Gas dripping out of engine...right before Powell trip, too.

S

Sunbeam

Active member
Okay, I'm down in the dumps here. After all the work on the boat I've done, and all the potential boating I could have done in that time.... well, I was okay with it all. I wanted to get my boat to a certain spec, and that takes time (my choice). The one carrot on the end of the stick I did not want to miss was this fall's Powell trip.

Now, on the eve of departure (and with the local Yamaha shop having just closed until Tuesday morning), I find that my main engine, a carbureted Yamaha F80, is leaking fuel (gasoline). Not cool! And I can't figure out where it is coming from, or exactly how it happened. So ... yeah.. dejected :cry:

If anyone cares to read my clues, and has any ideas, I would be appreciative. While I'm not a mechanic, I'm a good sleuth and I can check things.

So, for as long as I've had the engine.... no fuel dripping anywhere. Granted, for a long time there was no fuel in the engine. Around 2-3 weeks ago, I pumped fuel into the engine for the first time in a long time (after having replaced the fuel system on the boat) and ran it on the muffs. No fuel was noticed. The engine was left both tilted down and tilted up at various times. I did not drain the fuel system, and nothing leaked that was noticeable.

Wednesday, we trailered around 40 miles and ran the boat for the first time. Put a few hours on the engine. Then it was tilted up, supported in the "up" position, and trailered 40 miles back and parked. The engine was left "up" until yesterday, when we tilted it down to measure the AV plate height. We left it down from then until today, and no fuel was noticed. A few hours ago, we tilted it up because I needed to modify the trailering support wedge. So we tilted it up and down a few times, then left it up and went to a workbench for around an hour to modify the wedge. When I got back I smelled gasoline. I looked and saw brown "globules" in the little bit of water that stays in the splashwell (drain allows a small amount of water to sit there). It had not spread out into "rainbows," like you would think gas would, but was instead sitting there in brown circles, not spreading out. But dipping a paper towel into it it is unmistakably gasoline, and not oil or etc.

There is clearly no gas dripping out of any of the hoses, the filter, or anyplace else. I found two brown lines coming down the motor cowling handle (just below the bottom of the cowling), but nothing sprayed around on the inside of the cowling. Hmmm. Then I found that there is a small hole in the bottom of the engine skirt (the part that is the bottom of the cowling that doesn't come off, if that makes sense). That hole has a little rubber stopper type thing in it (factory), and the gas had leaked out of there, and (now I could tell) through the gap where the handle/arms of the latch go in. So in other words gas had somehow pooled in the bottom "skirt" part of the engine below the cowling, and then dripped out when the engine was tilted up today. Not sure why it is a little bit thicker and "syrupier" than pure gas, but maybe that is a clue?

I looked all around inside the engine but can find nothing leaking. The built in fuel filter and hoses and joints are all dry, there is nothing obviously sprayed around inside anywhere. The carbs smell like gas if I put my nose up to them - I would presume that might be normal but.... is it?

The engine started easily and ran beautifully on the maiden voyage - no missing or any signs that gas was not being used efficiently.

I guess this fuel must have been in the bottom there and just dripped out when I tilted the engine today, but then.... why would it not have dripped out on the way home trailering? Would it have leaked *since* then? And why was it more brown circles on the water and not a thinner sheen?

I sure would appreciate any input on this - I don't want to miss Powell, but also don't want to head there with a new-to-me engine dripping fuel. These things always seem to show up five minutes after the Yamaha shop has closed for their weekend (which is Sunday and Monday). :cry

Sunbeam

PS: I don't know of photos will help, but I'll add some in a bit.
 
Here are a few photos.

An overview of the port side of the engine, which seems to be the side with most of the fuel components. Please ignore the annotation on this first photo - that is left over from when I was replacing the rectifier (that was 100% successful, thanks to the C-Brat help :thup).

You can see the fuel filter in the after/port corner (small orangish cylinder). It and its connections are dry and don't smell of fuel when wiping over them with a paper towel.

IMG_1365.sized.jpg

overview.jpg

Here I've pointed out where the gas left the engine and dripped out. Not really a mystery as there are "gaps" in the skirt at those points. So that's just where the gas got to when the engine was tilted, I believe.

gas_dripped_from_here.jpg

If you can look past the dirt (why does it always look so much worse in a photo?), you can see the brown globules. I thought it was interesting (maybe a clue?) how it stayed in globules vs. spreading out more. It smells like pure gas though, not like anything else in the way of oil or lube.

gasoline_globules.jpg
 
Sounds like you had a float that did not shut properly, for reasons that we can only speculate ...
I wouldn't worry about it.
A lot mechanics recommend running the carbs dry before storing or transporting the boat.
Enjoy your trip to Lake Powell
 
Hi Sunbeam. I would get some oilsorb pads to keep one in the splashwell for a while. Keep the gas out of the lake. It doesn't look bad to me, and being a Yamaha it'll run well. Go do 400 miles or so on the road tomorrow and get on down to Powell. It is likely a stuck float or dried out gasket swelling from lack of use. Go use the boat. These are work boats not yachts! Enjoy Powell. George
 
Thanks to both of you for the replies. I let a couple of friends talk me down out of my tree enough to go have dinner -- just got back and checking in to the forum.

So you think it might have been a sticking float? Does that fit in with the engine running perfectly well (both at idle and at speed)? It is true that it was sitting basically "dry" for quite a while, so I could see a gasket drying out, now that you mention it. I bought the boat over a year ago, and at that time had all four carbs rebuilt and then all the fuel drained out of it (knew I would be working on the boat for some time and didn't want to gum up the carbs again!).

I did tilt the engine up 100% today, when I normally only tilt it about 75% of the way up. I was working on the engine support wedge at the time. Before I posted I put it back down to 75% tilt, and I can say that it doesn't look like more has leaked now, over the past few hours. Maybe running the carbs dry is a good idea (?) How does one do that when the fuel hose cannot be disconnected? (I grew up with small outboards; we just pulled the fuel hose clip off and let them run dry at the end of the summer.) I'll look in the manual and see if they recommend it or not.

From another angle: What other things might cause gas to leak while the engine is running? (Just knowing what the possibilities are will make me feel more prepared.)

I sure don't want to not go to Powell (or to go later and miss the group get-together at Oak Canyon like I had to do last year). I have been looking forward to this all year! But I want to feel reasonably sure everything will be safe and okay, both while running and while "living" in the cockpit.

Thanks again for replying. I'll read up on sticking floats and such. Also I'll keep an eye on the thread so if anyone else posts to it, I'll see it.

Sunbeam

PS: I do have some fuel "diapers" aboard for use when fueling. I'll cut off a piece and keep it in the motorwell - good idea.

PPS: George, if you happen to read this, I was meaning to ask you what you use to support your Yamaha 90 when tilted for trailering. I think the bracket may be similar to mine, which doesn't seem to lend itself to anything (although I did customize the M/Y Wedge today to hopefully make it work better).
 
Yes, answering myself again :wink: But still thinking about this and trying to visualize and understand it. So does this sound logical? I'll write it in steps so you can point out where I've gone wrong (I don't really know how these work, so just thinking out loud):

1) So of course fuel is in the carburetor bowls when running the boat, but that's normal. Then I suppose some must just stay in there when you shut the boat down, presuming you don't run it dry (I didn't).

2) But normally still no gas leaks out, even when you tilt the engine. (Right?)

3) So okay, somehow gas did leak out of my carbs, seemingly when I tilted the engine all the way up today vs. my usual 75% tilt level (this was a couple days after running the boat). Does it leak out the top of the carbs? How does that relate to a stuck float?

4) If it did leak out the top of the carbs (I don't know if that's even possible), would it then come out the air intake? Because that is right above where the fuel must have pooled in the forward/bottom "skirt" area. That might explain why there is no "gas trail" anywhere else in the engine that I can see.

I guess I'd like to understand how the carbs and fuel would normally act when tilting up the engine, and/or/if how a stuck float or etc. would change that. Then I can use this to learn more about my engine :thup

Sunbeam

PS: Here is a photo that shows what I think is the air intake (vertical silver woven grille)

air_intake_fuel_q.jpg
 
Now that I knew what to search for, thanks to your replies, I did some reading around in the various outboard/boat forums to learn more. It sounds like it's not uncommon for carbs to leak a small amount of fuel at extreme tilt angles. And I guess then it may (or does) come out the air intake, which is right above where it dripped from. I had the engine tilted up farther than usual (all the way) today while working on the support wedge.

So.... whew! I mean, it sounds like there *could* be other, more "sinister" reasons, but unless/until it happens again, or more copiously, I'll go on the apparently common, "carbs can leak at extreme angle of tilt" theory.

I will keep an eye on things. And I don't have any immediate reason to tilt the 100% of the way up again either. Thanks again for the input. Whew! (because.... not a good time to need a Yamaha shop visit).

Sunbeam

PS: Yes, I did read a few mentions that a fuel-injected engine would be one "fix" :smilep
 
Put the 'muff on the Yamaha, pressurize the fuel line and run the engine. While the motor is running carefully inspect the areas where fuel seemed to have dripped-out. If you see anything leaking it may give you a clue as to the problem (IF there is a problem). Naturally you'll want to be VERY careful when being that close to a running, unshrouded motor.

Have a good flashlight and a small mirror handy and give it all a close inspection. A little toilet paper tucked into suspected areas will help reveal any new leaks or drips.

Unless you see a problem ... head for Powell!

I suspect the previous comments about a stuck carb float any/or a dried-out gasket may be the culprit.

Best,
Casey&Mary
 
It could just be the vent lines on the carbs. When tilted all the way up gas ran out the vents. Run the engine like Casey said and see if anything is leaking. Then drain the carbs and tilt the engine all the way and see if you still get gas leaking. There should be a vent line from the carbs that just terminates somewhere. That's probably what I would look at first. If it isn't leaking in the running position I would just drain the carbs and goto Lake Powell.
 
The pic doesn't look like gas to me...if it was gas you wouldn't see it. Must be oil and grease and maybe a little gas...I bet it is residue from the cowling that has been there a while and worked it's way out with the up and down on the motor. Whenever you work on the motor...whether changing the oil or servicing the carbs...you always drip something into the cowling...and it is impossible to clean it all up unless you completely tear it down.
The carbs each have a vent port that will pour fuel into the cowling if a float sticks. It will be anything from a little drip to just pouring out the side of the carb.
Load the boat up and come to Powell. If the thing breaks...we'll just fix it!
 
Hi Sunbeam. I tilt down on a short piece of 2x4 to support the engine. I tie it in place just in case. I used to use a 1" dowel. It broke on I 5 south of Bakersfield. Rough road! My mechanic says the motor needs support for long tows. Good luck. Enjoy Powell.
 
Thanks for the additional replies, good advice, and encouragement. I will follow it :thup I do have a carb draining question at the bottom of the post.

Potter Water:
I do think it was at least mostly gas because.... well, just because I have a good nose, and to me gas doesn't smell like oil or lower unit grease or any of the other lubes I know of that would be in the vicinity. But I do agree with you and Chris that it must not have been pure gas, because it pooled "oddly," as you could see, and with pure gas I would expect a thin surface film and rainbow, not an undissolved circle.

What I think now is that it probably was gas that traveled over some grease on the way out (such as, there is a large glob of grease on the inside of the latch mechanism, and there were two "trails" coming down the latch face from where it came out through that gap in the skirt) and maybe they blended slightly in the process.

Casey: Great ideas for testing. Not sure why I didn't think of that last night (guess I was in a bit of "noooo, this can't happen right now" mode).

Jody: I will look to see where the vent lines are and how they terminate - good thing for me to know anyway. I know where they come out on the Honda (kicker) but not the main. Not only did I raise the engine 100% of the way, but it just so happened that I let it go all the way to the upper stop, so it did a slight "hit the brakes" motion as it touched. If anything would slop gas over the top of something... I guess that would be it. No reason to tilt it that high now that I have the support wedge customized.

Chris: Thanks :D I don't like to start out a trip with a known problem (and then potentially burden others with needing to help), but I like your "Come on down!" offer and spirit :thup (And it sounds like I probably don't have an actual problem, most likely - but I'll suss it out more today.)

George: I do run with the engine supported, but the design of the bracket on mine seems to be made to defy all attempts to do so! I think I now have the M/Y Wedge customized to work better, but if you get a chance to take a photo some time, I'd like to see how the 2x4 fits on your bracket (maybe it's different on the 90). I'll try to take a look at what Chris uses too (he has a 75). I got a chance to look at a Yamaha 40 the other day, and shoot, that engine bracket practically reaches out for a 2x4, and it fits in beautifully -- wish mine were like that.

Carb draining question:
One question that I don't think shows in my manual: Specifically how do I drain the carbs? This is something I need to know anyway. I had them drained by the mechanics who went over my engine when I first bought it, so have never done it (and now there was only going to be gas in them for a week or so on the way to Powell, so I was potentially just going to leave it...)

I do remember the mechanic telling me that the fourth (bottom) carb was a bit of a bear to get to. I have read that there might be clear tubing that I put over something on each carb while it drains? (Maybe that was Honda specific.)

I will go take a side-on photo of the carbs and then post it. Maybe someone can then draw a "circle and arrow on the backside" or otherwise describe how to drain them?

Thanks,
Sunbeam
 
Sunbeam,
Do not sweat it. You know the engine runs fine. You better get on the road, and get down there. The guys will help you if there is anything major, which I doubt.

I would agree with running for a few minutes on the muffs, look for any obvious fuel leak--but this looks like only a few drops--maybe a CC at the most. Gas on water spread on the surface and a few drops can look like a lot. Most likely a stuck float--if it is a problem, you will see it--but I suspect it is temporary and the road trip will bounce things around.

Get going!
 
Will do, Bob :D

While we are on the topic though: How long is too long to leave gas in the carbs? Having paid someone to rebuild all four (due to the PO leaving gas in the carbs for a looooooong time), I'm not keen to do that again!

I'm happy to drain them when necessary to keep them from gunking up, but of course don't want to do it unless I need to (especially #4... that looks pretty hard to reach *#^/*!). Right now I have non-ethanol fuel in my tanks (yay!), along with Yamaha Ring Free additive (plan to put that always). I have blue marine Stabil on hand, but wasn't going to add that unless/until I need to. So I guess I have three questions:

1) At what "sitting" time frame would you add blue marine Stabil vs. figuring you were using the fuel fast enough to not add it.

2) With non-ethanol fuel in the carbs, how long would you feel comfortable letting them sit without draining them between uses?

3) With ethanol fuel (which will only taint my system if there is no other choice, but that's bound to happen sometime) in the carbs, how long would you feel comfortable letting them sit without draining them between uses?

Thanks, as always,
Sunbeam
 
Yes those look like the drains and the bottom one looks like you would have to take the bottom cover off to get to it. Unless you have a trained mouse for the job. :roll: The vents or overflows might or might not have hoses on then depends on the motor. Like Bob says button it up take a trip there will be plenty of people around to help out if there's a problem.
 
Yes...the brass plugs are the bowl drains. The hole that the blue line intersects in the second photo is the vent...if the float sticks fuel will flow out of that hole. In a bind you can remove the plug and tickle the float with a piece of wire (gently) to get it unstuck.
The two other things you asked about are the prime/start components. These enrich the fuel on a cold start...kinda like a choke...but work differently. Solenoid on top...thermal component on the bottom...have no effect on a warm start.
 
Even if I have ethanol free fuel, and am not going to run the big outboard for 2 months I will drain it. If ethanol--a month. With smaller outboards I run the carbs dry each time I put it up and store it on its side or back. With the Honda, if not going to run it in a month I drain it. I try and run the generator each week if not running it daily and leaving fuel in it.

The Honda 90 is easy to drain the carbs, and shutting off the fuel still leaves a little fuel in the carb.
 
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