Question about Mercury motor

[hmdomn]

I have a 2003 25 hp Mercury 2 stroke....I took it out a few days ago and it acted funny. It was fine getting to the fishing hole. After letting it sit for about 30-45 minutes, I tried to start it again. It fired, however, when I shift it into gear to give it juice, it stalls. It did this on 3-4 different times throughout the day. I noticed the primer bulb was soft one some of those times, so I primed it until it was hard again, then it fired and it stayed running after a couple pulls.
I don't know if it's a the bulb problem....it may be a coincidence that it fired up when I primed it. What do you guys think? Not enough gas? Mixture off?
It stays and idles fine, just sometimes it stalls and hesitates when I open up the throttle.

[tinmarine]

How old is the tank and bulb? Could be a bad bulb and letting the pressure release and starving the motor. You don't need much to fire the motor, but you need the pressure when it's under some load. You can actually test the bulb to see if it's good, bit of a hassle, but you can. Get some clear gas line from the tank to the bulb, pressurize and see if it bleeds back to the tank. I tested one a few years back with water and just looped it and you could see it bleed back through the supply side.

[hmdomn]

It's a 2003 hose, etc. What about the mix? If it's off would it act like that too? I had some old gas from last year and I mixed new gas in before I took it out.

[tinmarine]

It's a 2003 hose, etc. What about the mix? If it's off would it act like that too? I had some old gas from last year and I mixed new gas in before I took it out.

Depends id it's E-10 or non ethanol gas. With today's gas and stations not required to label ethanol gas, I don't use old gas. To the point that I drain my tanks in my boat. After 60 days it goes into phase seperation and for the plain fact that it absorbs moisture. How do ya like that? If you do have ethanol gas, DON'T use dry das with it or mix new gas with it. From what your describing it just sounds like a feed issue to me. Not sure if there is an anti siphon valve on that tank or not, but you can also pull the hose out and check the screen for the pick up tube. Remember if you see that the gas at the station is E-10, don't use it. It melts fiberglass tanks, been a cause to damage VRO's in Yamaha's and melt certain feul lines. All lines NEED to be alcohol rated lines or it eats the hose away from the inside.
So, check the plugs, make sure the motor is de carbed and check your tank for issues. If you prime the bulb and the issue rectifies itself, then start there.

[bigpapamike]

sounds like maybe your vent might be plugged up a little bit always check the obvious or simple stuff first.

[ENCORE]

sounds like maybe your vent might be plugged up a little bit always check the obvious or simple stuff first.

Excellent advice ! BUT, DON'T USE ANY DRY GAS in your motor. Dry gas can harm outboards. Use SeaFoam instead, which will not damage any parts on your motor and, you'll be surprised how much better it will run.
If the bulb gets soft after just that short a time, I'd replace the complete fuel line. I've seen many people just try to replace just the bulb and continue to have a problem. Then replace the lines and the problem goes away. It only takes a very tiny air leak to mess up your day. Fuel lines can collapse also, which is difficult to identify.
From what you stated, I'd go with replacement of the fuel line and add a can of SeaFoam.

[mikey]

When you guys talk about vents....are you talking about the gas tank cap? Not to throw this off the topic, but when do you vent and when do you tighten it down?

[Flash]

When you guys talk about vents....are you talking about the gas tank cap? Not to throw this off the topic, but when do you vent and when do you tighten it down?


Not sure what vents the others are referring to - but regarding the gas tank cap vent, it is opened prior to priming and running the motor, closed after trailering and during transport - at least that is how I use it.

[roundlaketom]

I have been told that all gas sold in Mi. now has ethanol in it. Stable makes a marine product that's supposed to work well. It's green as compared to the red.

[Greenbush future]

Sounds like a air issue with fuel line and perhaps the connector too. Replace the entire fuel line and motor connector, I had a connector go bad and found it's just better to do the entire fuel line all at once.