Engine run problem

[Roy & Dixie]

Yahama F80 ,1999 carburetored, 4-stroke.

I went out last thing today to warm engine up for @ 5 min to then flush with solution I just bought. Boat had been in river and run for @ 4 hr 2-3 days ago and then run at home using ear muffs to flush. Today when I cranked engine on trailer with ear muffs, it started up immediately and ran at idle for a couple of minutes, then began to miss like it was out of fuel. I changed to a full tank, pumped fuel bulb, and attemped to restart. It fired and stumbled a couple of times, then never fired again. It has ignition from both mags and at spark plugs. (plugs are new). Fuel flows from inline fuel filter as bulb is compressed (outlet line removed). Fuel spirts several feet from lines out of each of the 2 fuel pumps. So I have good ignition and good fuel supply to the carbs. The missing and then engine shut down at that time sounded like it could have been no fuel to carbs or the engine choking down. Now I am led to think fully choked engine, because I have fuel flow and ignition, but I have always been able to start a flooded engine by either waiting a few min or opening throttle fully when cranking. There is not even one sign of engine life.

I'm glad I'm not out at anchor right now. Any suggestions?

[potter water]

Sounds a lot like water or other contaminates got into the carbs. Fuel flow from the pumps won't tell you much about what is going on inside the carbs. Good luck. Others will be able to help while I only speculate.

[thataway]

Any chance of bad fuel or water in the fuel / Carbs? I don't know this specific engine fuel systems. It is possible that there is water in the fuel lines and then got into the carbs? There is usually a water separator in the fuel system after the fuel pump, and this may have filled up with water. Some Yahamas have a float in this bowl, and if there is water in the bowl, then it will shut off the fuel. (Again I don't know if this is the case with your engine--I know it is in some of the 115's of the same era). I would look at the lines, and see if it has this water separator (on the port back side of the 115 I owned).

I woud also open the drains on the carbs, and be sure that there is no water in there.

Edit--Harry beat me by a minute.

[Roy & Dixie]

What has me frustrated is the fact that the engine ran perfectly on water for several hr, and then when I flushed thru ear muffs at home. I had fresh fuel in both tanks, and started off today on same tank I had run on trip and to flush. Thinking back on todays events, the time the engine ran would have been about the length of time I would expect the fuel in the carb bowls to last. It seems something has caused a fuel shut-off to the lines running to them. There are 2 devices mounted on the 4 carbs with 2 wires running to each of them. I'm wondering if these devices somehow shut down the fuel if some problem that I am missing occures.

I will look for a way to drain the carbs tomorrow, and will look for a fuel/water separator. I did nothing that would have gotten water around the fuel system.

[C-WEED]

Sounds like plugged up carbs to me as well. Check your fuel line connection fittings and make sure they are not sucking air. If you have a racor fuel filter with water separator drain that filter/bowl first. Open the fuel bowl drain screws to drain the fuel into a container for inspection. Once drained, leave the drain screw open and squeeze the fuel bulb. Hold the bulb vertical for best pressure. If the lines/filters are clear and the floats are not stuck shut fuel should flush thru the bowl and drain out. Inspect this fuel for debris/water. There are four tiny filters hidden one in each line into each carb. These filters are a last chance to keep debris from the carbs but fuel flow can be restricted. Also these filters do nothing to stop the gumming/corrosion effects of ethanol. If flow is verified to the carbs it is possible to drop all four float bowls from the carbs with them still attached to the engine. You can then give the needle/floats a good flush with carb cleaner. Verify the float opens and closes the fuel flow. Reassemble and if it fires and runs check the fuel tanks for contamination and run a can of sea-foam or B-12 chem-tool thru it.

If it doesn't run the carbs will probably have to be removed, disassembled for deep cleaning. To get it to fire you can remove the air intake so you can see directly into the carbs when standing in the boat. Get a can of spray Sea-foam (Auto Zone). This is much better than starting fluid. Spray a shot in each carb and try to start. If it starts and stumbles you can keep the engine going by spraying short bursts of sea-foam and it might clear up and smooth out.

This engine is very lean at idle (tiny idle circuit) to meet EPA regulations. Also only two of the four carbs have a start enrichment circuit. Like a choke this allows extra fuel to two carbs for cold start. You may have noticed it runs a bit rough the first start of the season or the day. Because only two of the four carbs get the rich fuel it takes a minute for the other two cylinders to fire even and smooth. Do to these tiny circuits it doesn't take much to plug one enough to cause troubles. There are also tiny air passages that vent the carbs. Keeping these open are just as important as the fuel passages.

The two wires to the carbs are the two start enrichment valves. They are simple a needle that rises to open a passage to allow extra fuel to draw in to the carbs when you raise the choke lever. You can remove the clip that holds them and gently lift them up out of the carb. Turn the key to on and raise the idle arm you should see the needle lift up. Take spray carb cleaner and spray down the hole to flush and reinstall the needle. You may have a broken pickup tube in the fuel tank. Also, check you tank vents. Many boats had one of the vent holes facing forward. So when the boat was at cruise water would spray into the vent, into the fuel tank.

You should have a little white filter in the left rear of the engine that you can't quite see into. I prefer to change this out with a clear filter. You can then see the fuel move towards the carbs as you squeeze the bulb. And see any debris in there as well. You can find these at Wall-Mart with three extra filters for about $15.

I agree with Dr. Bob. I have to drive out of the way to transport pure gas for all my engines. After I pay about 30 cents more per gallon I am rewarded with more power, fuel economy and greater reliability.

[Sunbeam]

[thataway]

Are you using ethanol fuel, or "pure" gas. I try and run my boats only on pure gas. (not always successful). When I first discovered the water problem on my 115 Yahama, The engine was running fine, and all of a sudden it stuttered and shut down. I found the bowl, and cleaned it on the water (actually dropped the float overboard and get it quickly back!). Fired up and was OK. But the water had gotten slowly by the Racor, which was regularly inspected and drained. My guess was that the water was slowly accumulating, and got the critical level.

[Roy & Dixie]

Wow, what a treasure of information to draw from today, as I go back out to the CD and begin to work through the fuel system.
1) my tank vents are both outside the boat and face downward, as I remember. This could easily be a source for water to have entered the tanks.
2) I have a Racor filter with drainable fuel bowl beneath. I have looked into the bowl several times, as I did yesterday, and did not see water in the bowl along with gasoline. But the bowl is cloudy enough that the bowl could be full of water and not appear any different than fuel.
3) I do not seem to have the float type filter Sunbeam's 2002 engine has, but I will check again. I do have the small white inline filter that C-Weed noted.

I plan to put all this info together today and first get all the old fuel out of the fuel lines. I have an empty 6gal portable tank from my 40 Yahama poontoon boat. I plan to get fresh fuel in it and connect it to the F80 so as to eliminate all the other possible sources of water. Then if I can get the engine to fire up, I can began the search for the source of water and eliminate it.

I guess that I should look at the "good news" side of all this: It happened here at home on the trailer, not in the swamps of the St Johns River, and I will have learned a lot more about my outboard.

Thanks again to everyone, and especially C-Weed's step by step guideline.

[Roy & Dixie]

Here is a quick update and summary of a successful day getting the Yahama to run.

1) Clean fuel in racor.
2) Clean fuel coming from both tanks.
3) Fuel being pumped to lines running to carbs.
4) Removed carb drain screws; very little fuel noted in fuel bowls.
5) Cranked engine, no fuel into/flow from carb drain.
6) Tried to blow (by mouth) into a line directly to all carbs. Could not blow any air.
7) Removed air intake system to see into carb intake. Clean and each baffle opened/ closed properly
Removed top cover on top carb to view narrow passageways. Clean and dry of fuel.
9) Poured clean fuel into top of carb. Fuel flowed thru and ran from carb bowl drain.
10) Installed that drain screw, refilled top of carb with fuel, and cranked engine. Engine ran on 1 cylinder for a few seconds (with help of starter motor)
11) Removed and disasembled top carb (removed fuel bowl) Everything clean. Float moved up/down, valve parts all in place. No small filters in line leading into carb.
12) Blew through fuel line into carb intake. Could blow in when float was down, could not blow in with float held up. So this float had been stuck up, indicating a full fuel bowl, when engine had burned all the fuel in the fuel bowl. Thus, even with an empty fuel bowl, fuel would not flow into the bowl. During disassembly of the carb I had freeded the float.
13) Since the top carb float became free so easily after disassembly, I simply left the 3 remaining carbs in place and ran a narrow flexable wire tie through the dain holes of each carb such that the wire tie would turn up and rub against the float. As I thrust the wire tie in and out, I could begin to hear the float click as it moved up and down inside the bowl. I confirmed each float was down by blowing into the fuel line to each carb.
14) I reassembeled the top carb, reinstalled it, and reconnected enough linkage, etc to try to run the engine. A few squeezes on the fuel line bulb filled the carbs and the engine fired up like nothing was ever wrong.

I let the engine run for 20-30 min, reving it to 3000 rpm or so every now and then. Each carb has its own throttle return spring and a couple springs were off their hooks, resulting in poor throttle return. I repositioned each spring and adjusted rpm to 900 rpm idle. Then I flushed the cooling system with my new saltaway look-a-like. (blue, foamy discharge) and shut down to let saltaway coating not be washed away.
Tomorrow I plan to get SeaFoam fuel adative and spray carb cleaner. I'll spray into carb with engine running, and add additive to tank that is almsot empty now. This should help clean any deposits from carbs.

Now, what caused all this? My thoughts: The boat and engine are 1999 models, 14 yr old. The tanks total 36gal. The engine had 450 hr on it: = 32 hr/yr average. That means a lot of fuel sat unused for a long time over 14 yr. Then I purchased it and topped tanks and cruised at least 25 hr in 2 weeks, using fuel from both tanks and loosing up deposits from all over the fuel system. Then after a days outing, I went out the next day and cranked up a cold engine for a very few min to flush and blow air through cooling system. I shut down a cool engine and the deposits floating around in the fuel system must have caused all 4 floats to stick in the open position.

[thataway]

Ethanol....Interesting that all of the floats stuck in the closed position--

I believe Marc Grove at Wefings does not like Sea Foam. I would do a search on "Sea Foam Problems". I have used it as an additive. There is also Yahama "Ring Free", which I suspect may be a better choice as an additive.

I have never used Sea Foam as a Carb cleaner. I would be cautious.

[Captains Cat]

[416rigby]

I think Ring Free is mostly just for valves and not for keeping fuel fresh. We use Sta-Bil.

We have the same engine, a couple years newer, and had sticky carbs and clogged jets last year. A friend at work is an outboard mechanic, and he rebuilt the carbs. He was adamant about draining the carbs after each use to prevent fuel related issues, especially with ethanol, and I now do that on both main and kicker. Knock on wood...

I also keep only enough gas in it to do what I want to do, which, 99.9% of the time is a short run to the fishing area and then fire up the kicker to troll. I used to fill the tanks but now I prefer to just keep adding fresh fuel to keep things good.

Rick

[BrentB]

Do you use Ring Free in the gas?

[Roy & Dixie]

Ethanol....Interesting that all of the floats stuck in the closed position--

I thought the same thing. I might have suspected this to happen if engine had been sitting unused for a long period of time, not underway at 3500rpm for 2-3 hr 2 days earlier. All I can point to is the very short run the day before. I would not have believed it unless I was there and did all the steps I mentioned.

Several years ago, on my 1993 Yamaha 2-stroke 2 cyl (2 carbs) I would run the engine with fuel line removed until the carbs were empty and the engine would shut down. This is a 100x1 oil into gas can engine. The next time I had a chance to use the boat the engine ran so rich it kept choaking down. The float in one of the carbs had stuck to the bottom of the empty carb bowl and the fuel overflowed into the carb. After removing and cleaning the carbs I have been adding the recommended amount of Star Tron (Star Bright) enzyme fuel treatment, which was recommended by the Yahama service dept where I bought the carb cleaner. I have had no carb problems with that engine since.

I am debating doing this today: Drain the carb bowls. Mix Sea Foam and 1 gal of fuel in my empty fuel tank. Use squeeze bulb to pump mixture into carbs with drain plugs open until mixture runs out drains. Close drain plugs and pump carbs full of mixture. Let stand for a while. Drain mixture and flush fresh fuel through carbs. Run engines with fresh fuel that has recommended amt of fuel treatment from this point on.

What are the thoughts on this? Or should I simply add fuel treatment to fuel in the future?

[potter water]

My 67 VW beetle had a stuck carb float...every morning. So I kept a nice big screwdriver with a plastic handle in the engine compartment. I'd start the bug; it would stall; I'd whack the bowl twice; get in and go good for all driving the rest of the day. Next morning, whack the bowl and off I'd go. Just part of my morning start the car procedure. That went on for a couple year. Why didn't if fix it? To lazy and I had a way of dealing with the problem...also was in college and had no skills or money...except for hitting things that didn't work properly of course.