carb tweaking?

[angel_guardian]

I am having a hard time adjusting my idle/mixture screws, when I first opened motor (82 merc blackmax 150) up all the carb screws were seated tight. I opened them up 1 1/2 turns per another thread advice. This was too much so set them back 1/8 turn at a time til it sounded good. At this point I ran motor on lake for half hour or so and it started to act funny again. I checked the screws and they had all rattled wide open. They were completely loose and so I had to tighten them to sitting position and start all over. Does anyone have any idea what would create this problem and how to prevent it?

 

[Chris1956]

Re: carb tweaking?

Angel, I looked up the carb for that motor and it showed all fixed jets. There was no adjustment for idle mixture, until after the 1985 model year Black Max. That begs the question "what do you have"?

 

[angel_guardian]

Re: carb tweaking?

Good question. I'll post a pic

 

[angel_guardian]

Re: carb tweaking?


Does this help?

 

[Chris1956]

Re: carb tweaking?

I did not see any carb adjustments in the picture. Looks like you are missing a cover over an idle jet on the top carb....Those covers should always be snugged down. if they are the things that rattle loose, use a drop of blue locktite.

 

[angel_guardian]

Re: carb tweaking?

Its not missing I just removed it for the pic to show what I was adjusting

 

[angel_guardian]

Re: carb tweaking?

But this now opens a whole new can of worms; if that is not an adjustment then why did it run better when adjusted? And if this is the case then what do I do now?

 

[Chris1956]

Re: carb tweaking?

Those jets should be snug in their seats. Loosening them is not adjusting them. You might check the number on them and see if they are stock jets. How was the motor running better? Running at a faster idle speed? Smoother?

 

[angel_guardian]

Re: carb tweaking?

Both faster and smoother. Before adjusting I could occasionally get up to 30 mph wot spitting and sputtering. After adjusting 45-48 mph with minimal spitting. No probs with holeshot. It would jump right up, plane out and run pretty smooth.