25 Mercury

[Guest]

Hi,
My father had this pontoon boat sitting for almost 4 years, I went and got his boat to use for the summer, emptied out the old gas put in the new gas mix, 50:1 oil ratio.
And it barely started up, so I let it ran, trying to get everything going, afterall it'd been sitting for 4 years.
This older type model, not sure what year excatly, 84'-87' 25 horsepower Mercury motor that runs, but every time I run it almost 3/4 speed, it'd run smooth, but when I'd slow down a bit, less than half way down, it'd bogg down, like it's trying to stay running, like out of gas, for a couple of seconds then it'd die out. I'd have a hard time trying to get it started again. Playing with the choke, finally runs and it'd be fine once I keep it almost 3/4 speed or higher again, it'd be fine till I slow it down...it kills again. I've checked the gas lines, everything.
I've taken it in to a boat dealer, told them the problem so they said that they fixed it, putting in a new carbuerator kit on...they hooked up the hose to the moter and did a test run. I thought it was good as new but it did the same thing again. So I'm thinking it's different in the water, you'd have to put the pontoon in the water to see what I'm talking about. I don't know what to do. I've noticed that the primer bulb feels like there's no pressure on it when I squeezed it to make sure there was gas going through even though I had it running at 3/4 speed, I'd slow it down, it kills then I'd check to see the primer bulb feels no pressure in it, I didn't know if that was normal or not. I've made sure the gas tank, the screw cap is open on the gas cover.

What should I do? Next week I'm taking 3 families up to Leech lake and I'm trying to get the pontoon ready for the kids. Any tips, any info would be greatly appreciated!

Jiggerman

[Guest]

Thanks Valv!

I'll just a new primer bulb just to be sure...but is it supposed to be tight? Like when you first pump it the first time, it'd be running but when it quits after maybe 10 mintes of running 3/4 speed, it's all warmed up, should the bulb still be tight like now after it quits?

Yeah, there's good steady water comming out of the pee tube when it's running. Excuse me for saying this, I don't know alot about carburators, but what is varnish mean? I'll try the SeaFoam...see what happens. Thanks!
Jiggerman

[Borch]

The varnish in your fuel system occurs from leaving old gas in the system. If your going to leave any gasoline powered equipment for long periods of time 4 months or longer you should treat the gasoline with stabill or a simulair product. Sea foam is a gasoline additive that cures many ills caused by fuel. Removes water, cleans dirt and varnish from the system. Read the can for the proper mixture. As I recall you use more for marine applications. You may also want to check your fuel pump/filter as it may be clogged with dirt or varnish.

Good Luck!

[doubleUcubed]

To answer the fuel line/bulb/tank question see if you can borrow someone who has a tank and line that you know works. I had a similar problem and I went piece by piece the first time, just a lot quicker to try a complete set up that you know functions properly. Hopefully it's the gas line scenario! Good luck!

[Guest]

Thanks guys!
I'll get to it right away as soon as I get of work. Gotta get it working for next week! Thanks for the tip! I'll let you know if it works.

Jiggerman

[Guest]

Well, well, guess what? You were right, it was just a simple leak in the bulb primer! I went and bought a whole new gas line for it.

Runs great now. Smooth! Thanks for the tip!!

Jiggerman

[Valv]

You can try a new primer bulb, it could be your old one is leaking back and leaves no pressure in line.
If they rebuilt carburators, varnish should not be a problem. Does it also have good water coming from little pee tube ? That is very important, after many years water impeller gets cracked and worned out, it will not pump water and overheat motor (you know what that means... ). You can try to mix SeaFoam into gas (it's a cleaner) and run motor for few tanks to see if it improves.

[Valv]

Doesn't make you feel good when you can fix something without spending a fortune. I don't know about you, but I always celebrate when I don't have to enter a marine shop..

[Guest]

You said it Valv!

I sure feel great for a guy who doesn't know didly squat about motors and yet still be able to fix it without spending lots of money!

This Forum is great! I love it, so useful, so informative, so reliable! Sharing tips, advice, ideas is what everyone needs.

Again guys, thanks! I gotta pack some stuff, get the poles ready (adding new lines) for the trip next week! You guys rule!!

Jiggerman

[Valv]

Way to go Jiggerman, one more suggestion regarding fishing lines (but you probably know it) check your knots !!! We were fishing last week with a friend of mine, he landed his 24.5" walleye and when it got into the boat the knot at the lure untied.....He was glad fish didn't fight at boat or he would have lost it and so his new Rapala. That was the biggest walleye he got in his life.

Lesson learned in a hurry.

Have a great time !!