Mercury 5hp two-stroke hard to start when warm- brand new carb, plug, coil

[SAABologist]

Thank you in advance for your patience with this question you probably have heard before. This is my first post to the forum, but I have been doing some searching for answers. Here goes:

- 5hp two-stroke from 1999, running 50:1 new premium grade gas
- Brand new carburetor, the whole thing, not a rebuild with kit.
- Brand new coil
- New plug
- Cleaned all visible corrosion from stator, inside of flywheel, the magnet on side of flywheel
- Checked compression (engine cold) and it was 110

- The motor starts great when cold, I set air/fuel (about 41/4 turns) until runs smooth, set idle. From dead cold it will start after 1 pull with choke and 1-2 pulls. I have done this numerous times....
- Runs at idle for a long time, seems great.
- PROBLEM-- If it stalls on its own, or runs until I turn it off, once this motor is warm it is really hard to start. Most of the time I have to wait until it is cold again.
- Then this frustrating cycle repeats itself!

Thanks millions for sharing your advice and experience to get me out of this groundhog-day scenario!

 

[fastjeff]

..."bout 41/4 turns"

Is that a misprint! Should be around 1 1/2 turns.

Jeff

 

[SAABologist]

..."bout 41/4 turns"

Is that a misprint! Should be around 1 1/2 turns.

Jeff

I just walked out to check. It was 4 turns. Started right up. I turned in the screw to 2 1/2 turns and it ran well for about 3 minutes and died. Now it doesn't want to start even when I back out the screw to 4 turns again. This is why I am scratching my head over this, I've gone through this same procedure quite a few times.