Pontoon Boat & Deck Boat Forum

Ok I need your help and This is the best place to come because you all have helped me out so much that I cannot thank you enough. But my situation is that I have a 40 hp evinrude motor and the other day I was out on the pontoon and it started spitting and sputtering on me and eventually died for good!!! But yes i got it running again. it was flooding out big time! I think the float needle was stuck. I took apart the carb and cleaned it and blew it out really good and to my suprise it fired right up and has been running since! the prob is that it runs kinda crappy. At idle speed it kinda backfires and sputters. middle speed seems fine but when I go into high speed it like bogs down, speeds up, bogs down and speeds back up etc..almost like im in stop and go traffic on my pontoon. Could this be due to the mixture setting not set right? I have this knob on the back that says slow speed left and right(see pic). What should i do? i was thinking about getting a carb rebuild kit? what is the price range of these kits? and is this what i should do? THANK YOU ALL FOR YOUR RESPONSES, DENNIS.

Man ya got to resize that pic. can't tell what it is

Ok that's the slow speed adjustment, L is lean R is rich, some of the older ones you had to adjust every time you went out slow and high speed jets.

Ohhhhhh man, Now i got myself in a mess here!!! can somone please help me! Come to find out the mixture knob was not working right because the knob was actually stripped out. So i took the knob off and turned it by hand and now the pontoon is over heating badly!!! it idles decent than revs way up and that when i shut it off. How do i adjust this thing? its a 1976 40 hp evinrude. it didnt overheat until i messed with this lean/rich knob.

You got it to lean, richen it to till it runs right, then keep turning till you hear it get to rich and go in between the two.

Lean means heat in 2 cycle, rich is cold

HandymanHerb wrote:You got it to lean, richen it to till it runs right, then keep turning till you hear it get to rich and go in between the two.

Lean means heat in 2 cycle, rich is cold

I agree. Running Lean can be the cause of over heating.

What they said...
Too lean = Hot
Too rich = Cold

Find your Happy medium, then richen it a tad more.
Better to run too rich then too lean...

it gets so hot that i cant even touch the shaft the propeller is on. and it sounds like it is frying greese back on the motor.. do you think any chance i messed it up? Thanks for all the replies. Help out so much.

I bet water pump is bad also.

are you starting it with a hose attached or in the water?

The boat is in the water...heres the whole story hopefully somone can help me...it ran fine for the first 5 times i had it out in the water and one day it started acting up and it died in the middle of the lake and when it died it started spitting and sputtering and backfiring. after i got it back to my dock we noticed it was flooding out or the float needle was sticking. gas was being pushed out the carb and it wouldnt run at all. So i took the carb apart and clean the float and lines and it fired right up. but after it fired up i was kinda back firing at low speeds and kinda missing out at high speeds. so i tried to adjust the lean/rich knob and it seemed to help and come to find out the knob wasnt even working it was stripped out. so i took the knob off and adjusted it by hand(i didnt even know what i was doing) lol..i turned the screw quite a bit. and i started it and it ran and started reving up really loud and it got really super hot and i mean boiling hot and thats where im at with it today. im going to go mess with it in the morning hopefully its just out of adjustment like you guys are saying. it never once over heated before i messed with this. thanks all, Dennis

You turned it to a LEANER setting. Thats why its burning up. and it WILL burn OUT if you dont enrichen it.
So, Turn it BACK the other way and Enrichen it.
It will then run cooler...

The water pump is another whole story, but could be broken as well.
But since you messed with that mixture setting, thats a good place to start..

So I went and tried to adjust the rich/lean knob again and no luck. I have adjusted it so far that i dont know where the means is. I just it to the rich side(counter clock wise) and it seems as if it would unscrew all the way out? I just dont know where to stop at when adjusting this knob. Is there a certain amount of turns you should set this at if i adjust it all the way in and back it out a certain number of turns? Im in a mess here! I adjusted it rich and it seemed to still get hot. Im hoping there is a factory setting on this thing. And how hard is it to change the water pump? and about how much are they? I really appreciate the help guys. thanks a million. I just want to get my boat back in the water and be able to trust it.

Ok most carbs are you run them all the way in, cuts off the fuel and back it out 3 turns, see if it will start, if not try 3 and a half turns and so on, when it starts with small adjustmens turn it lean till it get rough then slowly turn it to rich till it starts loading up and slowing down and back off a 1/4 to half turn

I think a good question here is how long have you had this motor and have you ever had the water pump changed before? Follow Herbs instructions once that is done if you have had this boat awhile and have not changed the pump then look into it in a hurry. If i remember correct a pump is to be check every couple years if not replaced. Also not to worry you but do your best to not let it get as hot as is has again. IT CAN AND WILL KILL THE MOTOR. I suggest that if Herb's fix and checking the pump does not work then get it to a mechanic. One other thing to check is the thermostat if it has not been removed already. My