Fuel Injectors

[pete177]

I'm running an io-360-a1a and twice had to come down due to clogged fuel injectors. It seems that fuel sludge clogs the bleed air hole in the injector. I've seen it, just brown sludge. Now, I've noticed that when I pull the mixture out to stop the engine that fuel pressure remains high unless I relieve it by pushing the mixture back in to drain the fuel into the motor. I've always just pulled the mixture out and left it. I wonder if leaving it out allowed fuel to seep into the injectors slowly, then evaportate and form sludge. I wonder if it would help to get all the fuel out of the line at once while the motor was still hot so it would evaporate more quickly maybe. Just not sure and I'd like to keep it from happening after I get the new motor back. The motor starts to run real rough, typically right after take off, and wont make much power. Doesnt seem to show up during the 1700 rpm ground run. Any ideas?
Pete

 

[Tom-D]

This sounds like a contaminated fuel system.

 

[Maverick]

Pete, just out of curiosity, does the 177 after your name mean you fly a Cardinal?

Anyway, my Cardinal has an IO360-A1B6D and I've never seen anything like you are describing.

Jeannie

 

[poadeleted3]

I've never seen anything at all in my gas, except water a couple of times. I don't believe I'd fly a plane that had sludge in the fuel system... that's not supposed to be there, I don't think.

 

[Iceman]

How long is the plane stored between uses? week, month, year? I agree with the others and say it sounds like something is in your fuel system. If it was me I would totally drain the tanks and filter the fuel to see if you you can find any further evidence of this sludge. I would also follow the fuel system and make sure that everything is clean. I do not think the fuel can go bad so fast in the injectors if you use the plane on a regular basis. If I were you I would not push the mixture back in because that could be trouble if you have a ground problem on your mag switch (engine could start).

If you are going to spend the money to get you engine in tip top shape you might as well spend a little more to make sure it receives enough fuel.

 

[pete177]

Pete, just out of curiosity, does the 177 after your name mean you fly a Cardinal?

Anyway, my Cardinal has an IO360-A1B6D and I've never seen anything like you are describing.

Jeannie

Nope, its a Mooney M20E. If I was to own a Cessna though it'd be a cardinal RG. They are very pretty airplanes. What does it cruise at?
177 is the 177th fighter wing, New Jersey ANG. Fly f-16's out of Atlantic City. I was in that unit for 16 years.
It's only happend twice in the 230 hours and two years I've owned the plane. I dont think it's contaminated fuel. The holes get clogged by fuel varnish. Doesnt seem to be anything like fuel tank sealer. Anything in the tank should be caught by the fuel strainers I would think anyway. The mechanics are going to be sealing some leaks so maybe it wouldn't be a bad idea to get them to flush it somehow. As far as relieving the fuel pressure by pushing the mixture in, one wouldnt leave it in, ya push it in and then back out to dump the fuel out of the presurized line.
Trouble with overhauls is they may only cost 21k to get done but by the time you get finished with all the "we should probably replace this and probably service that" your up to like 30k and there's still more to do....sigh

 

[Henning]

I'm running an io-360-a1a and twice had to come down due to clogged fuel injectors. It seems that fuel sludge clogs the bleed air hole in the injector. I've seen it, just brown sludge. Now, I've noticed that when I pull the mixture out to stop the engine that fuel pressure remains high unless I relieve it by pushing the mixture back in to drain the fuel into the motor. I've always just pulled the mixture out and left it. I wonder if leaving it out allowed fuel to seep into the injectors slowly, then evaportate and form sludge. I wonder if it would help to get all the fuel out of the line at once while the motor was still hot so it would evaporate more quickly maybe. Just not sure and I'd like to keep it from happening after I get the new motor back. The motor starts to run real rough, typically right after take off, and wont make much power. Doesnt seem to show up during the 1700 rpm ground run. Any ideas?
Pete

You need to inspect your tanks and fuel lines very soon. This is a contamination problem, possible old fuel varnish or tank sealant... You haven't by chance ran auto gas or any fuel additives through it have you?

 

[Maverick]

Nope, its a Mooney M20E. If I was to own a Cessna though it'd be a cardinal RG. They are very pretty airplanes. What does it cruise at?
177 is the 177th fighter wing, New Jersey ANG. Fly f-16's out of Atlantic City. I was in that unit for 16 years.

The book says max cruise is 148 Knots but I've never seen that. Depending on altitude and air density I cruises anywhere between 130 and 140 knots at 24 inches and 2400 RPM. I have a three blade prop on my plane and it's my understanding that costs me speed. Reports from others seem to put the speed loss anywhere from 3 to 10 knots. My Cardinal had the three blade prop when I bought it so I have nothing to compare it to. The only other Cardinal I've flown was a 1969 FG with 180 hp and fixed pitch prop. That was also a very long time ago. Your Mooney probably gets better speed than the Cardinal.

In my rather biased opinion, the Cardinal is the prettiest single engine Cessna ever built. It makes the 172 and 182 look like somewhat blunt instruments.

You make me a little jealous in that you fly F16s. One of my greatest ambitions is to one day have the opportunity to fly a jet. I think the F16 is one of the prettiest fighters I've ever seen as well. I used to work for General Dynamics when they still owned that division but I worked for the Land Systems Division on the M1 tanks.

Jeannie

 

[pete177]

The book says max cruise is 148 Knots but I've never seen that. Depending on altitude and air density I cruises anywhere between 130 and 140 knots at 24 inches and 2400 RPM. I have a three blade prop on my plane and it's my understanding that costs me speed. Reports from others seem to put the speed loss anywhere from 3 to 10 knots. My Cardinal had the three blade prop when I bought it so I have nothing to compare it to. The only other Cardinal I've flown was a 1969 FG with 180 hp and fixed pitch prop. That was also a very long time ago. Your Mooney probably gets better speed than the Cardinal.

In my rather biased opinion, the Cardinal is the prettiest single engine Cessna ever built. It makes the 172 and 182 look like somewhat blunt instruments.

You make me a little jealous in that you fly F16s. One of my greatest ambitions is to one day have the opportunity to fly a jet. I think the F16 is one of the prettiest fighters I've ever seen as well. I used to work for General Dynamics when they still owned that division but I worked for the Land Systems Division on the M1 tanks.

Jeannie

Oh, no....I dont fly f-16's The vast majority of Air Force/ANG members are not pilots. Maybe 1 in 20 or 30. We're only forced to listen to the flippin' idiots They're very good pilots but unfortunately they dont know anything about anything else and its very hard to convince them of that. They usually have to completely screw things up before they'll listen to you to get them out of it
I get 147 knots at best power mixture at about 10,500 ft pulling 21/24. Funny thing is, I get the exact same numbers (actually 146 3/4kn) at 23/24 and about 8200 ft. I'm anxious to see what the new motor will do once it's broken in.
If your goal is to fly a jet you could probably finagle a ride in an L-29 or L39 without too much trouble.

 

[Iceman]

Oh, no....I dont fly f-16's The vast majority of Air Force/ANG members are not pilots. Maybe 1 in 20 or 30. We're only forced to listen to the flippin' idiots They're very good pilots but unfortunately they dont know anything about anything else and its very hard to convince them of that. They usually have to completely screw things up before they'll listen to you to get them out of it
I get 147 knots at best power mixture at about 10,500 ft pulling 21/24. Funny thing is, I get the exact same numbers (actually 146 3/4kn) at 23/24 and about 8200 ft. I'm anxious to see what the new motor will do once it's broken in.
If your goal is to fly a jet you could probably finagle a ride in an L-29 or L39 without too much trouble.

At our old hanger there was a perfect condition L-39 that was stored right behind the aircraft we were using. If you pushed the plane back a foot too far there would be some very unhappy people. I always wanted a ride in that jet but it only went out of the hanger once or twice a year. I decided to buy a lotto ticket instead because there would be a better chance of getting lucky.

 

[pete177]

You need to inspect your tanks and fuel lines very soon. This is a contamination problem, possible old fuel varnish or tank sealant... You haven't by chance ran auto gas or any fuel additives through it have you?

The mechs are gonna seal some leaks in the tanks and in the process do some sanding of the old sealer so they'll be flushing the tanks during that process. After the first incident I started running Heet (the right type, forget which one now) and marvel mystery oil to clean up the lines and injectors. The first incident occured during winter and the second 6 or 9 months later in Florida in august. I think I started running the Marvel after that. Ran fine with the marvel in it but I only had a chance to fly maybe 50 hours running the marvel. The first clog occurred a few hours after annual where the injectors had been cleaned. I had about 150 hours of trouble free (well, injector trouble free) flying before that. The injectors were cleaned again using a sonic cleaner and they stayed clean for 6-9 months before clogging again in florida. Time between flights doesnt seem to have any bearing as the first event occured several short flights after a 6 week pause and the second occurred two long flights after a 10 day pause. I do get some sediment in the fuel sample from one wing, appears to be sealant. Wouldnt the filters catch it though? Could be the injectors are being clogged by debri and then blowin fuel back out the air bleed holes. The event is rare though so I'm not really sure what it could be. Actually, its twice in 270 hours.

 

[pete177]

At our old hanger there was a perfect condition L-39 that was stored right behind the aircraft we were using. If you pushed the plane back a foot too far there would be some very unhappy people. I always wanted a ride in that jet but it only went out of the hanger once or twice a year. I decided to buy a lotto ticket instead because there would be a better chance of getting lucky.

The FBO here has an L29 and will give you a ride for the right price. I think his fuel costs were around $350 for a half hour but the L39 costs were cheaper due to more efficient engine. I think his air show rides were $500 for a 1/2 hour but dont quote me. I know very little about these aircraft so I would imagine a google search and a few phone calls would get ya a ride or at least some idea of the feesability of it all. There are advertisements in trade a plane for L29/L39 training so I know there's people out there running these jets for profit. My impression is that many of the owners of these aircraft would love for you to pay for an hour or two of they're flying Heck, you can buy an L-29 for 75k, my recollection is that the operating costs were ofcourse, rediculous when compared to a 75k recip. 350 knots is nice, but not at those fuel burn rates

 

[Henning]

The mechs are gonna seal some leaks in the tanks and in the process do some sanding of the old sealer so they'll be flushing the tanks during that process. After the first incident I started running Heet (the right type, forget which one now) and marvel mystery oil to clean up the lines and injectors. The first incident occured during winter and the second 6 or 9 months later in Florida in august. I think I started running the Marvel after that. Ran fine with the marvel in it but I only had a chance to fly maybe 50 hours running the marvel. The first clog occurred a few hours after annual where the injectors had been cleaned. I had about 150 hours of trouble free (well, injector trouble free) flying before that. The injectors were cleaned again using a sonic cleaner and they stayed clean for 6-9 months before clogging again in florida. Time between flights doesnt seem to have any bearing as the first event occured several short flights after a 6 week pause and the second occurred two long flights after a 10 day pause. I do get some sediment in the fuel sample from one wing, appears to be sealant. Wouldnt the filters catch it though? Could be the injectors are being clogged by debri and then blowin fuel back out the air bleed holes. The event is rare though so I'm not really sure what it could be. Actually, its twice in 270 hours.

Sounds like tank sealer to me, especially if it's degraded to the point where you are having leaks anyway. What fuel filters do you have? A gascolator will not necesarily seperate it out depending in its density and consistency.

 

[Gary Sortor]

The first clog occurred a few hours after annual where the injectors had been cleaned. I had about 150 hours of trouble free (well, injector trouble free) flying before that. The injectors were cleaned again using a sonic cleaner and they stayed clean for 6-9 months before clogging again in florida.

1. Stay away from annuals. I always seem to have a problem or two after annual.

2. Stay away from Florida. All my problems are in Florida. Of course, I live here.

 

[pete177]

Sounds like tank sealer to me, especially if it's degraded to the point where you are having leaks anyway. What fuel filters do you have? A gascolator will not necesarily seperate it out depending in its density and consistency.

According to the tech manual (if you can call it that) the only screen mentioned is at the fuel selector valve. Does that make sense? Only 1 screen and no filters?

Pete

 

[Henning]

According to the tech manual (if you can call it that) the only screen mentioned is at the fuel selector valve. Does that make sense? Only 1 screen and no filters?

Pete

Yeah, that's what I remembered, and yes, in a way it makes sense. You don't really need anything that strains out stuff much smaller than the smallest orifice in the fuel system. By doing so you create extra risk of clogging the fuel system (at the filter) that isn't really necessary.

 

[pete177]

Yeah, that's what I remembered, and yes, in a way it makes sense. You don't really need anything that strains out stuff much smaller than the smallest orifice in the fuel system. By doing so you create extra risk of clogging the fuel system (at the filter) that isn't really necessary.

Ok..I like simple Mung in tank cloggin the injectors...got it Thanks

 

[bbchien]

Pete, your M20 has toast for sealant. It is ultimately more economical to have the entire tank STRIP and reseal or to put in the Onan Bladders. This is pricey- about $6K. I've owned two Mooneys- an M20F, and TurboJ the former with 63g, the latter with 100 gallon tanks. I tried to temporize on the F with this spot reseal, that spot reseal, but on the J I just said "do it from the top". Ultimately the 100 gal J was cheaper from a fuel tank/clog/leak point of view.

 

[pete177]

Pete, your M20 has toast for sealant. It is ultimately more economical to have the entire tank STRIP and reseal or to put in the Onan Bladders. This is pricey- about $6K. I've owned two Mooneys- an M20F, and TurboJ the former with 63g, the latter with 100 gallon tanks. I tried to temporize on the F with this spot reseal, that spot reseal, but on the J I just said "do it from the top". Ultimately the 100 gal J was cheaper from a fuel tank/clog/leak point of view.

I want the bladders, but I've been putting it off. More like $6500 installed. A tank reseal will run me about 5k. I'm gonna let the guys do what they can and see how it works out, $1000 is their limit The tanks have been resealed before so maybe with a little extra work they can manage a few years of leak free service. Right tanks leaking a bit too much for the IA to be comfortable with it (a few feet behind the exaust) so if we can get that one sealed up some for a bit I'll go that route. Once I get to Texas and into a hanger I may go into the tanks myself and do a complete reseal. Once the motor's back in it and I retrieve it from ND I'd like to keep the airplane together long enough for me to finish my instrument and a CFI ticket.
I didnt know the J had 100 gal tanks. Did they come that way standard?

 

[Henning]

I want the bladders, but I've been putting it off. More like $6500 installed. A tank reseal will run me about 5k. I'm gonna let the guys do what they can and see how it works out, $1000 is their limit The tanks have been resealed before so maybe with a little extra work they can manage a few years of leak free service. Right tanks leaking a bit too much for the IA to be comfortable with it (a few feet behind the exaust) so if we can get that one sealed up some for a bit I'll go that route. Once I get to Texas and into a hanger I may go into the tanks myself and do a complete reseal. Once the motor's back in it and I retrieve it from ND I'd like to keep the airplane together long enough for me to finish my instrument and a CFI ticket.
I didnt know the J had 100 gal tanks. Did they come that way standard?

I'm personally not so sure that bladders are that great of a deal, although they do add a small margine of safety in a crash. They're more expensive, and it's not like they last forever. From the limited experience I have with Mooneys, what I see is that a proper and complete tank reseal lasts about as long as a set of bladders, however, that is with a strip and redo. As far as patchwork goes, I haven't seen that be the wiser system. It costs more over a 5 year basis in maint costs as well as adding to downtime and lost fuel. If it's all you can afford at the time, well it's all you can afford, but if you intend to have the plane for more than 3 years, you'll be money ahead to redo the whole tank(s) even if you have to borrow money to do so if you can. If you can't, you just do what you can. Like the old man said, "Ain't nothin' wrong with bein poor, it's just so damn inconvienient."