Hard starting issue during de-carb?

[reccrew]

I just finished the break-in on a rebuilt 2000, 175 EFI. It had NGK-BU8H plugs in it and after the double oiling for break-in they were pretty black however the engine ran flawlessly. I mixed up "Don's Cocktail" in 36 gals. of gas for my last winter trip and changed the original plugs with a new set of NGK-BU8H plugs. I have a set of NGK BPZ8HS-10 but was afraid I may foul them as the engine was pretty carboned up after break-in.
Anyway, put the boat in the lake & the engine started fine, I fast idled it at 1500 RPM for a good warm-up and got a lot of smoke. I then took it out and ran it between 4500-5500 RPM for about 5 minutes, shut it down for 20 minutes and then she started right back up and off I went for a short 2 minute run. I stayed on the trolling motor almost an hour so the engine really cooled down.

Air temp was at 39 degrees and water was at 47 deg. After that she wouldn't start at all, she just turned over but no fire. After several attempts I gave it about a 20 minute break and it finally started and ran throughout the RPM range to WOT back to the ramp 5- minutes without any issues. Once I got near the ramp. I tried 3 different short WOT runs without further issue.

My questions are: Could I have fouled those new NGK-BU8H and then the WOT run cleaned them off? I planned on running them for this tank only and then put in the BPZ8HS-10 but now, I'm concerned my de-carb isn't completed and I may foul them too? Should I gap to .040 and install these plugs or, stay with the BU8H until I burn this crud off and then change out?
Thanks!

[blackboat]

You might check your idle timing and TPS voltage to clean up the idle. Shoot for the lower half of the TPS voltage range and 7,8 degrees ATDC on idle timing,which will lean up the idle,less smoke and easier starting.This worked for mine,98 200 EFI,which was always a laughable mosquito killer at the ramp.

[reccrew]

Excellent suggestion...Thanks