John Walls, Devils Lake, North Dakota: "I have a 1988 Yarcraft 1670BT with an 1988 Mariner 60ELPTO. Both have high hours. The engine is hard to start and it idles rough and dies a lot. It will do 26-27 mph top-end, but sounds like it is occasionally spitting and sputtering. When slow trolling, a high-pitched alarm goes off and will not stop until I shut it down for a while or run at full speed for a short distance. Should I have it rebuilt, or replace it with a new 4-stroke?"
A lot depends on "high hours." High hours on a 75 Suzuki is 3500. High hours on a 70 Evinrude of the same vintage is 750. And what happened during those high hours? I'd start with a compression test to see if all the cylinders are within 10 percent of each other. Then I'd do a carb rebuild. And then, by your alarm complaint, a water pump replacement. That's about $5000 less than replacing the engine.
Will Not Start Again Until It's Stone Cold
Jim Farrell, Boonsboro, Maryland: "I have a 4hp Mercury outboard and when it starts cold, it runs for about 20-30 minutes and then quits. It will not start again until it's stone cold -- probably not the same day. When I check it over it seems to have no spark. Would this be the coil or the ignition control box?"
The coil is the cheapest place to start, unless you have the service manual and test equipment.
Fuel Foibles
Mark Hixenbaugh, Romney, West Virginia: "I have a 2000 Evinrude 9.9 4-stroke kicker on a Lund 1800 Fisherman. The fuel bulb pumps up fine and the engine starts easily, but after I troll for a few hundred feet the motor starts to shut off. If I pump the bulb a few times it runs fine for a few hundred more feet. It also does this if I turn the throttle on more. The engine has a console throttle, not a tiller. I always use STA-BIL in the fuel. Help me, Doc!"
Either the fuel line is drawing air at the tank or the engine fitting, or the fuel pump needs repair. It would be rare for a fuel pump this new to need help, but that'd be the place to look if your fuel line has integrity.
Torque Specs For Tightening The Propeller
Ricky Plomin, Chicago, Illinois: "I have a 1992 30hp Evinrude outboard. Do you know what the torque specs are for tightening the propeller?"
Snug the nut down until you can't move the prop in and out on the shaft (you may get movement in and out of the shaft in the gearcase), then put the cotter pin through.
Grid Michal is an independent mobile engine tech with 40 years experience with OMC and 21 with Suzuki. He also subcontracts for several dealers and, to keep his brain wired, helps out at a marine electronics facility.
