1972 evinrude 65 hp electric shift wont accelerate

[forest65]

starts up and idles just perfect. when pushing the throttle down it picks up speed maybe up to half way then starts bogging and evens out and runs just at a very low speed compared to what it should be running at full throttle once in a while gets a little burst like it got a bit of power for a second but bogs down again. it ran perfectly fine then all of the sudden started having this problem one day. since then i have replaced the lower end gear case which was successful and took the carbs out and cleaned them up which didn't need much if any they were almost spotless inside. reassembled and adjusted the needle valves to get motor to start and run. same problem persisted. wondering what to do next and is there a possibility changing the gearcase i could have done something to make it not run right like mess up the timing. anything helps

 

[coolbri70]

Re: 1972 evinrude 65 hp electric shift wont accelerate

timing linkage fuel pump:noidea: maybe loosing spark, dropping cylinder

 

[forest65]

Re: 1972 evinrude 65 hp electric shift wont accelerate

i ran a compression test all cylinders were pretty good and i was getting spark on all 3. shouldve mentioned. what do you mean by timing linkage?

 

[coolbri70]

Re: 1972 evinrude 65 hp electric shift wont accelerate

i ran a compression test all cylinders were pretty good and i was getting spark on all 3. shouldve mentioned. what do you mean by timing linkage?

the spark advance linkage that turns the timing base when you throttle up has a ball socket that falls out when it gets worn

 

[F_R]

Re: 1972 evinrude 65 hp electric shift wont accelerate

By the description, it probably is not running on all 3 cylinders. Each cylinder has independent spark, carburetor, and compression. It needs all 3. PLUS, those motors have an inherent problem with getting water into a cylinder (or two). You have to make sure that is not the case because it will totally destroy the powerhead.

Back to the timing, there is a vertical throttle shaft that moves the spark advance/timing plate as you move the throttle. That must happen. If it sticks, it will open the carburetors without first advancing the spark, and it will bog badly, probably even conk out.

 

[forest65]

Re: 1972 evinrude 65 hp electric shift wont accelerate

how would i tell if its not running on all 3? they all have good compression. How would i be able to tell if water is getting into the cylinder?

 

[racerone]

Re: 1972 evinrude 65 hp electric shift wont accelerate

The term " good compression " means very little to some folks.---Post actual values.------Run with a timing light hooked up and see how spark behaves as you throttle up.-Test all 3 this way.---Look into throttle bores as you speed up and compare amount of fuel coming up the main jets.-----Have you tried opening low speed mixture needles 1/4 turn to see what happens?

 

[forest65]

Re: 1972 evinrude 65 hp electric shift wont accelerate

the ball joints were good on the spark advance timing linkage

 

[forest65]

Re: 1972 evinrude 65 hp electric shift wont accelerate

i forget the numbers i will go do again. and i have played quite a bit with low speed mixture needles by closing them and then opening them in 1/4 turn increments able to get it to run faster at a top speed not as smooth but definitely faster but it would die when i would take the throttle all the way down to where it should idle

 

[racerone]

Re: 1972 evinrude 65 hp electric shift wont accelerate

Have you checked the flywheel key ?

 

[forest65]

Re: 1972 evinrude 65 hp electric shift wont accelerate

sorry im not familiar with the flywheel key? where would i find it