Editor's Note: This archived column first appeared in April 2005.

Acts Like It's Running On Just 1 Cylinder

Scott Haacke, Omaha, Nebraska: "I have a 1986 20hp Merc outboard that has been running inconsistently. It cuts out and acts like it's running on just 1 cylinder. Even when it does kick in on both cylinders, it still has no get up and go. The boat used to plane out and now it doesn't have enough power to do so. I've replaced the plugs, both coils, and have run an appropriate amount of fuel cleaner through the last tank, but it still doesn't run like it should. My questions are: Does this model have a fuel pump? Does the carburetor have a float or a vacuum diaphragm that may need replacing? Hope you can give some idea what I need. Thanks."

Before you approach this with the "shotgun" method, let's try to identify areas of suspicion. First, look at the bottom of your boat. If there's no growth on the hull, then you know that's not the problem. A 20hp engine is really marginal, so look to see if you've been adding stuff all along that would increase the boat's weight. If not, that's not the problem. Is the hull waterlogged? Flotation will suck up water and triple a boat's weight in a heartbeat. If that hasn't happened, then that's not a problem. Now you're back to the engine. Look at your throttle linkage. Is it opening completely? That means timing advance and carburetor. If it is, check your spark. It should jump a 3/8" gap. If both cylinders do, then that's not a problem. Check your carburetor to see if it's picked up water somewhere along the line. Replace your sparkplugs with the proper heat range (that's cheap!). If you're okay so far, do the dreaded compression test. The readings for both cylinders should be within 10 percent of each other. If none of this works, have you considered a FOR SALE sign?

Johnson 70hp 4-Stroke For Trolling?

Darlene Kozey, Churchbridge, Saskatchewan: "We're thinking of purchasing a Johnson 70hp 4-stroke for our 16.5-foot Crestliner. We do a lot of trolling. Do you recommend trolling with 4 stroke or 2 stroke?"

Actually, I do my trolling in a classy hot rod. Attracts more girls than fish. If you're bent on fishing, you'll be hard-pressed to do better than the 4-stroke 70hp Johnson, which is a Suzuki under a different cover. I've seen 6000+ hours of abuse from watermen before serious repairs need to be done. Just remember that all the 4-strokes emit more carbon monoxide than direct-injection engines, so don't troll from an enclosure that may backdraft the fumes.

Continued -- click on page link below.