bad fuel

T

Tom on Icarus

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Sep 15, 2007
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C Dory Year
2008
C Dory Model
25 Cruiser
Vessel Name
Tranquil~C
Hi everyone. My question for the brats today is this....can dirty fuel get past the external fuel/water filter iinto the internal filter and plug it up?
The reason I ask is...a couple of weeks ago I filled my starboard tank and instantly noticed the honda 75 running rough at idle...even stalling.
When I got home I removed the external fuel/water filter and it was full of fine krud. I bought a new filter but the engine still idles poorly.
I would replace the internal filter too but don't know how to get at it.
Any tips before I take it in for an expensive servicing?
Thanks
Tom
 
Tom,

You could try switching to the other tank and running the motor long enough to get that tanks fuel into the motor. It could be that the newly bought fuel in the starboard tank is bad or has low octane or to much alcohol.
 
Yes to that Larry. I have switched tanks and the problem does not go away. This leads me to believe that some krud has gotten past the first filter into the outboard's internal filter...or worse...into the carbs and is fouling a low speed jet.
I am not much of a mechanic but I try to understand what could be the problem before throwing myself at the repair shop's mercy.
Also notable is....the new filter/separator seems to be doing it's job as the 8 hp kicker idles fine.

Tom
 
Tom, it sounds like you got water into the internal filter. Replacing the external filter/separator solved the problem up to the internal filter but if you've got "stuff" there it has to be replaced. I don't have a Honda or a Honda manual but the Yamaha manual gives a clear procedure for cleaning and replacing the internal filter - as has every other outboard I've owned.

Before you start paying the mechanic $99/hr to do the job, check your manual. After all, it could happen when you're offshore or in a quiet cove somewhere far from a mechanic's touch and you might need that skill to get home.

Don
 
Tom:

If your motor suddenly runs rough at idle, but all right at higher speeds, it's unlikely your secondary filter is plugged. If it passes enough gas to run at speed, it sure should pass enough to idle.

Before doing anything else, I suggest you drain each of the carb bowls onto an absorbant pad by successively unscrewing the drain screws located on the starboard side, at the bottom of the float chambers on the carbs. If you can, collect some in a glass, and see if you have water. Whether you see water or not, pump the primer bulb until it gets hard (you should hear the bowls filling), then drain one bowl again, just to see if the gas you get out looks any different. Then, pump the primer bulb again, and start it up. If it still runs rough, you know there's enough gas, since you just filled the bowls. So, you've either got some solids past the filter which have plugged a jet or passageway, or, more likely, you have bad gas. Dump in a little Sta-Bil or Startron additive.

Let us know what happens.
 
Have changed engine filters on Honda 45's and Honda 90's. Should be the same.

Lift cowling and look on left side of engine (looking from the boat). It's a white bowl thing held in with a clip. Release the clip and work the filter up where you can pinch the spring metal clamp thingies and slide them back down the rubber hoses (about 1/4" hoses, black) away from the filter. Pull the hoses off and replace the filter. It's disposable, cost around $10.

Good to have an extra one on board. It's a little awkward but you can do it in the water. Easiest with engine tilted up a little but not all the way.

Good luck.

Charlie
 
So far (with your help) I was able to remove and change the internal fuel filter. Tight fit in there but I figured that if others can do it so can I.
I did notice that the fuel that came out was totally clean. I even shook the filter up to stir up any junk inside before pouring the gas through a white cloth.
My next step is to drain the carb bowls if that is still necessary since the filter appeared clean.
I sure appreciate all your help. This is a great forum.

Tom
 
Tom:

Suggest you still drain the bowls. They are a catch point in the fuel system, by design. Just a half turn counterclockwise with a flat bladed screwdriver will do the trick. For any future draining, get a flat sheet of absorbant from West Marine, fold into four, and carry in a ziplock bag so you can dump the bowls if you ever need to while underway.

If you want to have some fun with the old filter, drain all the fuel out, put it in some water in the same position it mounts on the motor, let it fill with water, then lay it down on a hard surface, cover with a cloth so you keep dry, and smash it. Then, you can pull out the filter element, and see what, if anything, was caught inside. The water makes a mess, but guarantees you won't end up blowing your head off. Always key to the benefit plan.

Let us know.
 
Although a filter has a certain porosity, there will be some particles larger than that size which will get past it. Common Racors (which is the type of filter I use) come in 30 micron, 10 micron and 2 micron. Generally in inboards, one uses a 10 micron on the external filter, and a 2 micron on the engine filter. I am not sure what the Honda filter is.

I agree, if you got bad gas, there is a possibility that it had some water in it. The ethanol now put in fuels compounds the situation, since it tends to disolve some of the material in the tanks which may have precepitated in the battom.

Definately drain the bowls--and I would would probably want to pull some fuel out of the tank into a clear jar to see if there is any water in it. If the jets have debris in them, then they will have to be cleaned. There are some additatives which will help to clean jets--such as Sea Foam. It might be prudent to check the spark plugs also at this point.
 
Thanks to everyone for their help.
I will drain the bowls today but I don't know when I will be able to sea trial it next.
I'll keep my fingers crossed in the meantime.

Cheers
Tom
 
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