Trying Again

Today we chose to bite the bullet and crack on with the petrol issue with the starboard engine. It was a miserable day weather wise so we took the opportunity to do something useful instead of sitting around all day.

We had spoken to an engineering company close to the boatyard the other day and they suggested a couple of things for us to test. We've already tinkered with the ignition side of the engine but this made no difference.

We started by swapping the black rubber fuel hose from the petrol pump to the carburettor for a clear braided hose so we could inspect the fuel flow as we accelerated. Thing started badly as the engine would not start and we realised that the petrol was not reaching the carburettor. This was strange as we had not had this problem before. We left things there and removed the fuel filters to find they were packed with this green sludge that we discovered in the starboard fuel tank when we purchased Bandit. We ditched the two filters (one larger filter in-line with the copper fuel lines and one on the engine) and replaced them. We also purchased a new set of filters as spare. We then fired the engine up and this appeared to make a noticeable difference. The fuel reached the carburettor and the engine seemed to run better already.

I then disassembled the midships cabin to gain access to the fuel tanks. A closer look in the starboard fuel tank revealed clean petrol with no visible sludge. This is good as we're fairly sure that it's all been sucked through and got caught in the filters.

Then was the real rest. We took a trip up the river and found that, although the engine performed a lot better, it still had this issue where the revs would suddenly drop from 2000 to 1000rmp and would then stutter. However, we only had 0.5m under the keel and I could feel the duo-propellers digging into the riverbed. It looked as if the fuel flow was good and consistent so we're a little confused at the moment as to what the issue is and where. We also noticed that the engine would rev a bit higher than it had previously done.

We've considered this first river trial inconclusive as we couldn't really put the power down due to depth. When we have a nicer day and we can head down the river a bit where it's deeper, we'll put it to the test once more and see what happens. Things aren't looking good and we're running out of ideas.

The only other thing that we might suspect is the inlet manifold gasket leaking slightly or the carburettor gasket (between the inlet manifold and the carb). This carb gasket is thinner than the ones we've previously purchased and Dad reckons it didn't sit right on the manifold anyway. We're going to purchase another new thick gasket, replace it and see what happens. When replacing the carb gasket, we will also double check the in-line fuel filter at the carburettor to ensure nothing has got stuck there. We didn't check it that long ago but you can never be sure until you've looked...

This problem is either down to:

  1. Fuel
  2. Ignition
  3. Leak in a gasket somewhere

And so it continues...


  1. Not sure how I ended up on here but anyway here's my thought. You mentioned that you had water in the fuel which if has reached the carburetor will make the rev's go up and down as you mentioned. These have very small sensitive parts and spray nozzels and a a float that can get easily blocked and water gets trapped in them. If you have not already take the whole carburetor off and let you local engineering company strip it and clean it. Its a simple cheap job that will be worth it.

    1. Thank you for the advice! We had a look today and found that it was on the ignition side of the engine and not the fuel side. We took the carbs apart and cleaned them anyway. Best wishes. :)


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