Detecting Water in Fuel

As you will gather from the text, Paul Ireland has been hosting Zoom technical seminars for the TR Register (the reference to ‘TR Action’ is the magazine of the [Triumph] TR Register, which is published eight times a year).  Paul has been hosting these seminars as an adjunct to his incredibly successful book ‘Classic Engines, Modern Fuel’.  The article which follows was written by Mike Boling of the Essex Group of the TR Register, and I am grateful to the Register for permission to reprint it in TTT 2.      

Many regular readers of TR Action will be aware of the excellent book by Dr Paul Ireland entitled Classic Engines, Modern Fuel. Paul has recently hosted exceptionally informative Zoom technical seminars on this subject specifically for TR Register Members.

There are many factors why our classic engines may not like modern fuels (all explained in easily understood detail in the book and during the seminars) and the potential damage that modern petrol may do to fuel delivery systems.  One of the problems with ethanol-blended petrol is its ability to absorb water and the corrosion problems the oxygen rich ethanol & water combo can cause.  The most likely route for water to get into your fuel system is condensation inside a near empty tank, rain during filling or exceptionally, from the forecourt tanks.  The problem of water in underground tanks has been with us for ever and, although modern storage tanks are much less likely to be affected, the potential still exists and when it gets into a tank it will eventually result in “phase separation”. Water, water absorbed fuel with gasoline on top. (Most petrol sites these days do have electronic water-level detection in the tank…Ed)

Replacing fuel lines, gaskets, diaphragms, seals etc. etc. with ethanol-proof components is relatively straightforward and inexpensive but, when it comes to petrol tank corrosion that’s a whole different ball game.  During periods of inactivity, the ethanol contaminated element of the petrol will settle at the bottom of your tank (and carburettor bowls) and start to corrode the metal.  Tank seams are especially vulnerable as those who have experienced the “smelly boot syndrome” will attest! 

Fortunately, there is an easy way to find out if you have water contamination in your petrol tank.  Splash out a mere £12 on a tube of “Kolor Kut” water finding paste available from Amazon (other brands and vendors exist).  This product has the consistency of toothpaste and is a beige-golden colour.  Coat the bottom 20mm of a clean bamboo cane with the paste and carefully probe down to the base of your tank.  Withdraw the cane and if the paste has turned bright red, you have water contaminating your tank.  The colour change occurs within seconds so long immersion is not needed or recommended.

If you have tested positive, the only solution is to drain the tank and thoroughly dry it out, note that some fuel or water will be below the bottom outlet pipe.  If you have to go this route, please remember that you are working with a potential bomb and take every possible precaution against detonation.  Only work in the open air, not in your shed or garage and be aware that the slightest spark may prove disastrous!  The empty tank will contain explosive vapours so remain vigilant.

There are products on the market with which you can coat the inside of tanks to make them “ethanol proof”.  I know several people who have tried a variety of these, all with disappointing results so be careful and do your research before you part with your pennies.

Mike Boling, Essex Group

Editor’s Note: In the introduction to Mike Boling’s short article, I referred to Paul Ireland’s “incredibly successful book”. It has sold 2,000 copies worldwide and is currently in reprint – better order your copy from Veloce Publishing now! All royalties from the book go towards helping children’s education in Tanzania and an article about this was included in Issue 65 (April 2021) of TTT 2. To buy a copy of Paul’s book, please go to

3 thoughts on “Detecting Water in Fuel

  1. jan Mazgaj says:

    Had the following product suggested to me. Admittedly by Frosts but in conjunction with “Kolor Kut” may be worth the investment

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