rough idle....help

[Dawgs]

ok heres what i have..1987 150..vro removed and 2 old style fuel pumps installed..i have pre mix in the tank..i rebuilt the carbs myself and im not mechanic....i just replaced the crankshaft..motor starts up and runs on muffs...it idles rough...its also idling at about 1100 rpm(i know too high)...i have spark in all 6 cylinders...all the carb flaps are closed...when i pump the bulb it never gets REALLY hard..and fuel runs out from the carbs..

can it be floats set wrong? would that make it idle that rough? plugs all look wet with fuel/oil

 

[Daviet]

Re: rough idle....help

If you have fuel running out of the carbs, the needles are not seating properly, could be float setting or something under the needle valve. Yes it will cause the engine to idle rough and foul the plugs.

 

[hidef]

Re: rough idle....help

If the floats aren't adjusted right they could cause the problems mentioned. Once the carb bowls fill up and the float closes the valve that primer bulb should get firm.

 

[Monte1961]

Re: rough idle....help

answered

 

[Dawgs]

Re: rough idle....help

ok i pulled the carbs...ill open them up and reset the floats tomorrow. any tips? so the bulb should get REAL hard when pumped?

 

[Dawgs]

Re: rough idle....help

and let me ask this.....is there any way the carb can be tested before its reinstalled on the motor to find out if the floats are set correctly? can a fuel line be hooked up than pumped to see if the needle seats correctly?

 

[Daviet]

Re: rough idle....help

You can hold the carb in the upright position and blow into the fuel inlet with your mouth, you should be able to blow air through it. Now turn the carb upside down and repeat, you should not be able to blow through it. Do not used compressed air for this, to much pressure.
This will tell you if the needle and seat is capable of shutting off the fuel flow.

 

[Dawgs]

Re: rough idle....help

daviet...by doing that it will tell me if the float setting is correct?

 

[Dawgs]

Re: rough idle....help

ok i opened up the carbs...i reset all the floats and discovered that the middle carb had a problem...the needle disconnected from the wire clip that holds it to the float. hopefully thats my problem...ill let you know

 

[Dawgs]

Re: rough idle....help

well i put the carbs back on..put in new plugs...i did not put the plate over ther carbs yet...same thing...motor gives me a hard time starting then idles rough....seems a little better but still rough...


now what?

 

[Dawgs]

Re: rough idle....help

here are pics of the plugs in order......can we tell by the plugs whats going on?

 

[Dawgs]

Re: rough idle....help

they were brand new and it only ran for like 5 minutes. middle plugs seem cleaner than the rest

# 1 plug was black and dry....2,5 and 6 were black and wet

 

[hidef]

Re: rough idle....help

Did you pull the low speed jets? When you reinstalled did you get them back to where they were before you started.

 

[Dawgs]

Re: rough idle....help

i reinstalled them but wasnt aware they had to be set at a certain position...how do i fix this? the face plate is off so it would be easy to get to the low speed jets

 

[hidef]

Re: rough idle....help

Looking at plug #2 that one looks the best to me. So I would screw that one all the way in counting the turns and then take it back out the same amount. Do not force it when you screw it in or you will damage the jet. You just want to bottom it out not tightened it. Then I would set all the other low speed needles the same. That will most likely get you ball park. If she will start and run then you need to start adjusting until she idles down and runs right. As you lean it out she will start to sneeze you want to back off all of the low speed jets between 1/8 and a 1/4 turn until she idles smoothly. You will want to do this in the water with the boat tied to dock with the outboard in gear. Once you think you have it you need to take her out on the water and see if she will run and come back to a nice idle.

The service manual has the detailed instructions for setting the carbs and it will be a pain in the rear. Good luck

 

[Dawgs]

Re: rough idle....help

ok maybe im thinking of something different...where are the low speed needles?

 

[Dawgs]

Re: rough idle....help

where is it in this diagram?

http://www.marineengine.com/parts/j...XCUR&manufacturer=Evinrude&section=Carburetor

 

[hidef]

Re: rough idle....help

#5 is the low speed jet and on your model they are fixed. You need to adjust your idle most like a sync & link is required do you have the OMC Service Manual?

 

[Dawgs]

Re: rough idle....help

i have a seloc manual but its hard to understand a little

 

[Dawgs]

Re: rough idle....help

direction arent real clear on link and sync