Motor Started Revving And The Prop Stopped Turning
Joshua Wengerd, Dalton, Ohio: "I changed the lower unit oil last year in my 9.9hp Mercury. The second time out after changing the oil, I was going full throttle for about 2 minutes when the motor started revving and the prop stopped turning. When I'd try to throttle up again and then go past half-throttle, it would do the same thing. The first time out I ran the motor for 10 minutes. Someone suggested that there might not be enough oil in the lower unit. Both plugs are still in the lower unit."
A simple answer: you spun the hub in the prop. Remove the propeller and take it to a prop-repair shop. You'll be back in business quickly and inexpensively.
Can't Get Old Motor To Start
Jim Ferris, Holly, Michigan: "I have an old Johnson 4hp motor that has not been used for a few years and I can't get it to start. It's not seized and seems to have compression. I've replaced the spark plugs and used fresh gas. Can you give me some pointers on this problem? Also, do I have to use a lead substitute in the fuel? Thank you for any help you may have."
Here's where you have to make some hard decisions: If the engine has no spark (which I believe is probably the case), the engine (after 34 years) needs points, condensers, and coils. That'll run you close to $100. If it has spark (which I doubt), the carb needs to be removed and cleaned. The carb kit is about $20, I believe. That said, if you were to try to sell the engine as-is, you might be able to get $50 for it. Hard decisions? I warned ya!
Simple Or More Complex Fix?
Scott Kellin, New Brighton, Minnesota: "I own a 1984 Merc 50hp tiller I bought new. I've paid attention to the motor over the years, run good fuel, done the maintenance, kept it clean, etc. and have had no problems. Last year it started a little harder and didn't idle well. Seems to starve out at idle. Other times it feels like it's idling on 2 or 3 cylinders, but if I increase the RPM, it smoothes out. I've never touched the carbs. Is it time for a carb rebuild? If so, how big a job is it? Could it be a weakening electrical component? What else should I look for, short of a new motor? Thanks."
All your clues lead to simple carburetor rebuilds. The carbs are easy enough for a practiced person to do, but could lead to some serious problems for a novice. If you feel adventurous, you might want to get a SELOC service manual from West Marine or Boat US. Otherwise, taking it to a Merc dealer is probably the best answer.
Recommendation On A Stainless Prop
Jake Tuck, Great Falls, Montana: "I'm buying a 2005 ProV Lund with a 250hp Mercury Verado. I'm looking for a recommendation on a stainless prop -- diameter/pitch/number of blades and manufacturer. I'm interested in top-end speed with 2 fisherman and gear."
Okay, if you spend 40 grand on this rig, and it runs 17 mph based on my recommendation, are you going to come all the way to Virginia to wail away on me? My answer to you, and to the hundreds of folks who ask me the same question, is "What does the dealer suggest?" He knows the boat, he knows the engine. Merc makes excellent props. This is a new engine, and Merc has spent countless hours testing it under many conditions.
