1973 Merc inline 6 Kills when put in gear.

[happychef]

The motor will pop right off out of the water, or even in the water, but as soon as it goes into gear, it bogs out and dies. I found the shift cable out of adjustment, fixed that, but it still does the same thing. I have checked for spark on all cylinders, the carbs were just rebuilt last fall, I also adjusted the idle air screws.

I am at a loss. I always have done all of my own mechanical work, but this time it may have to go to the shop. Anyone have any idea what this may be?

And, for any of you who have had experience with a situation like this, how much do you think I can expect to spend for this? I assume it is something very simple that I am over-looking, but hell, I am lost at this point. :facepalm:

 

[Chris1956]

Re: 1973 Merc inline 6 Kills when put in gear.

It is very likely you set the idle mixture screws too lean. That motor needs settings as rich as possible to have smooth acceleration. Warm her up on the water, and in gear if possible, at idle, open the top screw 1/8 turn and try to accelerate. Repeat with mid screw and them bottom screw, testing acceleration each time. Repeat as necessary. The top carb will end up being a bit richer than the mid carb which will be a bit richer than the lower carb.

A shop may not be experienced on your motor, and that will cost you $$. They may want to rebuild carbs, ign etc, when all you need is a 10 min adjustment.

 

[CWKboat]

Re: 1973 Merc inline 6 Kills when put in gear.

Like Chris1956 said, it's most likely a lean condition with the carbs if it stumbles like that.

You can dial it in as noted; or I have found that a good setting for idle and acceleration is at least 2 1/4 CCW turns out from a lightly seated position on all 3 carbs. I think if you will set it there prior to going out on the lake, you will find that it will accelerate well and then you can fine tune on the lake if you need to from there.

 

[happychef]

Re: 1973 Merc inline 6 Kills when put in gear.

Thanks guys! I will try this tomorrow. Frustrating. It wouldn't seem that a lean condition would cause the motor to be so finicky, but then again, I am used to wrenching on cars, not boats.