1987 Evinrude V6 175hp after rebuilt , when release accelerator engine stay high rpm

[jerry1]

Hi guys
I bought the engine death with burnout piston. this is 1987 Evinrude V6 175hp # model E175TXCDR J1143976
So I take out part by part, replace sleeve,cut block for new pistons, new bearings, new seals . Every parts replace for new . After rebuild motor from first start running nice. But when I increase rpm and
release carburettor accelerator , close gas and air . Motor holding high rpm until I kill with ignition key. When I start again with release accelerator running on low rpm.
So I thing maybe I need rebuilt carburettors and after rebuilt I have same problem. Then I replace timer base and two ignition power packs. And same problem. The motor has no more old parts to replace. Guys please help me . Any suggestion I will be appreciate you .This is very strange ,from where motor take air to running on high rpm. Though carburettors are close.
This is video with problem.

https://www.youtube.com/watch?v=DLh8kjDMJ_I

video2

https://www.youtube.com/watch?v=RkLFbtdMsAY

[Solarman]

Can't tell much of anything from video. Was trying to watch throttle plate linkage, but camera was all over the place. Check throttle plate butterflies to see if they are returning to idle position on all carbs. Can look in throat of carbs to see throttle butterflies. If they are not returning to idle position, see if springs are loose? And check that they are not sticking? If any of the butterflies are staying open, not returning to idle position, it will do this.

Good luck.

[jerry1]

Originally posted by Solarman View Post

Can't tell much of anything from video. Was trying to watch throttle plate linkage, but camera was all over the place. Check throttle plate butterflies to see if they are returning to idle position on all carbs. Can look in throat of carbs to see throttle butterflies. If they are not returning to idle position, see if springs are loose? And check that they are not sticking? If any of the butterflies are staying open, not returning to idle position, it will do this.

Good luck.

Thank you so much for your help.
The plate butterflies close very tight is no any gap between plate and throttle. I think the problem is in ignition advancing. Ignition advancing don't want return to neutral position until restarting engine. I have no idea what stops ignition advancing at high point.

[Solarman]

Ignition advancing is by the linkage from throttle. The timing coil slides with throttle linkage movement. If slide does not move easily, you may have something resisting the slide movement? Maybe wires are too tight, or something is getting in the way for it to return to idle?

In your video, you moved the timing coil/ throttle advance linkage with your hand to speed up the motor.

Post back if you find anything. Good luck.

[jerry1]

Originally posted by Solarman View Post

Ignition advancing is by the linkage from throttle. The timing coil slides with throttle linkage movement. If slide does not move easily, you may have something resisting the slide movement? Maybe wires are too tight, or something is getting in the way for it to return to idle?

In your video, you moved the timing coil/ throttle advance linkage with your hand to speed up the motor.

Post back if you find anything. Good luck.

This is very strange because this is what you said . Everything is mechanical linkage
and Timer Base return at start position, but when I look on timing with stroboscope , ignition mark it remains advancing position.
I will do better video on Sunday and I appreciate you.