Motor not running well.

[djchris]

Ok well just as subject says.
The first day i took the boat out it seemed to run fine
Then the next time i took it out it ran great for the first half of the day, Than would not let me open the throttle up. It would just bog down and if i gave it too much it would die.
Today was the same thing.

I thought maybe i fouled plugs but i put new ones in and the same thing.

Here are the symptoms
Bogs down and dies at full throttle
half throttle runs but does not pic up speed
idles fine.

Would the gas tank being too low cause this??? There is about 1/4 tank or maybe a little less.
What should i check

It's a 86 50hp mariner

 

[CarlF]

Sounds like either the high speed jets are clogged or you have water in the fuel. Is there a clear plastic bowl inline fuel filter under the cowl? If so, check it for water.

 

[djchris]

I didn't think about water being in the gas? The first time we took it out it rained that same night and i didn't close the vent on the tank. Is there a stablelizer or de waterer that i can put it or is it just easier to drain the tank?

 

[Zum]

Those could be possibilities but are you sure it's even getting it's fuel at WOT.Did you try pumping the ball on your fuel line or seeing if it was hard?

 

[djchris]

no i did not check that. Kind of hard cause of having to steer and motor and gas tank are in the back of the boat. but i will check that later once i get it hooked up to the muffs

 

[djchris]

Ok just hooked the water hose up to it. Seems to fun fine? but motor not under load. What now?

 

[ben2go]

Sounds like either the high speed jets are clogged or you have water in the fuel. Is there a clear plastic bowl inline fuel filter under the cowl? If so, check it for water.

Those could be possibilities but are you sure it's even getting it's fuel at WOT.Did you try pumping the ball on your fuel line or seeing if it was hard?

I'm in agreement with these two.When it happens,stop the boat,shut off the engine,go to the back and pump the primer.If it's firm,it's not a fuel supply problem.Check for water and clogged jets.If it soft,there is air being sucked in some where.Check the fuel fittings,hoses,and filters if there are any.

 

[Zum]

Ok just hooked the water hose up to it. Seems to fun fine? but motor not under load. What now?

Are you using the same fuel,fuel tank and hose?
Issues like that stink,I'd go back to the lake and probably come home mad again.Still sounds like carb issues.
I'm no mechanic but I don't think your suppose to run your outboard above a certain rpm on muffs for very long.Is this true?

 

[djchris]

Well the buld does not get hard. i did not run it very hard with the muffs on but it did seem to run just fine. I have not checked the filter yet. I am a automotive tech so i am pretty handy when it comes to working on engines but i have never worked on a out board before so i hope it's nothing major cause i'm sure boat shops are expensive.

 

[ben2go]

As long as the motor isn't pushing a load(the boat) it will run fine,if its fuel line problems or possibly carb problems.

 

[Zum]

The bulb should be pretty hard,maybe have someone go with a cruise with you so he/she can steer and or squeeze the bulb when it starts to go soft or the motor starts to die.
Might even be weak fuel pump,pin hole in lines bad bulb.

 

[djchris]

This may be a stupid question but does the fuel tank have a pick up tube like a automotive fuel tank? I had a truck several years ago that had a small hole in the pickup tube so after the tank got below half it was like drinking from a straw with a hole in the side of it. Do boat tanks have this?

 

[ben2go]

This may be a stupid question but does the fuel tank have a pick up tube like a automotive fuel tank? I had a truck several years ago that had a small hole in the pickup tube so after the tank got below half it was like drinking from a straw with a hole in the side of it. Do boat tanks have this?

Yes they do and I had completely over looked this.Good call.

 

[djchris]

Well motor is running normal again. Cleaned the carbs and put a new bulb on. Got it on the water and it ran great till the bulb went flat. Removed the ball and ran hose straight to the engine and boy does it haul ***. Now my question is how fast do you think a 16ft boat with a 50hp should go with two guys around 180 pounds go???

 

[Zum]

Don' know what type of hull you have but I'm guessing...40 ish.

 

[djchris]

Well took it out today and the wind was nuts but we managed 30mph. Im figuring i can get just a bit faster on calm water.