Remanufactured Johnson 200hp won't idle after 2 hours break-in - The Hull Truth

starboard enterprise · 03-19-2007, 09:09 PM

So my 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.

A1 Outboard · 03-20-2007, 01:59 AM

Please give us some more info such as what model number is the motor? We need to know whether it is a looper block or a crossflow block and what year? When you say remanufactured, was it a factory remanufactured powerhead assembly purchased thru an authorized dealer or someone who took the engine apart and replaced a piston or two? Were the carbs rebuilt and the "VRO" pump replaced at the same time?

starboard enterprise · 03-20-2007, 02:13 AM

Hi its a remanufactured 2000 Johnson Ocean Pro 25" shaft 90 degree V6 200hp engine from Ellis Marine Outboards. It looks brand new, I think the whole powerhead was rebuilt to OEM specs, all carbs are rebuilt, and bottom end rebuilt. I'm not sure if the VRO pump was replaced or not.

A1 Outboard · 03-20-2007, 08:40 AM

The coughing that you describe is most likely a lean condition and the motor is backfiring inside the crankcase. Most of the time it is due to a carburetor problem, idle needle adustment, linkage holding a throttle plate open slightly, a vacuum leak in the crankcase or intake manifold, etc. Thermostats that do not allow a motor to come up to operating temperature can do the same thing.

Take it back to the mechanic. That break in procedure you describe is overkill. Read the owners manual for the correct version.

starboard enterprise · 03-20-2007, 01:35 PM

Quote:

A1 Outboard - 3/20/2007 7:40 AM

The coughing that you describe is most likely a lean condition and the motor is backfiring inside the crankcase. Most of the time it is due to a carburetor problem, idle needle adustment, linkage holding a throttle plate open slightly, a vacuum leak in the crankcase or intake manifold, etc. Thermostats that do not allow a motor to come up to operating temperature can do the same thing.

Take it back to the mechanic. That break in procedure you describe is overkill. Read the owners manual for the correct version.

Thanks A1, is it normal during the break-in for the plugs to be wet with oil?

A1 Outboard · 03-20-2007, 07:19 PM

Yes