1983 25 hp. coughs/spits and sputters when cold

Hello all..I'm new to this forum and was wondering if you all could help..
This engine coughs bad when it's cold..I've rebuilt the carb, which was in dire need, and this year just out of curiosity i replaced the head cover gasket and the exhaust manifold gaskets. The head ports were totally, except for a hole the size of a pencil point, totally blocked shut with carbon. So i cleaned all that out, even polished the exhaust ports and channels, put it back together and it ran great. Now all of a sudden it's coughing again when it's cold (it was doing that prior to the above work, that's why i did it)..any ideas or solutions would be greatly appreciated.. Thanks rudedog24

a sneeze means its running lean, open the idle jet some and see what happens. Did you remove the lower unit and clean/inspect the exhaust tube

Hi beckerjs---i did not remove the lower unit and clean or inspect the exhaust tube..Not quite sure what your talkin' about..I had the lower unit off last year to replace the water pump but i am not sure where the exhaust tube is that your talking about. As for idle jet, i'm not quite sure what your talkin' about there either...If i remember correctly there is only 1 adjustment screw on this carb.. Is that what your talking about when you say idle jet? I noticed that exhaust comes out from the middle of the prop and about half way up the back of the motor where it looks like water and exhaust come out..(bunch of little holes in the housing)..Does that make sense to ya? Thanks rudedog

There is an idle adjustment screw on that carb. It's a slotted, brass (as I recall) screw in a hole.

The exhaust tube (usually called a "tuner") is just below the power head. It would have to come off to be inspected.

Jeff