Saito shuts off
 

I know this probably seems like an easy fix, but so far it isn't. I have a Saito FA65 that I'm bench testing and it will run full throttle for a minute or 2 then shut off like there was a kill switch. Here's some obvious info to save time. New Glow plug OS F. there's fuel in the line when it shuts off, no bubbles or foam. Omega 15% fuel. It does it with a full tank, 1/2 empty and low. it doesn't matter what that condition is. Fuel filter is clean. Swinging a 13x6 prop at 10300 RPM. Glow plug looks great when pulled after the shutdown. Will easily restart after the shut down and do exactly the same thing again. It's running rich and not heating up. Idles great and great transition so low end appears to be ok.
Looking for advice from the experts! Thanks

RE: Saito shuts off
 

You're in the wrong forum. Go to "Engines". And running an engine at full throttle while on the bench is defintely a sure way to ruin an engine. Dan.

RE: Saito shuts off
 

You say its running rich. Are you seeing smoke from the muffler?
Most saitos will run and stay running by turning the high speed needle all the way in, then back it back out 3 1/2 turns.
At 10300 rpms.....your actually running a little high and sounds like you may actually have the motor too lean. This will definitely cause a motor to shutdown after a minute or so.
Most saitos ive got are running their best at 9000-9500 on the ground....some even slightly lower like 8500(the bigger ones).

This motor is new or used? If its used...did you set or check the tolerences/gap setting with the tools?

RE: Saito shuts off
 

First my apology for posting in the wrong area. Not good at this and will try to delete it.
The low speed screw is as recommended by the manual, counterclockwise until even with the hub. The high speed needle valve is out about 3.5 turns. Lots of smoke. Solid fuel draw. Valve tappets set at .003 - .004. I was surprised at the RPM also since a lot of my flying buddies can't even come that close with theirs using the same prop. Usually 9500 or lower.
It's a used motor.
So now a suggestion on how to delete this entry from this area and move it to the proper place and how to find it.

RE: Saito shuts off
 

Does the smoke out the tail pipe stay the same or reduce as the run progresses ? Also try running it at 3/4 throttle instead of full and see if the same thing happen. If it does try a 12x7 prop. How used is this engine, can you post a pic. Did you check for carbon build up.

RE: Saito shuts off
 

Visual looks the same on the smoke. A 12 x 7 is smaller than what I'm running on a 13 x 6, right? I know the first time I tried a 12 x 5 graupner full paddle and it went higher RPM than the 13 x 6. I have no idea of how used it is, bought it at a Hobby Expo a few years ago. there's hardly any carbon in the head or valve seat area. Really clean for what I think is it's age since Saito no loner makes it. So does the old rule of thumb for props work like this..... 12x5 would be 12 times 2 plus the pitch (5) = 29. 13x6 would then equal 32, so a tad slower RPM? If that's true, then the 12x7 would be 31, (less than the 13x6)? Also, I probably mis-spoke cause 3/4 to full throttle doesn't change RPM that much, I was probably at 3/4 or just a tad above. I don't know how to post a pic.

RE: Saito shuts off
 

Dunno why it's stopping, but I'd say both the High and the Low needles are too rich. Saitos moke very little smoke when tuned correctly. The low side is usually recessed in the arm and the high end is usually closer to 2.5 turns than 3.5 turns.

Maybe there's crap in your fuel and it's intermittently clogging the needle.

Copy your question and post it here:
http://www.rcuniverse.com/forum/m_33...m.htm#10090878

RE: Saito shuts off
 

double post

RE: Saito shuts off
 

Ok then try the smaller diameter prop 12x7 and see what happen. If you say there is hardly any carbon then it may just be that the engine is still not properly broken in yet. In that case be patient and run it at half throttle for another 16 oz and slowly work your way back up to full after the 16 oz. Another thing is to check all screws make sure they are all tight. Check carb for secure. Hope you are using good fuel with no water in it. Water in the fuel can also cause those symptoms.

RE: Saito shuts off
 

I'll try the different prop. Yeah, all god fuel and test stand tank is new. I use up fuel regularly, so it never gets a chance to sit plus it's the same fuel I ran this weekend in other engines at the field w/o a problem. I burn about a gallon pr month and properly sealed.
All good stuff! Ill give it a shot.

RE: Saito shuts off
 

My Dad had a Saito 45 that was new and did the same thing. It would run for a minute and just shut off. He changed the fuel, prop size and the carb. No difference. He brought it to me to see if i could figure it out. I asked him if he had tried another plug. He said the plug was new and therefore ok. I played with it for a while with no luck. I put in another new plug and it worked just fine after that.

RE: Saito shuts off
 

Warbird51 beat me to it!
As he says, try a new plug. I know you said it was a new plug already but even brand new items have faults on occasions (even Japanese products!) Anyhow - what do you have to lose!?!

Good luck, it'll be sweet as you like when you get it straightened out - you gotta love Saitos!

Cheers
Rick

RE: Saito shuts off
 

Try a new plug, but bad plugs tend to show symptoms sooner like not starting at all or start, run for a few seconds then shut off, you know hard starting no matter if rich or not. To me it sounds more like the engine needs more break in time.

RE: Saito shuts off
 

I've had a saito shutdown on me before while running at high rpm, over 10k, back when I was a newbie. I had the valves too tight. Engine just up and died. After several trial and error fix attempts, I adjusted the valves again to the low end of their range and ran the engine at a lower rpm. No more problems. You might give that a try. I tune and prop all my saitos for around 8500rpm to 9500rpm. Have a couple of 120s with well over 200 hours run time with only tear down and carbon cleaning done. Still all original parts. Just my opinion, but running them over 10krpm regularly is kind of hard on the engines for long term life.
Edwin