[Jaybird244]

Hi folks,I'm new to the forum. I have a 40hp. Mariner, 1987. It's been sitting up, but I put fresh tank of gas on it. The boat will start great and idle good. With the muffs, it will take the gas opening up the throttle. On the lake, it will not take the load of pushing the boat up on top. It bogs down. I've searched the forum and found a similar problem. The suggestion was water in the tank. I do know that it did rain on the tank, but the vent was closed. I know very little, but any info. is appreciated. Thanks.Jaybird244

[Elmer Fudge]

It could be that your carbs needs cleaning.The tank must to be properly vented during operation.Make sure that the bulb stays firm after priming,if it's not,then check for air leaks in the fuel lines.

[oregonfish]

Hey Jay,I have the same motor only mine is a 1985. I had a similar problem when I first got it pushing a 15' tri-hull. Is your prop the right size/pitch. Have you tried trimming up? I trimmed up (manually)1 notch, and it pushed it a ton better, and got on plane nicely. I'm pretty new at all of this, but thought I'd put in my 2cents.Chris

[phatmanmike]

check that you are runnnig on both cylinders fully.replace your water pump(trust me)clean your carb(s)honestly sounds like a fuel starvation issue.just my 2 cents

[Jaybird244]

Thank you fellas. It is in the shop. I'm afraid that I'd mess it up. How long does it take to do the carbs?

[geofthro]

One with a little knowledge acouple of hours,Then depending on who you took it too and how busy they are?