Classic 50 mystery

[lakertaker]

Hey all, this forum is the best resource around it's helped immensely. On to my issue. I have a 87 merc classic 50 that has really got me stumped. It seems to run great when I have it on the muffs and in the water, up until I cruise to a fishing spot, bring it off plane to troll. After the slow down it stumbles and stalls. I can get it back up and running, and with a little help from the idler lever, back into gear (trying to be kind to my lower unit of course). It seems to be drowning with gas at this point. Once I get it back above 1500 rpms it runs decent enough to get back to the dock but stalls again at idle speed. I get it home to work on it and it runs great again (no flooding issues on muffs or tank). Here's what I've done to try to correct the problem
new fuel lines, new gas (50:1) fuel filter.
both carbs rebuilt twice (new gaskets, soaked overnight, squeaky clean) mixture needle 1 1/4 turns from seated.
new plugs, new switchbox (recommended by marina).
Any ideas on what to try next would be greatly appreciated.

 

[tashasdaddy]

Re: Classic 50 mystery

#1 you can do true set up on muffs, there is no backpressure on the exhaust. sounds like you need to fine tune your idle mix, while in the water. or your float needle valve is not closing all the way.

 

[lakertaker]

Re: Classic 50 mystery

I think I found the problem.... It looks like a part in the linkage was a bit loose and sticking the carbs open (above carb #1). I'll try a link sync from here, and let you know how it goes after a trip out...