Re: 91 Merc 75hp cutting out
Might be time for those carbs. As mentioned, check a couple of things first:<br /><br />Change your plugs and test for spark. Clean out coil post connections and coat with dialectric grease. Check coils as per manual specs.<br />Vent: If an onboard tank, blow in it. Air should pressurize/release freely.<br />Lines/primer bulb: Pressurize if needed to check for leaks; perhaps try bypassing the quick-connectors and run the fuel line straight to the pump. If you don't have a spare tank, get one. Use your new bulb and run the motor on the spare tank, thus bypassing the existing lines/pick-up tube in the gas tank. <br />Fuel Pump: Remove spark plugs. Ground each spark plug wire to the block (to protect coils). Run a fuel line from the output tube of the fuel pump to another tank or large glass bowl. Place motor on muffs. Turn motor over half a dozen cranks; fuel should pulse freely out of the line. Doesn't hurt to order the diphram kit and rebuild the fuel pump--it's easy. Make sure mounting gasket between the pump and the hole in crankcase is properly seated.<br />Carbs: Check that oil, &c. is not clogging the vent jet of each carb. <br /><br />Hopefully, you will find a kink in the system somewhere. Otherwise, remove front lower cowl, remove air box cover and plate, remove carbs, disassemble, soak in carb cleaner, reassy w/fresh gaskets and new needles and adjust floats as needed, and reassemble...not difficult, but not necessarily fun, either...<br /><br />Good luck!
