air bleed type, the later ones have a two needle type.

If you have the air bleed type, be very sure your throttle linkage does not pull the lever away from the carb. There is a flow regulator valve inside, the throttle barrel is the moving part and it has to be firm against the inside end of the bore. Also check the small wire spring clip on the lever end, you should see its two arms pressing the barrel in. If the barrel is not kept tight you will have good top end, but many problems trying to slow the engine. You will have the same result if the linkage pulls out on the lever.

If yours is the later two needle carb you probably have the low speed adjustment set too lean. The LS adjustment has a strong effect up to about 3/4 throttle. When everything else is fine, tank height, no leaks, good fuel and plug, etc, most Saito running problems are a lean adjustment on the LS. The engine will run fine with it rich, but lean can be a real pain.

Hope this helps.

Bill.

Hey Guys

Thanks for all of the responses. I belive I have the newer engine. I will check that HS needle valve and spray bar. Also the LS is in a good ways. I have heard it should be flush with the throttle linkage. I will richen it up and fly Friday to see if it works better.
Thanks again
Jim

Pictures:

First is the lever end of the air bleed carb, showing one of the two ends of the clip holding the barrel tightly into the carb.

Second is the older TN with the metal throttle lever, starting point of the LS adjuster is flush with the surface of the needle.

Third is the later TN with the plastic lever. Starting point for the LS is about 1/32 below the surface.

This starting point on the TN carbs will be too rich for normal running, but it will run at full speed and idle, usually it will stumble on transition until it's leaned from that point.

Peak the HS, then check transition, leaning the LS a little at a time until it comes off idle well, then go a little more and recheck. You will start getting good transition while it's still rich, you can leave it there if you wish but the fuel burn rate will be high. Keep going lean until it doesn
t come on throttle crisply, then go back rich until it does.

All the time you're doing this keep rechecking the HS setting, the two will interact. After the LS is set, then go back to the HS and richen it to get your 200-300 rpm rich setting on the top end.

Bill.

I have seen the same problem at our field. We determined the bearings are worn and the engine is over heating. If the bearings have just the slightest wear, ea. feel just the slightest rough or slightest play, they are causing friction witch causes heat and over heating you see the picture. richening the needle valve covers the the problem a little more fuel/oil through the bearing but as you know it doesn't work for long. The best way to check your bearings is to check them hot. Just after the engine is run rock them back and forth feel for the slightest roughness and hold your prop tips and rock to check for play. there should not be any. Just my 2 cents worth. I install bearings for the guys at our field.

Bruce

Thanks again for the replies.

Bill It looks like my engine is the middle one with the metal throttle arm. I will start the LS out flush and go from there. Adjusting like you recommended. Sounds like you have had alot of experience with Saitos. Which is good for those of us that need help, I know when they are right they run great. I have a Saito 100 on a 4-star-60 and it runs great. But it took me alittle bit to get her dialed in.

Bruce, I also thought about the bearing But I sent it in to HH and they went over the whole engine and replaced both bearing and the push rod tube seals. They charged me $78 bucks to fix her but it wasnt any better than before. They sent a note saying it was running fine but it was not. Thanks for the thought.


Thanks

Jim

Jim:

Another thing you might check is the o-rings on the intake pipe. The mid block Saitos tend to have a leakage problem at the head end, it would not be a bad thing to replace it.

Bill.

Hey Guys

A update on the Saito 65. Had a good day today as far as the weather goes, So I got out to the field. I tried the LS out flush and then adjuster the HS and still ran about 45 seconds to a Min and quit. So I replace both o-rings on the intake and it ran alot better. But I am still not there yet. It will run around 3-5 Mins before it quits now But it still quits everytime I fly. A friend had a perry pump and I tried that on it but it still quit so I dont think it is a fuel delivery problem. I still think I may have another air leak somewhere. I am not thinking to much of HH rebuild Because thoses o-rings needed replaced they sure wasnt new.

But I am still trying. Going to try again tomorrow if weather is nice.

Thanks
Jim

I had the same symptoms on a Saito .72. It ended up being the vent line inside the tank that was causing the problems. I used a bit of fuel tubing over the brass line in the tank as shown in the Dubro tank instructions. This was the first and last time I try that setup. Anyway, the section of fuel line was probably resting too firmly against the top of the tank and causing the tank to not feed without vent pressure from the muffler.