1971 Evinrude 9.5 rough idle and dies when given throttle

[Jordan09]

I have a 9.5 Evinrude and have cleaned and rebuilt carb , put on a new fuel pump, took off flywheel and points and everything looks like it has been replaced, replaced spark plugs. Finally got it firing and has a very rough idle and will idle for a min and then dies, and when I try to give it throttle manually or otherwise it dies. Not sure where to go now?

 

[racerone]

Perhaps throttle plate is opening too early.-----Did you have the high speed jet out of the carburetor bowl for cleaning ?---Brass item about 5/8" long with 1/4--20 thread.

 

[Crosbyman]

what was done to clean the carb….

did you go so far as to remove the 2 round plugs and clean out the low speed circuit

the HS jet is way behind the bolt plug at the bottom of the carb


utube has 2 good videos on the 9.5 carb overall

https://www.youtube.com/watch?v=r-VTkOuSg00
https://www.youtube.com/watch?v=Y2pwU5aho9U

 

[Jordan09]

When I cleaned carb and rebuilt. I removed jet and plugs and dipped it overnight and then blew it out, new float and needle gaskets and plugs

 

[Crosbyman]

exhaust fumes leaking inside the cowl may be killing it ... does it run ok with the cowl off and fresh air ??

 

[Jordan09]

I’ve had the cowl off every time. Cleaned carb again and got it idling alright with choke on but the second I turn choke off it dies. Also put it in gear with choke on and throttled up and sounds fine just will only run with the choke on. Guess I’m not getting enough fuel for some reason?

 

[racerone]

Correct.-----Starving for fuel.-----Usually the high speed jet is plugged.----Or test run with another tank and hose.

 

[Crosbyman]

so both carb circuits are starving...ls & hs

wonder if the fuel (AKA the float) level is ok did you adjust to specs and have you tried different engine angles on the transom itselft to keep things horizontal during tests

 

[iggyw1]

Since everyone is in sync here that it is a fuel problem, just a thought here, but I would disconnect the new fuel pump from the motor where it is mounted, Leave the hoses connected to it, and pump the ball on the fuel line to see if gas leaks out of the hole on the back side of the fuel pump. If it does, your diaphram in the new pump is no good. I know you said it's a new pump, but still could be defective. With nothing to lose, check this out.

 

[Jordan09]

I messed with it yesterday and put the old fuel pump on it and ran the same. Then messed with the rich lean adjustment and put it all the way in and screwed it way out and didn’t make any difference. So I pulled the plugs two plugs out on the side and got the plastic piece out and ordered a new one 0312909 is the part number and I’m hoping that is my problem

 

[Jordan09]

I replaced the filler plug for the idle, and had it out today and just ran with choke on and noticed I have no top end power and got home and checked and adjusted points and ran it again and put it in gear and throttled up and the power is coming and going. With throttle wide open it would run for a min and the bog down and then come back on its own. I’m guessing that’s an electrical connection somewhere

 

[Crosbyman]

guessing won't work


you need to work methodically

first compression 65-70 and upwards is ok for 9.5hp


then .. electricals if coils are in doubt replace same with points condensers plug wires boot clip etc...

adjust timing properly ​

http://www.youtube.com/watch?v=ga1Cjymj6ms&feature=youtu.be

coils from China are $15 or less in US $$
https://www.ebay.com/itm/2x-Ignitio...rentrq:5409f89516d0a4b7b6f8ca31ff8f8477|iid:1


redo that carb again see post#3 above adjust float and link

just case disconnect 2 wires to the kill switch

run it with cowl off....

patience brings joy....

 

[racerone]

Find the high speed jet ( orifice plug ) that is screwed horizontally into the float chamber !----It is about 5/8" long with 1/4-20 thread.----All the fuel goes through it.----The symptoms point to a blockage there.

 

[Jordan09]

I have cleaned entire carb multiple times don’t believe that’s the problem, pulled plugs and they were black indicating poor spark or running rich. Also dropped bottom end and need new impeller but the rest of the bottom end was full of water.

 

[racerone]

checked the thermostat ?------That item is often stuck open or missing on those motors.----Replace the sparkplug wires.-----They are cheap enuff.------If you have cleaned the carburetor then as you say the problem is somewhere else.