Having a weird thing happen and was wondering if anyone had any ideas on what was going on.

After my motor sits up over night the fuel in the clear filter gets a brownish tint. I know (or at least think) that it is not anything to do with the fuel tank because as soon as you start running the motor it clears right up.

Couple of notes:

I did over fill the oil (I think I must have had motor tilted back when I filled it) and ran it that way for a little while (couple of hours maybe) but have since drained off the extra oil. I then pulled the bowl off carb, cleaned the bowl and jets, pulled the breather tube and blew it out, and sprayed carb cleaner in the breather inlet to the carb and up into the bottom of carb on float etc. Also pulled filter and cleaned it out. Have run it a couple more hours, but still doing it.

It is a 36 carb on a 32 PD.

It seems to be running ok-but not getting quite the power I expected out of it. I don't have a baseline as it is on a new boat and did some work on motor before I put it on. If it is oil, just can't figure out where it would be coming from....

Pic attached- Any one got any ideas?

filter2011.jpg

ethanol breaking down in sunlight

a guess but oil residue in you lines

Take some straight out the tank and put in a glass jar and see what happens.

How did the gas / bowl on the carb look? Any gunk or gel?

It has to be the gas out the tank, everything else is down stream. Have you run any kind of additives like octane booster? Certain brands will make it darking up like that.

some yahoo pissed in your gas tank after they drank a monster!

Not coming from the tank. It clears up when the motor is run. Turns that color after sitting for a few hours.

Bowl and jets were clean. No gunk or gel.

He did have almost a quart too much oil in it. Could that have caused a problem with the carb somehow?

I have not gotten to run it yet, but he says he is lacking power as well. Boat does not want to flatten out. I run an identical boat with a 36 and same mods, cam, heads, exhaust and my boat runs great. I was getting 25 or so with whatever I put in the boat at 3600 or so rpm's (wrong spring). He is barely getting 25 empty, only running 20 or so with a relatively light load, and turning closer to 4000. He's tried a 32 and 36 prop with not much difference.

My Fuel filter did that for the first few hours on my motor when it was new. Now it dosent do that anymore..

i had the same issue earlier this year. i put a fuel/water seperator in inline and the fuel cleared up instantly. also how old is the gas?

Didn't make any sense to me how it could be working it's way all the way through the carb and back down to the filter, but the fuel coming out of the tank is clear. Guess, like you guys are saying, it could just be discoloration from the sun.

Couple notes in response.

Please don't take any of it as argumentative as I promise you I don't know what is causing it and am looking for any ideas anyone has.

Fuel Additive-yes, put Stabil Ethanol in it at fill up.

Have a fuel water separator on it.

Also, actually first noticed when there was a small leak on carb (where the anit-backfire plug screws in). There was a tint to the gas that was leaking out that I thought was odd. This was not in the sunlight as it was resting on cav plate and boat was backed up under a barn. Also noticed the fuel discoloration in filter at that time (when boat was under shed).

Fuel coming from tank is definitely clear. Only other thing I would comment on about the sunlight is that it did it under the shed and it will do it overnight. Meaning I will run the boat in the evening and then when I go out the next morning, it would be discolored already-mind you I wasn't going out at dawn so it had sat in the sun for awhile both in the evening and that morning, but it wasn't a long time-and it would be that way after it I ran it under the shed and it never saw any sunlight (other than any indirect). Filter would also have more gas in it the next morning than the evening before-so gas was draining down from carb somehow....

Does have new fuel line.

Carb bowl did have discolored gas in it. No gel or heavy residue, but there was definitely some brown tint to it.

I was kind of assuming that the excess oil was somehow getting up in the carb-I had no idea how that could happen and even would think it was somewhat impossible unless it was coming up thru breather tube- but like I said it still did it even after I lowered oil level and ran it for several hours. I can tell you plugs were fowled horrible bad-but I switched them out.

Gas is brand new.

I will run out the discolored gas and then cover it to see if it is the ethanol.....

Like I said, I can't say for sure motor is not running right, but sure seems to not be pushing like I would expect it to based on previous motor performance (without latest mods) on other boat, and performance on similar setups.

Any other thoughts would be appreciated....

Thanks guys!

switch to using regular unleaded w/out ethanol. should be running this on a small engine anyway. if it was oil in the gas to tint it that much you would be seeing smoke i would think for a little while after fire up.

I had the same thing happening with my stage 1 (EVT) PD the entire time I owned it. It has to have something to do with the clear filter exposing the fuel to UV rays. Even under a shed or in a building with windows some UV will reach it. I didn't do anything about it but run the dog sheet out of it and it had NO effect on how the motor ran. If it really bothers you, get rid of that clear filter and you won't see it any more!!

I would bet the inside of your fuel line is deteriorating from the Ethanol, and when the fuel sits you are seeing it in the filter. I had this happen last season. Just a guess...but it sounds familiar. Has the boat been sitting for a while with gas in the lines?

Does have new fuel line.

I should have read your post...it was too long....

Ethanol is hard on rubber fuel line. With the addition of the additive I bet it is coming from fuel setting in the line. Also while those glass fuel filters look good they are very restrictive. Just look how much flow is blocked where the ends screw on. Chunk that thing a d replace with a good unrestrictive fuel filter and you may fix your performance issue.

i have the same filter, exact same issue except for the performance. after idling for a few minutes it clears up.

Well, did a test last night. Fired it up and ran it for a while. Gas in filter was clear. Wrapped the filter in a paper towel and then two rags.

This am went out and took it off and the gas had the brown tint again. Don't know if the UV's can get thru that or not....

Either way, just going to move on and not worry about that right now. I will assume it is not part of my problem (that may or may not even be a problem) and focus on other things for now.

Was mainly just wanting to know if anyone had seen it before or knew exactly what it was.

Thanks guys....

Also like SP said new fuel line is breaking down from the ethanol if it is a black line then the rubber is being stripped very slowly (oil in the rubber) after a while the hose will look like it is sweating(year or so) and actually is micro pinholes in the line, I see this alot when making biodiesel which uses ethanol in the process, a lot of older trucks fuel lines have to be changed to newer ethanol resistant hose, when using bio but there is new marine hose for this. also on another note I have see this happen when your engine starts starving at high rpms because air is getting into the line and the fuel pump can't suck from the tank as well because of the pinholes. The gray marine hose seems to cope with this Better. Ethanol is the devil!!!!!

Ethanol is the devil!!!!!