140 johnson vro 1989 runs good with ear muffs but not in water

I get her running yesterday on the earmuffs. Sounded great idled perfect and no backfiring. SO I tried the cylinder drop test and took off the wire from each cylinder while idling. When I pulled cylinder 1 and 2 the motor killed but cylinder 3 and 4 made no difference. Anyways took it on the water and left the boat on the trailer. Got her to idle barely and then I put it in gear to load test and she killed. It did seem to run at 1/4 throttle but anymore than that and killed everytime. Everyone is telling me to rebuild the carbs which I know I need to do because the gaskets are worn, but now I think it could be ignition. But why does the motor purr like a kitten on earnuffs but soon as it hits the water it barely will start??

Re: 140 johnson vro 1989 runs good with ear muffs but not in water

As for running only on muffs, There is more back pressure on the exhaust when you drop it in the water. On the muffs it's venting freely into the air but it has to push pressurized (from depth) water out of the way when it is submerged.

Re: 140 johnson vro 1989 runs good with ear muffs but not in water

Clean and rebuild the carbs. Besure and get the right kits. Verify OEM numbers if you purchace Siarra brand. It takes more time getting them off the engine than rebuilding them.

Re: 140 johnson vro 1989 runs good with ear muffs but not in water

The engine can sound perfect with no load and be running on two cylinders.

The best way to check is to use an inductive timing light so that you can "read" the spark over a range of RPM.

Pulling spark plug wires on a running looper can easily damage the powerpack, so you should test the powerpack following the instructions in your service manual.

General troubleshooting for the ignition system may be found here:
http://cdielectronics.com/downloads...linder 1988-2001 120-140 HP (Quick-Start).pdf