86 Merc 60 horse, cannot get under 2000 rpm!

[danalex]

New carbs got here today, I pulled off the old ones and put the new ones on, new gaskets.
Same problem. Idle too high. I checked the throttle and it needed adjustment, had the butterflies open a little. With butterflies closed still idles too high. Carbs out of tune, I adjusted the idle screws, ran smoother, still 2000 rpm. The spark advance is against the stop - the wiring harness from the trigger to the switchbox hits the mount for the stator. I pulled the flywheel off to look at the trigger movement. With the throttle arm attached I hit the stop in the Clockwise direction. I have about 1 inch extra space in the advance direction. (Counter clockwise). I think if I could retard the spark another few degrees it might slow down the motor. Before I do something as drastic as working on it with the dremel, could the reeds cause this problem? I thought reeds would have other symptoms - fuel spray from the carbs and so on. I don't have anything like that.

 

[danalex]

I checked the plugs after running. Top plug black and wet and warm. Middle plug black, wet, and has crusty deposits reaching from the outside ring almost to the electrode. Bottom plug wet, shiny, warm, a little black on part of the ring.

 

[danalex]

I went out with the timing light. Set .464 on the flywheel to the pointer. Checked timing. #1 plug fires at around 13 degrees btdc. Manual says 7 - 9 degrees btdc. So it needs to fire later, that is, I need to retard the timing. (That is kinda thinking out loud, feel free to contribute, I need the input). But I cannot retard the timing, the trigger is at its max travel and the wiring harness is hitting the bolt housing the stator is screwed into. Not hitting the bolt, hitting where the bolt threads into. I am debating taking my dremel and removing enough of the bolt housing and wiring harness protector(plastic) to allow another 1/4 inch of travel, which might be enough to get pickup timing in spec. Probably have to remove some on the plastic adjustment connector of the trigger as well, it has about 3/16 inch clearance. Does anyone have any idea of a different method? A failed part that could cause this? How did this motor ever run correctly with this problem?

 

[danalex]

I took the trigger off to modify it, examined it. There is a wire corroded in two where it comes out of the plastic trigger housing. Ordered a trigger. The saga continues.

 

[danalex]

Awesomeness! Installed the new trigger, still had the same problems, checked firing order and found #2and #3 coils were swapped. Fixed that, motor started, I have it idling at 600 - 800 rpm now. Fixed. Running. Thanks to everyone who contributed, it was an unusual situation and I learned a LOT working on this motor. Possible bad switchbox as well, I swapped that out at the same time as the trigger since it was firing twice during one cycle according to the timing light. I also cut out part of the trigger so it had 1/2 inch more clockwise movement, now I have extra room to retard the spark if I need it. Again, Thanks to all! Hope someone else can benefit from this massive post.