Re: 305/5.0L wont run
Hi I have a 1988 Four Winns with a GM 305/5.0L the engine cranks over an sputters but will not start. I have replaced the coil, distributor cap, rotor, checked for spark at plug and coil, ran a wire straight from the pos side of battery to the coil and nothing has helped. Any suggestions?
First... Are you getting spark? You're saying that it sputters. If it sputters, it sounds like it's firing. Crank your engine over and see if you're getting a good steady spark. Maybe your timing is off. You'll have to have a timing light (I just bought one a Oreileys for $40) and the Mercruiser manual to check this.
Second... How'd you check the gas for water? I JUST took a boat to the lake. It ran fine at home, but when I backed it into the water it would run terribly and eventually die. Depending on which way the boat was tilted, the fuel pickup would suck in either GAS (at home) or WATER when it was backed into the lake. I siphoned all the gas out and found a GALLON of water in my 15 gallon tank. I've tested for bad gas this way... just undo your fuel line to your gas tank, stick it in a gas can of gas that you KNOW is good, and try starting it that way. Spray some starting fluid into the carb to help it suck all that water/gas out of there. (BTW, if it starts good spraying starting fluid in the carb - then you definitely have bad gas).
Third... If it's getting gas and spark... maybe you're getting a poor spark. Make sure all your wires are tightly down on the cap, coil & plugs. Make sure they're on the CORRECT plugs (I've had an engine run poorly because two plug wires were backwards. If still bad spark, consider changing plugs & wires.
Fourth... Maybe your getting bad compression. Borrow a compression tester from Oreileys (they have parts that they give out on loan), and test each cylinder for good compression.
