[jwilkey84]

I need to know the proper way to adjust my carb on my 40 hp mariner. It is probably an 80's motor, I don't know the exact model off the top of my head. It is a 2 cylinder, 2 stroke. I have had it for 2 years and the first thing I did when I got it was clean the carb. I tried it and it seemed to run as good or better than any of my other motors, so I left it alone. As I cleaned it, I just put the needle valves where they were previously, and it was good enough for me. Well, a couple weeks ago I was out fishing and noticed that after periods of slow speed or idling, when I went to WOT it would sometimes hesitate or miss and cut out. So tonight I cleaned the carb up and put it back on, but I noticed some things about it while I was cleaning it. First, the idle (top) screw wasn't even touching the metal plate that would adjust the throttle. I think that may explain why it idles rough. Could that be a possibility? And I counted the tuns on the lower needle valve while I was cleaning it and it was backed out 4 1/2 turns. Is this normal, or close? I thought I might go to the lake tonight and mess with the valves, but I thought I would get some input and advice on how to set them before I go. Any help would be nice, Thanks. It it makes a difference, my mariner is the kind that was made in Japan. I think during that time there were some made in Japan, USA, and Canada.

[Tadd_P]

ok u took it out four and a half turns or you took it out four half turns which actually adds up to two full turns? Anyways you should run them out one and a half turns then while its running take each one back in till the motor stalls and back them back out about a 1/8 to 1/2 turn no more do them one at a time and you should be good.

[jwilkey84]

It was originally at 4 and 1/2 turns out from the needle seating. Could this be why I usually go through a couple sets of plugs in a season? Also, the top screw isn't really a needle valve it is just a screw to adjust where the throttle can be at it's lowest. So I guess ther is only one true needle valve, do I want to adjust it at idle or full speed?