115 merc wont run well till warmed up

I have read alot of the posts and have not seen anything like my problem.
88 115 l6 merc starts and idles perfectly, will not go over 3000 rpm and has no power, almost sounds like it is flooding out until warmed up. Will idle it for about 10 minutes then shut it off for about 10 minutes. Then when started back up it will run perfectly through the day any rpm range. Unless you set for long enough for it to cool way down it will be fine. If it isnt shut off then stated it takes about 30 minutes of idling before it wants to run right.
Changed power paks, spark plugs. All the fuel system has been redone, cleaned tank, new fuel lines, rebuilt fuel pump, carbs cleaned.
Ok I havent done the pickup coil test yet but can it make the engine not run above 3000 rpm only when cold? It is a winding I would think it wouldnt work better heated up.
Seems to be backwards from other troubles I seen here.
Thanks!!!!

Re: 115 merc wont run well till warmed up

When was the last time the carbs were cleaned out? Floats adjusted?

Does it run better if you bump the choke while trying to get over th 3k? You may have to lean the carbs back just a tad to find something that works when cold and hot.

Re: 115 merc wont run well till warmed up

Check the stator with a DVA cold and hot, will just about bet its got a weak winding

Re: 115 merc wont run well till warmed up

Faztbullet said:

Check the stator with a DVA cold and hot, will just about bet its got a weak winding

Click to expand...

I6's aint my cup a tea but I'd have to go with this too.

Re: 115 merc wont run well till warmed up

Curious to know compression both cold and again warmed up, just to see if there is any serious measurable difference. If so, slug it with Sea Foam to find out if the ring lands are a little sticky, hanging up the rings while the pistons are still cool.