1983 evinrude 35hp surging part 2 please help me!!!

[dusterpylet]

Got this motor serviced, and found fuel lines on rear top of motor were capped off, the bottom line that runs out of the front of the block was tee'd into the primer so this was all fixed and put back to normal. The boat starts and idles and runs great up to about 3/4 throttle, at full power the motor runs good for about 1-2 minutes then it surges really bad, idle to wot...pumping the bulb allows the motor to run at WOT for a little bit longer but it starts to surge again. I tightened all of the fittings on the fuel lines, and at the bulb, richened my mixture setting figuring maybe its a lean situation, all to no avail. Im starting to wonder if there is a way to bypass the fuel pump, so it runs off tank pressure, maybe this is why the few lines were cut and plugged off the motor? i am thinking maybe the fuel pump is peetering out.

Has a brand new water pump, motor runs good, and telltale isnt hot, block isnt hot, so the motor is not getting hot and trying to quit.

I also rebuilt the carb myself before i took it to the shop to sort out the fuel lines...i did not adjust the float, i just put it all back together the way it came apart so i dont know if the float is out of adjustment, i do not know how to adjust the floats in the carb, if that is the problem, i am ripping my hair out over this problem, it never seems to end....


I greatly appreciate the help if you can give me, if i could i would pay for your time, that is how much this means to me, bass season is hitting around here and i really want to be out fishing.


Mike Howard

 

[bktheking]

Re: 1983 evinrude 35hp surging part 2 please help me!!!

Most small motor the float is parallel to the carb body when flipped upside down, not entirely sure about you motor. Idle and WOT are 2 different issue with the carb, sounds like its not getting the gas it requires which may mean its time for a fuel pump. Is the tank venting properly? What did you do to the carb, did you soak it for a few hours, pull the welch plugs, wash it ,blow it out and put in a new kit? As a test you could also try choking the motor when it starts this business to see if it recovers, may indicate a dirty carb.

 

[tashasdaddy]

Re: 1983 evinrude 35hp surging part 2 please help me!!!

see carb rebuild in TOP SECRET FILE.

 

[dusterpylet]

Re: 1983 evinrude 35hp surging part 2 please help me!!!

Ive heard the term "venting" a little bit, and i dont quite know if i follow it completely...It is a metal tank, and i dont know if it has a vent, it just has the fuel line plug into the top, where the gauge is, and then has a metal cap on it...when i open the fuel cap on the tank, you can hear it hiss as the vapors leave the tank? is there a vent im missing...you see i just had a problem with it dying completely after coming off plane, so i had the motor worked on for that problem...now it wont die at all unless i turn the tiller to the maximum rpm setting, then it starts surging...

 

[backyard mechanic]

Re: 1983 evinrude 35hp surging part 2 please help me!!!

If you have a 1984 engine you have a "single" hose tank and that requires that the vent (usually found in the top of the gas cap) should be open. The two line fuel tanks required the tank be pumped up/pressurized before you started the engine. The "other" hose was an air return to keep the tank pressurized and the motor running. That was a 60's thing...

That you heard a hiss noise at that vent tells me you had it closed and you are essentially starving the engine of fuel. Be REAL careful with that.... you could burn your engine up. That vent is to be open when the engine is running. Better days are ahead...

 

[dusterpylet]

Re: 1983 evinrude 35hp surging part 2 please help me!!!

Ok.. i just looked at my fuel tank, and it indeed has a little flat deal on top of the fuel cap, i tried to twist this to maybe open it, with no luck...i took the cap off the tank, which is hooked internally to the tank, and it looks like this is an integral part of the cap, which means it cant open or close. I dont know if this may be the wrong fuel tank for this motor, but before i got this motor worked on, the boat would run all day at full wide open power, the day i had the problem i had just made a 9 mile run in oroville resevoir, with no hiccup until i idled down off of plane...wide open throttle for 16 straight minutes, no problem. Im so confused with this motor at this point...


Mike