Nissan NSF6A2S 3R4-1 Stalls out when trolling

[ICamel]

Last week while fishing my Nissan NSF6A2S 3R4-1(2005 Model Year) stalled out when trolling. It would not restart. After getting off the water I pulled the spark plug(NGK DCPR6E) and found the ground electrode, center electrode and tip to be completely black. I bought a new spark plug and installed it. The next day after running the engine for less than 15 minutes it stalled out again. I pulled the spark plug and it look identical(black) to the first plug. I also observed while the motor was running that the water peeing out was of sporadic flow and sometimes emitted steam.
I recognize that the spark plug is indicative of running rich, but the motor ran fine on Tuesday with the problems manifesting on Wednesday and Thursday. I only run non-ethanol gasoline in the outboard.
Ideas to look at first?

 

[pvanv]

Looks like 2 different issues, although you are noticing them at the same time.

Assuming that you always run the carb dry at the end of each and every day (to reduce varnishing), and you are not getting water or ethanol problems, your carb is likely OK. If that's the case, and the choke is not partially closed, your plug fouling is probably from oil -- especially if the plug deposits look greasy. Verify that the oil level is between the hash marks on the dipstick.You must screw the stick in to get the proper level reading; if you read the level by inserting the stick (but not screwing it down), you will be way overfilled even with a good reading on the stick. The MFS 4/5/6 A is very sensitive to overfilled oil. It only holds a total of about 3/4 pint to get to the middle of the stick.

If you are getting steam from the telltale, you are not getting enough cooling. If the water pump has not been serviced lately, it would be a good idea to install a new water pump kit -- the complete kit, not just the impeller.

 

[ICamel]

Paul:
Your diagnosis was "spot on". Too much oil in the reservoir. I drained the oil and put in fresh Honda Outboard 10-30 and made sure that it only came up half way between the hash marks on the stick when screwed in fully. It started up and ran just fine. Water output from the water pump ran normally. Thank you very much!

Mel