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« on: October 18, 2017, 06:49:44 am »
My boat mechanic and I are stumped, so I thought I would ask on here because this forum has the greatest wealth of mechanical knowledge. I know it not bike related, but some of us fish aswell, I'm sure.
My boat capsized when my yard flooded during cyclone debbie. The motor was under water (fresh) for about 8 hours before I could retrieve it. The next day my mates and I removed plugs cranked her over sprayed her with CRC, dewatered and got her running. No problems. I started her up a few times over the next month or so and would have her running sweet. Took her out on the water and under load she would cut out. So I gave her to a mechanic, because I'm still dewatering bikes.
The mechanic has swapped over coils, cdi unit, pick up sensors, gearbox, fitted a pullstart to eliminate the starter circuit etc. Motor has good compression. It starts and will run on a hose for as long as you want. But in the water it will conk out after say 20 minutes. It will start straight away and run fine, then randomly conk out. Each time it starts straight away and runs fine. The cutting out happens at random intervals. The only thing he hasn't replaced is the wiring loom, that will be the next effort. Someone also suggested crank seals. And also selling the motor and buying a new one, but I can't pass on a lemon. If anyone can shed some light or point us to something obvious that has been overlooked that would be great.
Its a low hour Mercury 40HP lightning 3 cylinder.
Thanks in advance.