AerostarDriver Posted May 17, 2021 Report Posted May 17, 2021 I keep getting clogged injectors, when I sump the tanks in preflight I effectively never have particulate in the fuel. However, about an hour in to flight, I am getting clogged injectors typically on 3 and 4. After landing and trying to resolve the issue I am finding that I have particulate that is amber in color and feels like grains of sand in the tanks. What has perplexed me is the particulate only appears after flying the plane. Sumping the tanks, leaving the plane for a week and coming back to it yields a clean sump. I am looking for any ideas that may help alleviate my clogged injectors and reduce the amount of particulate that is ending up in the fuel. I believe the correct long term answer is to strip and seal the tanks (or install bladders). While I have accepted this, it is a tough pill to swallow when my tanks have ZERO leaks. In the short term, I just want to make the plane safe enough to ferry to a place to get the tanks resealed. Quote
carusoam Posted May 17, 2021 Report Posted May 17, 2021 Got any pics? Check for rubber hoses downstream... somewhere near the fuel divider... Rubber fuel hoses have been known to shed inner layer parts... PP thoughts only, not a mechanic... Best regards, -a- 2 Quote
KSMooniac Posted May 17, 2021 Report Posted May 17, 2021 I'd start by opening the gascolator and checking for junk there, and especially the condition of the filter screen. Sent from my LM-V405 using Tapatalk 1 1 Quote
AerostarDriver Posted May 17, 2021 Author Report Posted May 17, 2021 (edited) 17 hours ago, carusoam said: Got any pics? Check for rubber hoses downstream... somewhere near the fuel divider... Rubber fuel hoses have been known to shed inner layer parts... PP thoughts only, not a mechanic... Best regards, -a- All fuel hoses have been replaced over the last 5 years. Not ruling this out as a possibility but the particualte is in the tanks at the end of the flight. Their should not be enough back flow through the lines to bring it back to both tanks at the end of the flight. 16 hours ago, KSMooniac said: I'd start by opening the gascolator and checking for junk there, and especially the condition of the filter screen. Sent from my LM-V405 using Tapatalk I just pulled the Gascolator screen, SB/AD filter and screen in the fuel servo at annual 4.3 hours ago. All of them had small amounts of the amber color particulate but also large amounts of black/gray proseal looking chunks in them but I was not sure what wing they were from. The back story on my airplane is last year the wing was replaced and that wing had pretty large leaks. My IA and I assumed the proseal looking chunks were from the old wing as the previous owner had never seen this amber colored particulate before. I am about to pull them all again and check, however, I suspect they are all going to be pretty contaminated. I also am going to pull all the lines from the fuel selector forward and blow them out. Update: My IA is going to drain and borescope the tanks. We plan on trying to flush the tanks to see if we can nock as much of the loose sealant off as possible and see where we end up. Edited May 17, 2021 by AerostarDriver 1 Quote
Yetti Posted May 17, 2021 Report Posted May 17, 2021 What's in the finger screen in the servo. When was the last time the servo was rebuilt? Quote
AerostarDriver Posted May 17, 2021 Author Report Posted May 17, 2021 50 minutes ago, Yetti said: What's in the finger screen in the servo. When was the last time the servo was rebuilt? I have not yet pulled the servo screen (Pulled it 4.3 hours ago and it was contaminated with same stuff in the screen and filter), will be doing that tomorrow. An overhauled servo was installed when the engine was rebuilt in 2014. Quote
carusoam Posted May 18, 2021 Report Posted May 18, 2021 Particulate in the tank at the end of the flight.... Fuel is only going one way.... towards the selector.... Two things known for making particles in Mooney tanks... Rust bits... found in 60s Mooneys where the fuel neck isn’t SS... Sealant... found in fuel tanks that haven’t been resealed in decades.... Pics of the particles would really be helpful... Some things that have settled in fuel tanks have come from the fuel source.... Have you spoken with the fuel supplier? PP thoughts only, not a mechanic... Best regards, -a- Quote
Bartman Posted May 18, 2021 Report Posted May 18, 2021 23 hours ago, AerostarDriver said: Update: My IA is going to drain and borescope the tanks. We plan on trying to flush the tanks to see if we can nock as much of the loose sealant off as possible and see where we end up. As you stated above the sediment is only detected when the fuel is agitated after flying, not when sitting still prior to flight. I agree with pulling the sump drains and flushing. In addition to flushing lines, screens, and the gascolator I would also recommend opening the flow divider. After having multiple injectors clogged we sent mine to the specialty shop and they reported contamination that we think was from new fuel hoses, but I also understand this can be serviced by your A+P. Quote
AH-1 Cobra Pilot Posted May 18, 2021 Report Posted May 18, 2021 Are the particles ferrous? Do they dissolve in water? Alcohol? Acid? Lye? Etc? If you can determine what material they are, you might be able to tell where/what they are from. I would also suggest looking at them under a microscope to try to determine what their composition is. Quote
AerostarDriver Posted May 18, 2021 Author Report Posted May 18, 2021 1 hour ago, AH-1 Cobra Pilot said: Are the particles ferrous? Do they dissolve in water? Alcohol? Acid? Lye? Etc? If you can determine what material they are, you might be able to tell where/what they are from. I would also suggest looking at them under a microscope to try to determine what their composition is. The particles are non-ferrous, non-metallic and hard like glass or sand. I assume they are coming from the tank sealant that also appears to be amber in color. It also appears to have buoyancy that keeps it suspended in fuel for much longer then any other sediment I have seen in fuel. Alcohol, acetone, paint thinner don't seem to do anything to react to it. 56 minutes ago, A64Pilot said: No one has run auto fuel have they? As far as I can tell, the pervious owner never ran auto fuel and the airplane never had it. The airplane that gave up its wing, was a 74 Turbo E which I would be a surprised if it ever ran on auto gas. According, to the airworthiness information provided by the FAA it never had the auto fuel STC and was purchased the company which did the turbo conversion STC on the E model. Quote
EricJ Posted May 18, 2021 Report Posted May 18, 2021 15 minutes ago, AerostarDriver said: The particles are non-ferrous, non-metallic and hard like glass or sand. I assume they are coming from the tank sealant that also appears to be amber in color. It also appears to have buoyancy that keeps it suspended in fuel for much longer then any other sediment I have seen in fuel. Alcohol, acetone, paint thinner don't seem to do anything to react to it. You sealant is amber? That's a clue, as that's very unusual. There was an alternate, seldom-used sealant mentioned a while back but I can't recall the material. My recollection is that its use was deprecated due to difficulty in removal. Quote
AerostarDriver Posted May 18, 2021 Author Report Posted May 18, 2021 Just now, EricJ said: You sealant is amber? That's a clue, as that's very unusual. There was an alternate, seldom-used sealant mentioned a while back but I can't recall the material. My recollection is that its use was deprecated due to difficulty in removal. I cannot tell if the sealant is amber but the sides of the tanks appear amber in color, almost like an overdone treatment of alodine. The sealant at the joints can best be described as "dark", color or tone is undeterrable. 1 Quote
N201MKTurbo Posted May 18, 2021 Report Posted May 18, 2021 1 hour ago, AerostarDriver said: I cannot tell if the sealant is amber but the sides of the tanks appear amber in color, almost like an overdone treatment of alodine. The sealant at the joints can best be described as "dark", color or tone is undeterrable. For a while they were using a polyester sealant. It was supposed to last forever. It turns out that is is almost impossible to remove. How about a pic of the inside of your tank? 1 Quote
PT20J Posted May 18, 2021 Report Posted May 18, 2021 On 5/17/2021 at 6:17 AM, AerostarDriver said: Update: My IA is going to drain and borescope the tanks. We plan on trying to flush the tanks to see if we can nock as much of the loose sealant off as possible and see where we end up. That's what I would do. There are ribs in the tank bays that stuff can hide behind. Perhaps something got into the tanks when the replacement wing was off. Ultimately, you might have to open up the inspection covers on the top of the wing to really inspect and clean everything out. Skip 1 Quote
AerostarDriver Posted May 19, 2021 Author Report Posted May 19, 2021 On 5/17/2021 at 12:39 AM, KSMooniac said: I'd start by opening the gascolator and checking for junk there, and especially the condition of the filter screen. Sent from my LM-V405 using Tapatalk That is what came out of the gascolator screen and the left tank. 1 Quote
carusoam Posted May 19, 2021 Report Posted May 19, 2021 Looks like you may have found it... Take a look at this pic... it looks like the sealant is cracking and falling apart in some areas... on these rivets... Get your hands on it and see if it is breaking off like the picture shows... it matches the color, and the size as described... PP observation only, not a mechanic... Best regards, -a- 1 Quote
N201MKTurbo Posted May 19, 2021 Report Posted May 19, 2021 The sealant looks like the normal polysulfide. The topcoat looks odd. They may have used the polyester instead of lithe liquid butyl rubber. Have you looked in your log books for a clue? Quote
N201MKTurbo Posted May 19, 2021 Report Posted May 19, 2021 If it is a continual problem, I would pull three covers and put a new top coat on. It’ll be about $50 in material and about 8 hours of labor. It will hold any flakes in place and give you a proper top coat. Quote
AerostarDriver Posted May 19, 2021 Author Report Posted May 19, 2021 7 hours ago, N201MKTurbo said: The sealant looks like the normal polysulfide. The topcoat looks odd. They may have used the polyester instead of lithe liquid butyl rubber. Have you looked in your log books for a clue? The wing was replaced last year by Don maxwell, I manage to find a few pages from the log book of the donor airplane from an archived for sale listing and an NTSB report. None of the airframe logbook pages show anything useful other then lasar did the repairs on the wing for the gear up on the donor airplane. As far as I can tell they did good work because I can find no evidence on the wing of a gear up. Quote
AerostarDriver Posted May 19, 2021 Author Report Posted May 19, 2021 8 hours ago, carusoam said: Looks like you may have found it... Take a look at this pic... it looks like the sealant is cracking and falling apart in some areas... on these rivets... Get your hands on it and see if it is breaking off like the picture shows... it matches the color, and the size as described... PP observation only, not a mechanic... Best regards, -a- I observed the cracking on the rivet tails and in one photo their is just general cracking. I tied to break some off with my finger and a wood dowel. Even with the cracks, I was not able to get any material to come off. Doesn't mean it can't but my IA is confused, his exact words where "that looks way better then I was expecting, but there is no clear smoking gun." 1 Quote
PT20J Posted May 19, 2021 Report Posted May 19, 2021 If you are going try recoating, I might test a small area to make sure the new topcoat is compatible with the old. Quote
N201MKTurbo Posted May 19, 2021 Report Posted May 19, 2021 I said it was polyester, but I meant polyurethane. https://www.meggitt.com/insights/discover-our-leak-proof-long-life-sealant/ 2 Quote
carusoam Posted May 20, 2021 Report Posted May 20, 2021 PU is typical for it breaking up into sand like pieces... not hard as sand though... it still may have a rubbery compression to it... Some PU can be incredibly tough... very hard to damage... (more modern technology the newer the PU is... this century vs. 1970) PU also likes to stick to itself... this may be helpful if repairing an older layer of PU... PP thoughts only, not a polymer chemist. Best regards, -a- Quote
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