Good Evening,
I have a newish to me (I've had the engine for a number of years but only ran in a little bit before it being put up in storage) Mariner 75 4 cylinder. When I got the engine I had to replace pretty much every electrical component other then the coils. I also rebuilt the carbs and had to install new bleeders. I never got it running really well before I put it away.
So here we are today. I did pull the carbs opened them up and sprayed them down and used some compressed air to make sure they were clean (none of the gasket stuck!). I just went thought he timing and sync procedure (I have the Merc service manual), everything needed to be tweaked a bit but it's all in spec now. After fussing with the carbs a bunch (initial 1 1/2 turns from seated) I finally got it so idles pretty well (all the old Mercs I've been around are a bit lumpy on the low end) and finally runs well at from 2500-4000 RPM, which is where I was having most of my issues. Up until about 4k is just didn't run right, kind of missing/not running smooth, 4k up to 5500 is great.
Turns out I had to lean out that bottom carb quite a bit. The top carb is about 1 3/4s turns from seated, the bottom one is a hair over a turn from seated, maybe 1 1/8 at most.
Is it normal to have that much difference between carbs?
I know I've read the engines like to be a tad rich, if I turn out that bottom screw any more that mid-range just goes to pot. Slow acceleration decent, it's not silky smooth but it doesn't ever fall on it's face, fast acceleration is good, no hesitation at all.
Is it fine, am I just being paranoid?
Thanks,
K
I have a newish to me (I've had the engine for a number of years but only ran in a little bit before it being put up in storage) Mariner 75 4 cylinder. When I got the engine I had to replace pretty much every electrical component other then the coils. I also rebuilt the carbs and had to install new bleeders. I never got it running really well before I put it away.
So here we are today. I did pull the carbs opened them up and sprayed them down and used some compressed air to make sure they were clean (none of the gasket stuck!). I just went thought he timing and sync procedure (I have the Merc service manual), everything needed to be tweaked a bit but it's all in spec now. After fussing with the carbs a bunch (initial 1 1/2 turns from seated) I finally got it so idles pretty well (all the old Mercs I've been around are a bit lumpy on the low end) and finally runs well at from 2500-4000 RPM, which is where I was having most of my issues. Up until about 4k is just didn't run right, kind of missing/not running smooth, 4k up to 5500 is great.
Turns out I had to lean out that bottom carb quite a bit. The top carb is about 1 3/4s turns from seated, the bottom one is a hair over a turn from seated, maybe 1 1/8 at most.
Is it normal to have that much difference between carbs?
I know I've read the engines like to be a tad rich, if I turn out that bottom screw any more that mid-range just goes to pot. Slow acceleration decent, it's not silky smooth but it doesn't ever fall on it's face, fast acceleration is good, no hesitation at all.
Is it fine, am I just being paranoid?
Thanks,
K