Mercury Carburetor adjustment specs

[skimek]

I have a 1990 Ski Sanger with a Mercury 5.7l Ski inboard (250 or 260 hp) with a 4bbl Qjet. I have been putting off rebuilding the carburetor for some time (years...) and dealing with rough idle, hard starts, incorrect burn, etc. I finally had it when it was taking my wife several minutes to start it at the ramp at the start of each outing and it wasn't starting like it should even when warm.

I have already replaced and checked all of the ignition pieces, set dwell and timing resulting in very little difference.

I am now in the process of "rebuilding" the carb with a rebuild kit from the auto parts store. I have totally disassembled the unit, soaked the parts and blew out the passages. I do not expect to need to change metering rods or any of that. I did need to re-sleeve the throttle shaft, but found somebody who documented an easy way at: http://www.thirdgen.org/techboard/posts/carburetors/206860-worn-qjet-what-now/1529498-post2.html"]http://www.thirdgen.org/techboard/posts/carburetors/206860-worn-qjet-what-now/1529498-post2.html

As I started to put it back together, as I noticed on some of the other threads, the rebuild kit paperwork did not have the adjustment specs for my specific marine application. Does anybody have these adjustment specs, or am I on the hook to buy the Mercury manual for $85? Maybe somebody used a marine rebuild kit and has the spec sheet sitting around? Any help you could give me would be appreciated.

 

[skimek]

Re: Mercury Carburetor adjustment specs

I need to apologize. I just found the page to read BEFORE posting a question and it has a link to the Mercury manual. I am now downloading a several hundred MB file, so may have the information I need in a day or so.

Call me a what - a "cadet" or possibly even a space cadet!

 

[skimek]

Re: Mercury Carburetor adjustment specs

So I am done with the rebuild and although I haven't put the boat in the water, I am not happy with the idle. Even when warm (choke open) I cannot get the idle to smooth out. Smells like unburnt fuel and I can actually see a sheen on the water being pumped out the exhaust. It revs fine with no apparent unloaded hesitation.

If anybody has experience with the Qjet adjustments per the manual, I have a question; How do you perform choke rod adjustment? The Merc Manual says to make adjustment on the choke rod so that the top of the rod and the hole in the vacuum break are horizontal. This doesn't seem to be possible. The top of the choke rod is below the hole in the vacuum break and if you unbend the choke rod further, all you do is unwind the choke coil a little - it does not increase the level of the top of the rod. The choke does operate, but may be a bit slow in opening.

Any other suggestions? I was just assuming the carburetor was the problem as even though I put stabil in the fuel at the end of every season, it does sit for quite a while each year and last year didn't see the water at all. After reading some posts, I should probably check for tuliped valves, but I would think that with over 700 hours, that would have been apparent before now.