In line fuel filter for 2 stroke outboard

[sy_gilana]

Hi, 2c...The OP asked how the crap got through the fine mesh standard filter. Well it didn't it was created in the carb. The crap got in there in solution, which means molecular size, ie. unfilterable. In normal use, an outboard will suck the whole mix up and burn it. The impurities in the fuel will leave deposits. IF the oil you are using is not tcw3 rated, it will leave more deposits because 2t or m/cycle oil is designed to not burn until it gets really hot, and outboards NEVER get to those temps unless there is something wrong. Tcw3 is designed to burn at a lower temp, and it might contain ammonia whose job is to attract water and transport it through in emulsion. Also OB oil has an adhesive additive to retard drying and run off.

Anyhow back to the OP, the stuff in your carb was made in your carb, and I have nothing against extra filters, save that it could retard fuel delivery and induce air. If you leave your outboard for longer than a month, disconnect the fuel hose, while running, then pull out the choke and open the throttle Wide Open, keep pushing and pulling the choke to control the revs to normal levels. When the fuel is nearly used up it will lean-off and the revs will increase, at this point pull the choke out and let it die. This will coat the inside of the engine with a rich smear of oily gas, and will remove fuel from the carb. The gunk is a residue left over by evaporation, where the lighter fractions of the fuel mix disappear first, leaving ever heavier elements behind. IF you leave you hose connected (stoopid) it will pump more fuel in every day with diurnal heating and cooling, all the non return valves in the system will see to that...the result is you can land up with essence of gasoline in the carb bowl, looks like treacle, and is best dissolved with methanol. (methylated spirit)

No filtration will stop that.....

WHILE I AM HERE....just a word of advice to all fellow croozers. If you are in the habit of tilting your motor at night, please let it cool for 5 minutes in the vertical position before tilting. When tilted, the water will not drain out completely. The residual heat from the engine will evaporate the pools od water inside the engine, leaving salt and calcium deposits, and will over time result in an overheating engine.

Another another thing...the idle jet in most outboards will need to be replaced every 2 years or so in the Caribbean or elsewhere where there is moisture in the fuel. It causes erosion of the hole to a bigger size. As the hole is so small (#45 on Yamahas) an increase of 1 thou is like 20% richer.
Symptoms will be difficult starting and a "sneeze" at idle. Quick fix is to turn the air screw out a half a turn, but get a new jet...you will love the difference.

Hope this helps......



Soo now you see what crap we learn while cruising...

[Therapy]

Originally Posted by sy_gilana

WHILE I AM HERE....just a word of advice to all fellow croozers. If you are in the habit of tilting your motor at night, please let it cool for 5 minutes in the vertical position before tilting. When tilted, the water will not drain out completely. The residual heat from the engine will evaporate the pools od water inside the engine, leaving salt and calcium deposits, and will over time result in an overheating engine.


...

Interesting.

Maybe that is the reason some have that problem and others don't (with the same motors).

Thanks for the opinion.

[thinwater]

Originally Posted by sy_gilana

Hi, 2c...The OP asked how the crap got through the fine mesh standard filter. Well it didn't it was created in the carb. The crap got in there in solution, which means molecular size, ie. unfilterable. In normal use, an outboard will suck the whole mix up and burn it. The impurities in the fuel will leave deposits. IF the oil you are using is not tcw3 rated, it will leave more deposits because 2t or m/cycle oil is designed to not burn until it gets really hot, and outboards NEVER get to those temps unless there is something wrong. Tcw3 is designed to burn at a lower temp, and it might contain ammonia whose job is to attract water and transport it through in emulsion. Also OB oil has an adhesive additive to retard drying and run off.

Anyhow back to the OP, the stuff in your carb was made in your carb, and I have nothing against extra filters, save that it could retard fuel delivery and induce air. If you leave your outboard for longer than a month, disconnect the fuel hose, while running, then pull out the choke and open the throttle Wide Open, keep pushing and pulling the choke to control the revs to normal levels. When the fuel is nearly used up it will lean-off and the revs will increase, at this point pull the choke out and let it die. This will coat the inside of the engine with a rich smear of oily gas, and will remove fuel from the carb. The gunk is a residue left over by evaporation, where the lighter fractions of the fuel mix disappear first, leaving ever heavier elements behind. IF you leave you hose connected (stoopid) it will pump more fuel in every day with diurnal heating and cooling, all the non return valves in the system will see to that...the result is you can land up with essence of gasoline in the carb bowl, looks like treacle, and is best dissolved with methanol. (methylated spirit)

No filtration will stop that.....

WHILE I AM HERE....just a word of advice to all fellow croozers. If you are in the habit of tilting your motor at night, please let it cool for 5 minutes in the vertical position before tilting. When tilted, the water will not drain out completely. The residual heat from the engine will evaporate the pools od water inside the engine, leaving salt and calcium deposits, and will over time result in an overheating engine.

Another another thing...the idle jet in most outboards will need to be replaced every 2 years or so in the Caribbean or elsewhere where there is moisture in the fuel. It causes erosion of the hole to a bigger size. As the hole is so small (#45 on Yamahas) an increase of 1 thou is like 20% richer.
Symptoms will be difficult starting and a "sneeze" at idle. Quick fix is to turn the air screw out a half a turn, but get a new jet...you will love the difference.

Hope this helps......



Soo now you see what crap we learn while cruising...

Good post. He is correct in that much of the junk is "generated" in the carb. I have add extra filters for only 2 reasons:
* In the case of phase separation, having a Raycor-type filter gives you a place to drain water. This is only and e10 problem, and is generally only a problem if water leaks into the tank. However, I did have a boat with a deck-mounted tank that loved to separate, mostly because of the temperature extremes it saw.
* Some small outboards (my 3.5 Merc) have no replaceable filter, only a stainer in the tank. That's dumb.

Where does the stuff come from? Some is corrosion products. Aluminum with brass parts is vulnerable in e10. Corrosion inhibiting treatments help, but some of the additive vendors are liars (no big surprise, huh). Practical Sailor is running tests. Even more interesting is that there has been a task force formed among additive producers and engine manufactures to develop additive specs. Apparently there are some additives they find harmful, and they want to develop and "approved" list. I'm looking forward to it.

Some are from oxidation and evaporation, as stated. I'm planning on setting up some long-term tests regarding that next.