CGRetired

My Feedback: (1)

I have a Super Tigre 75 (new generation). So far this year, I have gone through about 5 glow plugs. My OS engines and the Evolution does not go through plugs like that.

What am I doing wrong with the Super Tigre 75? Yesterday, for instance, I got to the field and put the plane to gether (Tiger 60). My first attempt to start... well, it would not start at all. I tried two glow-drivers, no engine start. So, I swapped glow plugs with my last spare. It started right up. That was the 5th glow plug for this year. Most of them are OS plugs. (One was the original whatever what was in the Super Tigre when I got it new). Obviously, it ran just fine the last time out, which was about three or four days earlier.

What am I dong wrong? To lean? What?

DS.

krossk

My Feedback: (27)

Take a look at the element in the dead plug. If the coil is deformed and/or pulled up inside the shell, then it is definitely too lean. Regardless, I'd start by richening it up and re-tuning it. Check everything out for air leaks - carb base gasket, fuel lines, etc. Also, are you running it out of fuel in the air, or landing still under power? It's possible that running out of fuel may be causing a lean condition that is killing the plug. Or that engine may just not like the plugs you are using - try a different brand or heat range.
Good luck and let us know what you find.

Kaos Rulz

I agree that you might be too lean. I have two ST 75's and I run a Fox idle bar plug in one, and an Enya #4 in the other. Of the two, I like the Enya. If the Fox will ever go bad, it'll be replaced with an Enya #4 as well.

HighPlains

My Feedback: (1)

If you haven't been too lean, I would check the bearings. If they have a small amount of spalling, the particles of metal will kill the plug. You should be able to detect this by removing the plug, oiling the engine and slowly turning it over while feeling for any rough spots. Do this also while pulling forward on the crankshaft.. You can also open up the back cover and inspect the rear bearing.

CGRetired

My Feedback: (1)

The engine was new last February. Probably has, oh, maybe 75 flights on it.

It may be the issue of being to lean. I will h ave to get more involved in this to figure out what's going on. I am out of glow plugs and have to make a visit to the LHS!!

DS.

N1EDM

My Feedback: (2)

Let me throw another possible hook into this... how is the tank?

I had a similar problem with an Irvine .46. My problem was that I had rebuilt a plane to use the engine, and I used an old tank. I thought I had cleaned it up OK. The tank was several years old and still had the old plumbing in it.

My theory is that the tank wasn't as 'completely clean' as I had thought, and there was something left behind by the corroding tubing, fuel line and clunk. What I had was a classic case of contamination in the fuel - from a not-so-clean tank. I kept blowing plug after plug. I might get a flight out of it, but that was it..... until I changed my tank to a completely new, clean system.

It's just a thought.. you may have a completely new tank...

Bob

ICE_MAN

I haven't had to change the plug in my St G2300 yet! 14+ gallons!

My bet is that your engine doesn't like the plug/fuel/prop combo..

What fuel are you running? What Plug/ Bet you can guess i'm going to ask about the prop next

If your over loading your engine it will do this.. My bet is that you've already got her tuned for a smoke trail in the air.. Which shouldn't be to lean to cause this type of behavior..

Also some plugs don't like certain types of fuel.. I tried to run Wildcat 15% in my 1.40 and it wouldn't run worth crap! No matter how I tuned it! Switched bak to COOLPOWER 15% and the problems went right away!

The fuel being old/contaminated is also a very good possibility!

Regards, Cody

CGRetired

My Feedback: (1)

Cody and Bob:

Here goes... Ok.. Bob first. (I used to live in Taunton.. that was 1970 - 75 when I joined the Coast Guard. Are you Navy? See the P-3 moniker). You may have hit on at least part of the problem. The tank I have is the original but the plane, a Goldberg Tiger 60, is not yet a year old. I did have a failed fuel tube inside the tank, it just plain disintegrated at the metal tubing that goes through the bung. I replaced it (the tubing) and all seemed well until Sunday. I did buy a 2 ounce larger tank to put in that plane mainly because it would routinely run out of fuel in right at 10 min 30 seconds +/- 30 seconds. So, when the timer hits 10 minutes, I'm on glide path to landing, going around for a missed approach is risky business!! haha..

Cody: I used OS F plugs, and S&W 15% Hi-Rev fuel. I had been using S&W 15% standard fuel but the High-Rev was recommended. It uses a different oil type (not content.. still 20% oil). My other planes love it (the Hi-Rev).

Something I failed to mention in the original post was I also changed exhaust systems. I guess it just slipped my mind at the time. What I had was the Super Tigre 75 muffler just fell apart in the inside (baffle came un-done, muffler is sealed, does not come apart). I ordered a replacement, got same results after about three tanks of fuel. So, I opted to go to a tuned muffler and header system. The plug issue was basically the same with the old muffler, so I don't know if I attribute it to the new system.... YET!!

One issue that I had on Sunday was that the engine would not run for longer than about 10 seconds no matter what I did with the needle valve. It seemed to run out of fuel. I added a 3 inch extension to the header in order to improve the tune point (as recommended by the club pro's) after it had been flying just fine but not peaked as yet.

I removed the extension and still had the problem. I thought I had it fixed at one point, but when climbing vertical, it ran out of fuel. Obviously lousy muffler pressure to the tank. Soooo... what I am leading to, and as you have suggested is that it MAY be running on the border-line lean. I need to move the fuel pressure line to a different location (recommended by the pro's again) to the center (just forward of the first baffle in the muffler section).

One thing, though, I gotta head to the LHS and get more plugs..[]

Thanks, guys, for the input.

DS.

RCKen

My Feedback: (9)

CGretired. Ok, it does sound like a glow plug problem you have. It's odd for OS plugs to go out that quick. A couple of questions that come to mind that you didn't mention. So you use after-run oil? Do you put Armor-all (some use it to cut down on foaming of the fuel), or anything else, in your fuel. Sometimes these things can coat the coil on the glow plug and cause it to burn out.

Ken

ICE_MAN

Awh the tuned exhaust might hold the key to your problem here!

Did you richen both needles up and retune it for the new exhaust? If not you could easily still be running it way to lean and get pretty high RPM number which would cause this plug failure!

Also, you say it's "running out of fuel" Try putting a check valve in the muffler line between the muffler and tank.. At one point in time I had a similar problem with my 1.40...

Also your tank: Does the clunk in your tank have a filter? If so remove it... Those things have caused me so many headaches[:@]
Just put and in-line fuel filter between the tank and carb... As a side benefit of the in-line filter it will hold extra fuel.. So if you think your engine is "running out of fuel" a combonation of the check valve and in-line fuel filter shoould help...

N1EDM

My Feedback: (2)

Hi CGReteired,
I'm still betting on comtamination from the tank parts that fell apart. That was identical to what had happened to me. There was some kind of contaminant still floating around in the tank, clinging to the inside wall, etc., that would get into the engine and foul/burn out the plug... These other guys have good ideas too, but I'm betting I was right.

As for the P-3, yup, spent 27 years in the navy and USNR (wish it had all been active duty now). Spent the first 8 years in radio, then the next 20 flying as an acoustic sensor operator in P-3's out of 'South Weymouth Prep'. Had 2500 hours. If you go into the old hangar spaces, you can still see my fingernail marks on the doorframes from when they made me retire.

Us swabbies gotta stick together. Hope everything smooths out with your plane.

Bob

CGRetired

My Feedback: (1)

Wow... Ok.. one at a time.

Ken: I do use after run oil, but I use Mobile 1 and do NOT use Armor-all at all. Never thought of that, but, nope, I don't. But, thanks for the hints.. and for things NOT to do!!!

Cody: You may have a point there. I never adjusted any needles except the high-speed needle. I pinched the fuel line at full throttle looking for a slight rise in RPM. Got that so i thought I was ok. Perhaps not. Both you and Bob have come up with something that may be an issue. I bought a new 14 ounce tank. Perhaps this is the time to install that and follow your instuctions for fuel filters and the good old clunk. BTW, Cody, what do you use for a clunk if not one with a filter? Just a weighted one, I imagine.

Ok.. tomorrow is a fly day. Supposed to be hot hot hot, but I will swap out the tank first thing then head for Strawberry Field (our flying site).

Bob.. I did four years on Sub's in my first hitch, Holyloch Scotland with Nuke FBM Subs. After that, I got out and did 7 years on the economy.. got laid off from Ma Bell (Brockton /Framingham Toll Test) then headed to the Coast Guard. Found a home. Eventually did 26.5 years, retired as CWO-4. Great stuff!!! Really enjoyed it. Now, work as a test engineer for the FAA and Air Traffic Control Secondary Surveillance Radar systems (those gizmo's that interrogate the transponders on all A/C).

Aaaaaanyway, got back into RC a few years ago and am truly hooked! As I said... good stuff!!!

Thanks all for the help. I will be trying all hints tomorrow. Will report on my results.

DS.

hhhhhhhhh

it could even b 2 rich and givin the glow plug 2 much fuel 2 handle[&:]