Mercury 9.9 Hurting my Season: Advice Needed

kloudie1 · Aug 25, 2015

Wow.. We who sail at sea level wouldn't have picked up on that as a possible, Walt.. Could well be a vapor pressure problem where a bubble is developing in the high spot/low velocity section in the line, because of sun heat. If ya buy fuel at lower altitude and bring it up, that might make it worse. The folks that make gasoline use cheap fillers like Butane and propane in the blends and while octane does not change vapor pressure a whole lot with heat, the cheap filler stuff does and could well cause a problem at altitude in a line heated to 100F or so by the sun.

Zed · Aug 25, 2015

Sock Puppet said:
These motor issues are impacting the wife's confidence. She didn't want to sail yesterday when the wind picked up because we couldn't count on the motor.

Your wife is right. If you don't have a functioning MOTOR, you shouldn't be out there. Too many things can happen where you need to be on land or at your slip with a certain speed.

Wind is fickle and it won't help you when you need it most. It doesn't care about your needs, only its own(whatever they might be).

Bob 04 H260 · Aug 26, 2015

I think the tank you are using is an Attwood ? Have a look at this link maybe this is the problem, http://www.attwoodmarine.com/prevent-engine-flooding-with-fuel-demand-valve

Another point, I notice the primer bulb is pointed down. I think Mercury advises to keep the bulb vertical with the arrow on the bulb pointed up. This helps the check valve function and reduces the chance that fuel will not backflow into the tank when the engine is not running. It does make a noticeable difference, priming only takes 3 squeezes of the bulb.

With your tank plumbed into the lazarrette like that do you fill it in situ ? If so all the gasoline vapours in the empty tank are displaced into your bilge ?

I sailed a Mac26S for a few years, enjoyed it very much. I have some pictures of my mods in an album in my profile on this site.

Good luck, Bob

Zed · Aug 26, 2015

Sock Puppet said:
Zed, if you have any ideas on how to fix my motor problem I'd love to hear them.

I wish I was a motor repair guy. I'm not. I took my honda to a honda repair professional.

I just know that getting stuck 2.5 miles from land in calm sea for 3 hours with night approaching and eventually having to be rescued by the coast guard WAS NOT FUN. As a consequence, I won't go out without back up, and in my case that meant two different electric motor systems to back up the gas one. And in addition, I only run ethanol free gas, and Blue Marine Stabil in the engine.

In your case, I would move the tank out of where you have it since, gasoline vapors are heavier than air and you have no blower to vent them out of the compartment. But you also may have too far a distance for the gas to travel to the tank. I would put the tank next to the battery, and if necessary get a 3 gallon tank which is probably good for 3 hours of travel, and make the length of hose much shorter. There is a limit to how far the pump in your engine can suck gas, and thus a greater possibility for pockets of air to be in the line. But even so, your float bowl should run at least 4 minutes after you pull the gas line. When I close mine down, I pull the gas line and let it run to nothing. On my 5 HP Honda, this takes 8-10 minutes.

Other than that, I'm just saying that if you don't have a reliable unit, then you have four choices:

1. Stop sailing
2. Buy a new unit that works
3. Pay an expert to fix your unit now, and make sure he understands your whole system.
4. #'s 2 or 3, and buy a back up like a Torqeedo.

I chose options 3 & 4. But if it still doesn't work when I have to trek 5.5 miles back to the trailer in three weeks, the I may have to choose option 2 instead of 3. Nobody said sailing was cheap. And I'm a pretty cheap guy who makes everything himself if necessary, and buys at the hardware store if possible, not the Marine Store.

After all we are out in a place that is not our native environment, and the environment is basically "out to get us". Wind, waves, current, water temperature, don't care about our personal welfare.

Zed · Aug 27, 2015

Sock Puppet said:
1: As noted, I run ethanol free gas. I also use marine Stabil and Seafoam.

2: I do have a blower to vent any fumes out of the compartment, you just can't see it in the pics. This is also a ventless tank and I've never had any fume issues.

3: My batteries are under the galley so moving the tank there isn't an option. The run from tank to motor is only about 3 feet. My boat is a 1994 and the fuel tank was always located in the same area (but further to starboard so the distance was greater) I moved it more to the center to get it closer to the motor. If it worked there for 20 years with the previous motor I see no reason it shouldn't work now. I don't believe ~3 ft. is too great a distance. The only other real option for a tank location is in the cockpit, which I am not wild about but not totally opposed to. You're right, it runs about 4 minutes or so on high-idle once I pull the fuel line, which I always do when finished.

Maybe it time to buy a new engine... I know.... awful suggestion. Sometimes its your only option.

Zed · Aug 30, 2015

You will get back to us, when you figure it out, RIGHT?

MattM83 · Aug 30, 2015

i have the same motor as you and had same problem except mines an 8hp 2012 which is the backup to my volvo diesel. one of my connectors was pulling a small amount of air in which led to stalling. id fiddle with the hoses re prime and it would start up. i changed all the gear clamps and doubled with stainless injector clamps and its been running smooth for 2 years now. the motor has to draw a vacume aswell which is different pressure on the quick release than the positive pressure from the bulb could be an o ring thats worn.

eagargary · Sep 17, 2015

Sock Puppet said:
I've been chasing an issue with my 2009 Mercury 9.9 4 Stroke since last year. Sometimes it will run perfectly, other times it will run for various lengths of time and 'run out of fuel'; die. I always disconnect the fuel and run it empty when done for the day. My non-venting Atwood fuel tank sits inside the rear compartment, and the hose runs through a bulkhead fitting and to the motor.

Last season I installed a brand new fuel tank and Atwood hose kit so everything was new to the motor. Still had problems. I originally had the fuel bulb mounted perfectly horizontal, and on the advice of this forum I re-routed it to sit at an angle (I've tried angling in both directions). This made no difference. I moved the bulb from inside the locker to the motor well so I could pump it to keep the motor running when it started to die. I drained the fuel with ethanol out of the tank, checked the tube and 'check ball' in the tank, and refilled with brand new ethanol free gas.

I found the lining inside the gray Atwood hose was separating from the hose, so I thought this was restricting fuel supply. I replaced all the fuel line with fuel injection line. I replaced the bulb. I replaced the bulkhead fitting.

A couple of weeks ago it was having issues immediately, and I traced it to an air leak at the fuel hose fitting at the engine. Bingo, right! I replaced the fitting last week and the motor ran perfectly during our outing; even during a storm while we motored back in under load. We went out yesterday, motored for about 25 minutes as there was no wind...then it died suddenly. Pumped the bulb, restarted, and had to 'nurse' it the rest of the day by periodically pumping the bulb.

Checked the fuel level and it is down to about 2.5 gallons (6 gallon tank). My only thought at this point is that the tank sits below the motor fuel inlet, and with lower fuel levels it does not maintain flow, but I don't know.

Below are pics of my installation. I'm open to any/all suggestions. These motor issues are impacting the wife's confidence. She didn't want to sail yesterday when the wind picked up because we couldn't count on the motor (my slip cannot be sailed into). Please help!

I noticed that your primer bulb is up by the motor.My new Mercury 9.9 has the bulb about 3 feet from the tank if that and the longest part of the hose is after the bulb. I checked several Merc engines and all the bulbs are close to the tank,hope this helps

Bob 04 H260 · Sep 17, 2015

Another point to consider. A friend had a similar problem with a Johnson engine. He eventually brought it into a dealer. He was told it was the fuel connector. He had already replaced it twice himself. It turned out the connectors he was buying were made in China and only lasted a short time before leaking air. Since the dealer replaced them he has had no more problems.

Bob

justsomeguy · Sep 17, 2015

Yep, air leak.

agprice22 · Sep 17, 2015

Yeah. I have had this. One time, it was a kink in the hose. The other time, it was the connector at the motor. A worn ring was letting air in and gas out. Easy fix both times. PO had installed a little filter on the gas line that was kinking the hose, and he had shortened the hose too much. A new hose fixed that one. A new connector fixed the other one.

I wish you a quick fix!

Thanks,

Andrew

LittleCreek · Sep 19, 2015

jibes138 said:
I was having trouble where my 20HP Yamaha seemed to be starving for gas at wide open throttle, it would periodically skip. I mounted my squeeze bulb so it is vertical and haven't had further issues. Also make sure the flow direction on your bulb is going in the direction of the arrow. If it is backwards it will run for a while then starve the engine. Read the following: " Orientation

It is also advantageous if the primer bulb can be position in such a way that during priming it can be oriented vertically, with the direction arrow pointing skywards. This will allow gravity and the weight of the fuel inside the primer bulb to help with the operation of the one-way valves. If the primer bulb is oriented with the flow arrow pointing downward, gravity and the weight of the fuel in the line above the inlet check valve may spoil its operation, and the primer will not work properly.

This subtle but important point—orienting the primer bulb skyward—is often overlooked in many installation, but it really helps the primer bulb to do its job. This trick was shown to me by an experienced Mercury outboard mechanic, after I complained that the new primer bulbs he had installed did not work well. The difference in results is amazing, and just by changing the orientation of the primer to vertical, its operation is much improved. In just a few squeezes it should be possible to fill the bulb with fuel."
http://continuouswave.com/whaler/reference/primer.html

Thanks for sharing the link. I have been wondering why people have been having so many issues. My primer bulb is not orientated correctly either, but my 8 HP Tohatsu runs fine. My tank does pressurize after a 30 minute run, so I crack open the cap for a few seconds to relieve the pressure. I never gave it much thought until now.

I am going over to the boat this morning, and will try orientating the bulb correctly to see what happens.