Re: High Speed Miss 68' 50hp merc.
First off, the rectifier will have nothing to do with the way this motor runs.<br /><br />2nd, the fact that the primer won't pump up could be an indication that the fuel pump diaphragm is ruptured and it's dumping raw gas directly into one or 2 cylinders. You can check this by pulling the fuel pump off and checking the diaphragm for pinholes. The back of the diaphragm shouldn't be wet with fuel, either.<br /><br />3rd, you need to take all (4) spark plugs out, stick them back in the plug boots, lay them against the block, and crank the motor over. You should see a 'hot' purplish spark from all plugs. Any less won't run the motor. If you want to make a "poor man's" test plug, buy (4) non-resistor car engine plugs with extended tips, doesn't matter what they came from. Break off, cut off, or grind off the ground electrode leaving only the center. If the spark will jump this plug, it's good.<br /><br />4th, are you sure of the year? Sounds like you're confused as to what spark plug this motor should carry. A true '68 would have Lighting Energizer electronic ign, with an external ign coil, and a switchbox mounted on the front inner cowl support.<br /><br />If you have a magneto, you'd have none of that, only the mag bolted to the motor with plug wires coming out.<br /><br />You should only use Permagap plugs with the electronic ign (L76V or equivalent), and conventional-electrode plugs with a magneto ign (probably J4C unless you have one of the 'oddball' years with a long-reach plug).<br /><br />If you post your Ser. # we can pin down the exact year.<br /><br />If cyls 3 & 4 have good spark, you'd want to rule out the fuel system as a problem. Check the fuel pump; also pull the main jet plug out of the front of the carb (lower center) and attempt to flush fuel thru the carb with the primer bulb. It should come 'gushing' out of the main jet area. Then you'll at least know fuel is getting into the bottom carb. You may need to pull the float cover off the carb and inspect/clean/blow out as needed. You should be able to do all this without pulling the carb off the motor. If it's gunked up real bad you'll need to remove the carb. Pick up a Sierra Marine #18-7006 gasket kit and it'll have the small gaskets you'll need to reassemble the carb. Cheap and readily available thru NAPA or
www.boatfix.com amongst others.<br /><br />Note that you could have 'trash' in the distributor cap which can cause a misfire so that's something else to check out if you suspect spark issues.<br /><br />Anyway, fill us in on the particulars of your motor, once we pin down the exact year we can probably help further.<br /><br />HTH.......ed
cant afford and need to get to those STRIPERS while their hitting top water. Thanks a million!!!<br />p.s.<br />I was shocked to find that this engine has no alternator(generator)and found that same year model had the option of one. Any idea what kind of issues to encounter by trying to add one?
