5.8 omc cuts out intermittently under load

[pontiactarestorer]

I have a 92 OMC 5.8 cobra that cuts out under a load, 2000 rpm on up. The fuel system had water in it. I drained the tank, rebuilt the carb, changed the fuel filter twice. I suspected leftover moisture, but by now it is cleared out. The coil was bad, so i replaced that. I replaced the ignition and kill switch. Good connections at starter relay. good connection at the main harness plug. It fires up and runs great. Just when i give it 3/4 to full throttle it suddenly and quickly cuts out only for split seconds. And to make it more crazy it seems to only do this when first using the boat. if i keep on running it eventually it stops doing this. My next test will be running a jumper wire to the ignition for a dedicated power supply. after that i can only assume it is either the Distributor pick up coil, or the shift interupter module. I would hate to guess at either of those for they are Expensive. Any help will be appreciated!

 

[sixgiesens]

Re: 5.8 omc cuts out intermittently under load

Having same problem to date 5.8l 1989 Cobra, Phaser 230:
1. Replaced throttle and both sfhift cables -bad
2. Replaced spark Plugs - bad
3. Checked Points - good
4. Checked Rotor and dist cap - good
5. Checked Carb accell pump for spray flow - good flow (note can buy pump only from A-zone) Problem still there intermitent
6. Drained & Cleaned gas tank, replaced fuel filter - Problem there but happens less often. (May need to drain Carb Bowls)
Next Steps:
7. Mechanic said since intermitant should replace Shift Sssist Module about $80 parts. Said easy to do, why pay him do it your self. go cheaper to more expensive to resolve.
8. If still there after 7 Mechanic said consider both replacing control box (Loose but not horrible) and re adjust shift cables on the water.(about $280 labor). Mechanic said do not do this one yourself.
9. Consider switches on shift plate above motor

10. Now it gets expensive internal engine or internal out drive


Good Luck