Merc 40hp high idle (only when warm)

[mattwarner]

Need a bit of help, I have a mid nineties Merc 40 (twin cylinder, single carb) its starts and runs perfectly but when its warm and ive opened the throttle up it seems to "stick" to high idle rpm when I slow down an go into neutral making it very clunky going back into gear.

Ive simulated this on muffs with the cover off to check its not the throttle cables and they all look fine and the cam is back as far as it goes so its not a cable adjustment issue, the linkage on the carb is spring loaded and if I put pressure with my finger the revs drop back down so its almost like the spring doesn't have enough tension??

Any help would be greatly appreciated!

[uncle al]

what revs is it ticking over at? is it tiller or remote?have you tried a drop of wd40 , has the spring come away from the end of where its located on the carb body, cables out of adjustment or sticking? When i used to set up OBMs .I set them up so from fwd to neutral the revs increased by 200rpm. Is it an ex R.N.L.I. obm with all the extra fittings?