1972 Evinrude 9.5 problem!

[benvan77]

Motor only wants to run at idle to half throttle. Whenever I give it anything above half throttle it dies. Starts up on 1st-2nd pull everytime. Smooth idle. But all of this only when the choke is on. Checked spark jump, got good spark to both cylinders. Have fresh gas.

 

[Fleetwin]

Will it run OK with the hood off?

 

[benvan77]

better but not great.

 

[racerone]

Check for spark on both cylinders.---Spark that is " good " needs to jump a gap of 1/4" or more.----Those motors run very well on one cylinder.----May have cracked ignition coils.

 

[benvan77]

Spark is good checked that first. Will make intermittent sputtering some at lower idle, sounds like a mild backfire. But as soon as the lever gets past half throttle it will bog down and die.

 

[racerone]

Have the 2 coils been replaced ?---Does spark jump a gap of 1/4" or better ?----Has the high speed jet been removed for inspection / cleaning.

 

[Fleetwin]

Have the 2 coils been replaced ?---Does spark jump a gap of 1/4" or better ?----Has the high speed jet been removed for inspection / cleaning.

Good advice.

The reason I asked about the hood as those engines had a habit of eating their own exhaust. That was due to a cracked or missing exhaust tube between the mid section of the leg and the outer mid section cowling.

 

[benvan77]

K spark jumps gap of 1/4''. Do not know about coils, I have definitely never replaced them in the 4 years I have owned this motor. (mind you before now this motor ran flawlessly.)
Have not removed the high speed jet. Is this the jet in the lower unit of Carb? If so what is the best way to access this jet for removal, or can I clean without total dissasembly?

 

[benvan77]

Important addition all of this only when the motor has the choke engaged. With choke disengaged runs and immediately dies.

 

[racerone]

It seems you are adding little clues on each post.---That does not make it easy for anyone to help you.-Sorry.

 

[benvan77]

My apologies certainly not trying to be anymore confusing. I updated original post to include all of the pertinent info. I did leave my responses to the questions you guys have asked in sequence so that everything was easily read.

 

[kbait]

Perhaps you have a partially obstructed main jet. It's directly behind the carb bowl drain plug (aiming toward front of motor). Remove drain plug and probe straight back w/thin wire and re-test.

Good luck!

 

[benvan77]

k thank you. Should the small hole front toward the front of the motor, where the drain screw is at be open? I see the threads of the drain screw here blocking that hole, is this normal?

 

[Fleetwin]

Important addition all of this only when the motor has the choke engaged. With choke disengaged runs and immediately dies.

That's your clue that the carb is all clogged up. Time for a complete carb overhaul.