Carburettor or injection for distance seafaring

[fergie_mac66]

We have a catalac engine 25hp outboard worked well for 18 years problem this year tho now corrected prompt a question on replacement. If we have fuel problems (and we have had from ios gurnsey jersey and other places) it takes me 30 mins to take a carb of and replace with a spare, with 45 mins to clean the removed. I can do both in a seaway and have 50 miles of tge coast. New outboards seem to be pushing injection forward,more expensive prolly better fuel consumption. However bad fuel supplied with water content, e10 fuel even with dual fuel filters and water separaters, what happpens to injection pumps and injectors, i doubt i can swap 50 miles out at sea even 2 miles. Is the better fuel consumption worth that risk is it possible to switch pump / injectors as easily as a carburettor even allowing for onboard replacements?

 

[thinwater]

Keep the fuel dry and you should not have a problem with the carb for the life of the motor. I've been living with e10 for over 30 years (US chemical engineer).

• Make sure the filler O-ring is good. If portable tank, keep the vent closed when not in use. This is the ONLY way you can get enough water to separate. If you are worried about absorption, add a silica gel filter.
• Water separators do not work with e10. If you get so much water that it separates ...
  • It will be 10% of the tank volume, which is too much for a filter.
  • The water phase is actually 80-90% ethanol and is not heavy enough to separate in a separating filter. Too slow.
  • The water phase is 80-90 % ethanol and water-repelling and coelescing elements will not reject it. It's not water, it is wet alcohol, and it will go right through.
• Corrosion can also be a problem, as it causes blockages. Use Stabil 360 Marine, Biobor EB, or Merc Quick Store. These stop carb corrosion. Other products may be snake oil.

Injection systems on outboards I cannot speak to.

 

[fergie_mac66]

Keep the fuel dry and you should not have a problem with the carb for the life of the motor. I've been living with e10 for over 30 years (US chemical engineer).

• Make sure the filler O-ring is good. If portable tank, keep the vent closed when not in use. This is the ONLY way you can get enough water to separate. If you are worried about absorption, add a silica gel filter.
• Water separators do not work with e10. If you get so much water that it separates ...
  • It will be 10% of the tank volume, which is too much for a filter.
  • The water phase is actually 80-90% ethanol and is not heavy enough to separate in a separating filter. Too slow.
  • The water phase is 80-90 % ethanol and water-repelling and coelescing elements will not reject it. It's not water, it is wet alcohol, and it will go right through.
• Corrosion can also be a problem, as it causes blockages. Use Stabil 360 Marine, Biobor EB, or Merc Quick Store. These stop carb corrosion. Other products may be snake oil.

Injection systems on outboards I cannot speak to.

Yes carbs i have no problem with thank you for info regs water I have had water probs this year tho uncertain as to source had nearly 2.5 liters in 10 galls had to swap carb 2ce as bubles water in float chamber transferd fuel to clear container settled and removed good fuel however engine is 98 yam we have seviced a few times butat 26 year old is long in tooth had gearbox failure and coil failures and fuel pump failure plus water in fuel this year but inquiries all are pushing injection and I am dubious about long term and offshore repair. On a estuary ok not far from land but crossing to roscoff and further seems a big safety complication I and my wife like self sufficiency

 

[thinwater]

I would check for source of water in gas. If water in gas from the pump actually occurred one time in 10,000 there would be boycotted gas stations. It is ALWAYS a water leak related to the boat or storage. It just is.

Sometimes water absorption from the air is a factor, but not on cars because the fuel system is effectivly sealed. But a boat tank breaths, and if it absorbs some water in the warmer season and then you go somewhere cooler, the water becomes unstable and suddenly separates.

Just keep it dry.

phase separation

 

[William_H]

I would imagine that if like a car then it wopuld be far easier to replace an injector which has become blocked than a carburetor. Presumably 2 injectors for 25HP. In reality my experience with 4 stroke injected O/b is that they are really good. Start easily reliable and economical. I don't have experience of ethanol fuels however. ol'will

 

[ChromeDome]

When buying fuel on longer journeys, there can be significant differences in fuel properties which might also be worth considering.
Over here, it is extremely rare for petrol to go off, even if people store it for years.

In summary, although petrol quality can generally be considered high in developed countries due to regulatory standards, there are significant differences in how fuel is classified and what it contains. These factors can affect vehicle performance and consumer perception of fuel quality. Understanding these differences is crucial for consumers travelling between regions or who own vehicles tuned to specific fuel types.

We can still get 100 octane (RON) with 5% vegetable juice, and diesel without juice, marketed as Marine fuel - and more expensive. The diesel variant is also sold as Off Road diesel (for use in everything other than road transport).
People who use regular diesel often add a treatment additive.
Most have filtration as prescribed by the manufacturers, and when water is found in fuel it's always from leaks at the user's end. Bacterial growth is very rare.

A note on Octane Ratings: In the United States, gasoline is typically rated using the Pump Octane Number (PON), which is the average of the Research Octane Number (RON) and the Motor Octane Number (MON). This results in lower numbers on the pumps compared to Europe, where fuel is usually labeled with just the RON. For instance, a fuel with a 95 RON in Europe would generally equate to a 91 PON in the U.S..

• Europe: Common ratings include 95 RON for regular unleaded and up to 100 RON for premium fuels.
• United States: Standard options are usually 87, 89, and 91 PON, which can confuse consumers who assume these numbers reflect lower quality

 

[Refueler]

"In summary, although petrol quality can generally be considered high in developed countries due to regulatory standards"

As a Fuel blender for many years - that statement is actually not strictly correct. Yes regulatory standards exist and the fuel blend has to comply. But that does not mean that the components used to create that fuel are high quality. True Gasoline has long not been at the 'pumps' ... all Gasoline except A76 is blended. Even that wonder of wonder Aspen is not true Gasoline !

During blend - we could be using anything up to 12+ 'products' to create the blend. Bulk usually being a low octane gasoline and then high octane additions and chemical additives. The final blend would be tested and en-route ship is detailed to a discharge port .. having sailed 'Subject to Orders'.
The only destination that agrees with the highlighted comment - is when the Octane failed to meet general international specs and then it was routed to West Africa or Caribbean. West Africa would be passed to customer as is ... just hope you had an old Peugeot !! Caribbean - it was then blended off for transfer usually into US market.
Majority blends that met specs were routed EU / UK.

Thinwater will recognise two Lab Terms used extensively by Fuel traders :

Reproducibility
+
Repeatability

as well as precision range of results.

Those factors can give rise to a blend not quite meeting specs - but can be reported as within spec. Crazy but true.

 

[B27]

Based on experience with EFI bikes being many times more reliable and trouble free than small carburettor engines, I would not hesitate to have an EFI outboard. We also find EFI outboards very reliable at the dinghy club.
I don't think you'll get many problems with the fuel unless you store it badly for a long time or you're travelling to the third world.

It's prudent to change the filters reasonably often and take care to keep tanks sealed as much as possible IMHO.

 

[PetiteFleur]

I'm not an expert in fuel constituency but from my experience with Honda 2.3, Honda lawnmower & 2 stroke strimmer, following advice from local lawnmower dealer - I now use Premium petrol - E5 with the Honda additive. Certainly more reliable but have still had problems with the Honda 2.3 with blocked jets etc. Not tried Aspen yet, even though it was recommended by the dealer.

 

[Rappey]

Ive never had any problems with an injection system. Leave the engine a few months and it still fires up straight away.
I've an injection engine that sat for 3 years with fuel in it in the garden. It fired up within 5 secs but ran as rough as old boots due to fuel gone off.
I would take injection over carb every time. I think most people with outboards would agree as it seems a rare thing for one to go faulty.
Carbs are just a pita.

 

[thinwater]

All good comments.

I will go back to -- most problems with diesel and gasoline come from a bad or old O-ring on the filler cap. Lots of good details above, but we can all use reminding to grease and replace the O-ring regularly.

 

[Dellquay13]

I had a 2015 EFI Yamaha 4t 70hp. In 2020 I winterised it, fogging oil into the cylinders etc and laid the boat up. 3 years later I charged the battery, reconnected up the old E10 fuel and it started instantly and without smoke. I wouldn’t hesitate to get another fuel injected engine for long distance seafaring.

I wouldn’t trust any big engine that was old enough to have a carburettor for longevity or for any serious passage making.