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Home / Airframe Parts / Fuel Systems / Fuel Additives /Decalin RunUp Fuel Additive
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Decalin RunUp Fuel Additive

42 Reviews 17 Answered Questions
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16 Oz Quart
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Overview

Decalin RunUp is approved for use with the new 100VLL (Very Low Lead) fuel announced by the FAA on Special Airworthiness Bulletin NE-11-55. Decalin RunUp contains two types of additive, one to reduce the negative effects of tetraethyl lead in aviation fuel and the other to improve the combustion efficiency, reduce combustion deposits and clean the fuel delivery system in aircraft. Users can expect the same level of engine cleanliness when using this fuel and Decalin RunUp as they saw with 100LL.

Make sure you remove and clean your oxygen sensor every 20 hours to remove these lead phosphate deposits when using Decalin RunUp.
The dosage of 1/2 ounce per ten gallons of fuel is a minimum. This can be increased to a maximum of 2 ounces per ten gallons for problem engines.

Decalin RunUp is not approved for use in the engines of certified aircraft but it has the same active ingredient, Tri Cresyl Phosphate as our previous product. Lycoming clone users have reported very good results when using this product.
RunUp MSDS

Notes:
Some white deposits may be seen on the plugs and in the exhaust pipe during use; this is normal with RunUp since the lead in the fuel is being converted to non conductive lead phosphate. When no additive is used, lead oxide is formed. It is lead oxide which causes plugs to misfire due to its partial conductivity shorting out the plug. In addition, lead oxide tends to form in large clumps or clinkers whereas the lead phosphate is crumbly and if anyy is left behind in the combustion chamber it deposits in even layers.

Features

  • Scavenges Lead in aviation fuel after combustion to prevent lead oxide buildup on valves but still allows the lead to perform the anti-knock function prior to combustion.
  • It is an excellent additive for auto conversions, where it reduces buildup on oxygen sensors and plugs. If you have to use 100LL, then this stuff is for you.
  • Prevents valve seat erosion from valve seat micro welding. It is equivalent to TCP (for experimental only).
  • Does not contain volatile solvents so it is safe to ship and safe in the cockpit. You can carry it with you for out-of-town airports.
  • Easy to use graduated measuring and dispensing reservoir built into the bottle. No messy syringes!
  • Tested and stable down to 0 degrees F.

Documents

  • Decalin Chemicals SDS
  • Frequently Purchased With
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Reviews

Submit a Review

This additive works very well minimim plug fouling. Find that the price is higher than other options. Shipping cost is very high.

Robert M Verified Purchase

Decalin RunUp Fuel Additive Quart

March 26, 2025

I have been using Decalin in C-85s and O-200s, for many years. It does an excellent job of keeping the spark plugs, free of lead fouling. After using it for a year, you’ll be surprised at how clean the plugs are, at next annual.

Joe B Verified Purchase

Decalin RunUp Fuel Additive Quart

November 27, 2024

Terry W Verified Purchase

Decalin RunUp Fuel Additive 16 Oz

November 19, 2024

This stuff work great in my little A65! Keeps the valves clean!

Joseph L Verified Purchase

Decalin RunUp Fuel Additive 16 Oz

October 23, 2024

Have used this additive for many years. Has helped greatly when I am forced to use avgas in the Rotax engine.

Klaus T Verified Purchase

Decalin RunUp Fuel Additive Quart

August 3, 2024

James W Verified Purchase

Decalin RunUp Fuel Additive Quart

June 5, 2024

Ive been using Decalin Runup on my Rotax 912 ULS for the past 7 years. It flies 10-20 hours a month. After 1,100 hours burning 100LL exclusively, there is almost zero accumulation of lead - only a slight film in the bottom of the reservoir every 300 hours. This stuff is amazing!

Austin L Verified Purchase

Decalin RunUp Fuel Additive Quart

May 25, 2024

Don B Verified Purchase

Decalin RunUp Fuel Additive 16 Oz

May 14, 2024

On time and as advertised.

Brian F Verified Purchase

Decalin RunUp Fuel Additive 16 Oz

February 14, 2024

Does what it’s supposed to.

Ron J Verified Purchase

Decalin RunUp Fuel Additive 16 Oz

December 27, 2023

Buell P Verified Purchase

Decalin RunUp Fuel Additive Quart

November 6, 2023

Ingenius, easy to use dispenser!

John M Verified Purchase

Decalin RunUp Fuel Additive 16 Oz

September 27, 2023

John M Verified Purchase

Decalin RunUp Fuel Additive 16 Oz

September 26, 2023

Decalin is excellent for reducing the bad effects of lead in avgas

Klaus T Verified Purchase

Decalin RunUp Fuel Additive Quart

August 10, 2023

helps keep plugs clean, and can be safely transported without HAZMAT, easy measurement dispenser

Maureen D Verified Purchase

Decalin RunUp Fuel Additive 16 Oz

April 28, 2023

OK

Lowell T Verified Purchase

Decalin RunUp Fuel Additive 16 Oz

February 11, 2023

Works great

Ivan Verified Purchase

Decalin RunUp Fuel Additive Quart

December 23, 2022

Chris C Verified Purchase

Decalin RunUp Fuel Additive Quart

November 16, 2022

Effective to prevent carbon deposits in combustion chambers, especially for Jabiru engines operating with low EGTs. Using it for a decade now. S. Berger

Berger E Verified Purchase

Decalin RunUp Fuel Additive Quart

April 26, 2022

Works as advertised! My old Franklin cant use 100LL without it!

John A Verified Purchase

Decalin RunUp Fuel Additive Quart

January 13, 2022

Very easy to dispense. Works well to control deposits in the combustion chamber.

Todd L Verified Purchase

Decalin RunUp Fuel Additive Quart

October 5, 2021

AAA+++ EXCELENT!!

Omar M Verified Purchase

Decalin RunUp Fuel Additive 16 Oz

August 31, 2021

I use this in my experimental aircraft. It does what it is supposed to do.

Dale W Verified Purchase

Decalin RunUp Fuel Additive 16 Oz

July 21, 2021

Use religiously in Rotax to avoid lead build up.

Curtis L Verified Purchase

Decalin RunUp Fuel Additive Quart

June 29, 2021

Using this keeps my plugs clean.

Curtis I Verified Purchase

Decalin RunUp Fuel Additive Quart

June 24, 2021

Have used Decalin for many years in a Rotax 912 engine whenever I had to use Avgas. Has worked very well. There has never been a build-up of lead in the engine.

Klaus T Verified Purchase

Decalin RunUp Fuel Additive Quart

June 16, 2021

Excellent product, delivered to Australia on time, exactly as promised.

Alan M Verified Purchase

Decalin RunUp Fuel Additive Quart

June 1, 2021

I use Decalin in my IO-320 and O-290 to help scavenge lead deposits, It really keeps the spark plugs clinker-free and eliminates pre-ignition and detonation. It especially makes a huge difference in smoothing out low rpm idle.

Bob
April 8, 2021

Great product

Monty
April 5, 2021

This item arrived on time and exactly as advertised. I will carry it aboard my plane and use as described. It comes highly recommended by from my aircraft distributor and many experienced users. I have not used the product yet.

Larry A
February 12, 2021

ordering and shipping was excellent, this product seems to be exactly what I was looking for..

Michael R
November 9, 2020

Must have for xctry flights in the SuperStol when 100LL is the only option for the Rotax. Excellent product and performance at a great price from Aircraft Spruce....as usual.

Loren
February 27, 2020

Great product...good value!

John F
February 13, 2020

Easy measure bottle and good lead fouling reduction in lower compression engines.

Charles R
October 3, 2019

Too soon to tell its effectiveness. My forum members on the 150/152 club swear by it. They are an astute group of owners whose opinions I value.

Antonino
August 25, 2019

I use 1 oz per ten gallons on my UL350 engine. It works very well when running 100LL.

Ronald G
July 11, 2019

As a second owner of fairly new aircraft that has Lycoming tio 540, I have been having problem with lead fouling and hard starting. I came across this product and tried it for a year. I never had experience hard start, no lead fouling spark plug, and engine run smooth as they’re supposed to be. I increase the ratio to 2oz per 10 gal. I will borescope all cylinders and see the effect of Decalin Runup. To make easy dispensing, used a large syringe 2oz.

Alexander L
November 12, 2018

I had to double the ratio in order to keep the plugs from fouling. Also noticed that the fluid changed color from yellowish to clear. Great product.

Carsten H
June 18, 2018

Must use this with 100LL or my old Franklin breaks rocker arms and sticks valves.

John D
January 18, 2018

been using this product for 2 years now in Lycoming IO360 with excellent results. Its difficult to assess engine efficiency without laboratory testing. However, the reduction/elimination of lead deposits on valves and especially spark plugs is is very obvious. At annual the plugs show almost no lead build up. Before using Decalin the lead build up was significant over a year. I heard about this from engineering friends at General Atomics who used it on their drones with great success.

William R
October 29, 2017

Seems to prevent, in a certain extent, the carbon deposit in the combustion chambers. At least the deposit is less dense, more friable/brittle. Might clean up on its own.

S. B
September 2, 2019

I cant comment on the function of the product because I havent used it long enough to evaluate. However, I do have comment on the package design. The package is designed to pour a small measured amount out. When the container is new and full, I couldnt dispense the 1/2 OZ or 1 OZ quantity. The design allowed more fluid from the main tank to come out. I found that at least until you dispense a few ounces, a suction bulb or syringe is easier to use.

James P
March 1, 2018
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Q&A

Submit

Please note, Aircraft Spruce's personnel are not certified aircraft mechanics and can only provide general support and ideas, which should not be relied upon or implemented in lieu of consulting an A&P or other qualified technician. Aircraft Spruce assumes no responsibility or liability for any issue or problem which may arise from any repair, modification or other work done from this knowledge base. Any product eligibility information provided here is based on general application guides and we recommend always referring to your specific aircraft parts manual, the parts manufacturer or consulting with a qualified mechanic.

Q: Can you harm Decalin Runup fuel additive if its stored outside in the winter? I had some from a few years ago and had it stored outside in a plastic tote, and looks like the container leaked. Does this stuff freeze? I never looked at the bottle in the winter.

This product has a two year shelf life so yours may not be good anymore. This product is table down to -60 degrees C. This will not freeze or separate at any temperature. Please see the tech data sheet in the 'Documents' tab for more information.

Q: If someone had failed to use Decalin with many hours of Avgas use in a Rotax 912, can using it for any or many hours afterwards, with unleaded fuel REMOVE to any degree the previous lead deposits on valves or other parts retroactively?

The short answer is yes. This has an advanced deposit removal ingredient which will remove existing deposits. Depending on the quantity of the deposit, this may take time to achieve, but generally one or two full tanks of fuel will do the job. Fuel injectors and throttle bodies get cleaned up as well at the same time.

Q: Can Decalin be used with auto fuel? I use both 100LL and Auto fuel in my aircraft.

Yes, Decalin Runup is compatible with auto gas. Decalin should be added in proportion to the 100LL being added. There are no negative effects to doing this.

Q: Is Decalin RunUp compatible with composite construction fuel tanks? (Specifically, fiberglass cloth and EzPoxy 10A Resin/ 87B Hardener).

Per Vendor, Yes the Declain Runup is compatible with fuel resistant composite fuel tanks along with fuel resistant fiberglass cloth and epoxy resins and hardeners.

Q: What is the case quantity of Decalin Fuel Additive, Part # 05-03412? ie how many quarts in a case?

10 quarts per case.

Q: After adding Decalin for the first time to 100LL, on my next flight a few days later during the pre-flight sump check I noticed a separation of fluids in the sample -- about the same amount as the Decalin added. Could that be the Decalin settling and I should not have drained it, or unrelated? I have never detected water in previous sump checks.

Per the Supplier: All our experience so far says that this issue is unrelated to the addition of Decalin RunUp to 100LL. The ingredients in this product are miscible in all proportions with aviation gasoline. To speculate, cold weather causes condensation in fuel tanks, so this issue may be more related to the season.

Q: Will Decalin Runup have any impact on lead that ends up in the oil?

The active ingredient in Decalin RunUp follows the “lead” of the lead, if you’ll excuse the pun. It reacts with a majority of the lead in the fuel to produce lead phosphate which is mostly blown out of the exhaust. Remaining lead in unburnt fuel finds its way into the oil by bypassing the pistons. The ingredient is already dissolved in the fuel and goes with it into the oil sump. There it acts as a suspending and dispersing agent, preventing the lead from precipitating and agglomerating into an abrasive sludge. It also performs other useful duties by helping to remove carbonaceous deposits in the oil galleries.

Q: I see there is a shelf life of 2 years. Is thi after opening? If so, what is the shelf life of unopened container kept in cool dry dark storage?

Shelf life is 2 years from the date it is shipped to us. This is unopened, and storage would not add to shelf life.

Q: Hi this is a follow-up question in regards to the remaining lead that goes into the oil you had commented that it helps. Keep the lead particles in suspension in the oil will it do the same and synthetic oil because this is the main reason synthetic oil is not compatible with leaded fuel, could you use let it fuel safely in an engine that is using synthetic oil ???

Yes, Decalin RunUp will work just as well with fully synthetic oil in suspending the lead in the oil. There is a limit as to how much lead it will hold in solution and here is some reported data in a Rotax engine using synthetic oil. The results indicate that after 91 hours of operation my oil contained 1098 ppm of Lead (Pb). During the 91 hours of operation I used 49.85 gallons of 100 LL fuel, all of which was treated with Decalin at the rate suggested on the product.

Q: Is there a date stamp on the bottle of the Decalin Runup?

Yes, there is a date code on the bottle.

Q: How many gallons does one quart of Decalin Runup Fuel Additive treat?

The dosage of 1/2 ounce per ten gallons of fuel is a minimum. This can be increased to a maximum of 2 ounces per gallon for problem engines.

Q: Can this Decalin Runup product be used in Rotax 582 engines?

Yes it can be used in the Rotax 582 engine. This is a two stroke engine and we have a number of customers who have had good results using Decalin RunUp in them, with reduced valve and combustion chamber deposits and a smoother running engine.

Q: The dosage........ is it per US gallons?

Yes it is per US gallons. THIS 16OZ BOTTLE TREATS 320 GALLONS

Q: For proper mixing, is it advisable to add to the tank before or after fueling?

To ensure the fastest initial mixing it is best to put the Runup in first. If it is put in after, Runup will disperse quite rapidly in the fuel, not longer than 10 minutes and less than that if flying.

Q: You mention in the dosage: This can be increased to a maximum of 2 ounces per gallon for problem engines. Do you mean to say 2 ounces per 10 gallons or actually 2 ounces per 1 gallon? Thanks.

What we have on the website is correct per the manufacturer website.

Q: You say that decalin run up has a two year shelf life…is that from date of manufacture or from date of opening the bottle?

2 years from DOM.

Q: I have been using Ethanol Free Unleaded autogas in my O-200 engine, but when away from home the Unleaded is hard to find. Is there any prohibition on putting this product into tanks that are mixed 100LL and Unleaded Autogas?

Decalin RunUp is miscible in all proportions and compatible with both 100LL and Unleaded Autogas. There is no limitation. Add RunUp in proportion to how much 100LL you have, at = oz per 10 gallons of 100LL.

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