johnson 200hp, won't idle after 2 hours of break-in.

Please help fellas. Friend got a remanufactured johnson 200hp, and we went out today to start the break-in period. It starts and idles perfectly.

We added a 50:1 mix in the tank + VRO pump as per the manual. Boy does this sucker smoke at startup.

For the first 10 minutes we ran it out of the harbor at 1500rpms, then for the next 45 minutes we kept it under 3000 varying the speed every 10 minutes. After an 1 1/2 hours, we gave it 3/4 gas to get the boat up to plane, then drop the rpms back down between 3500-4000 for the next 10-15 minutes. As we slowed down and went back to neutral, the engine sounded fine at idle, but then developed a coughing every 10 seconds or so, then slowly shut it self off after idling for maybe 1 minute. We started it up and let it idle down, again sounded like a miss or cough every 5-10 seconds, then we put it into gear and it dies. So the only way to get going is to put it in gear and give it gas to maybe 1500-2000 and it runs perfect, anything after 1200 rpms or so the engine purrrs like a kitten.

We came home, changed the water seperater filter since the gas in the boat had been sitting for 6 months, checked the plugs and it looked like every single one of them was wet with a glob of oil film on them. Is this because of the extra oil in the break-in? Anyways we think the plugs are fouling up because of so much oil running through the engine. Whats your opinion? Thanks.

Since it is just from the rebuilder's shop, take it right back and don't even touch anything on it to save the rebuilder saying you messed something up. Most likely an adjustment or a piece of dirt in a carb.