I have a late 1990s Yamaha 150 hp two-stroke that was fine until I took it to the dealer for a precautionary water pump change. When I got the engine back, it would do the visible discharge for a few minutes, then quit and the alarm would come on. I took it back, and it was returned with the same results. Now I notice there’s water in the lower cowl. What gives?

Dollars to doughnuts the pop-off hose has popped off - not what it’s supposed to do. It’s held in place by a tie strap that has a limited lifetime. Look under the electricals at the starboard rear of the engine,...

I have a 2007 cruiser that has two Volvo Penta sterndrives. Both are 5.7 liter OSXI engines. When I refuel, if the starboard tank takes 40 gallons, then the port tank will take 60 gallons. This consistently happens even though I’m careful to operate both engines at approximately the same rpm and when refueling always fill each one full. The dealer says that it is common to have unequal fuel usage on duplicate engines. That big a difference seems wrong to me. What do you think? What should be checked if you agree with me?

I concur that the 20-gallon disparity isn’t right. Newer engines have many sensors that pass their info to the ECM. The ECM collates that info and changes spark intensity, timing and fuel distribution in order to give...

I inherited a V-6 Johnson from my father-in-law. I can run this engine all day at 4500 rpm. Any faster, and within a minute the overheat alarm comes on. The water discharge is always strong; the water gushes out the two holes at the top of the engine. The scenario never changes. Any help?

You’ll need a friend for this one. One of you drives while the other uses one of those handy temperature guns to check the external cylinder temperatures. I’d bet that at 4500 rpm, all six cylinders are showing...

My 1998 Baha 454 Merc has a surge problem. It will surge 200 to 400 rpm from cruising speed, then drop below the speed I was at. I’ve had five topnotch marine mechanics work on my boat, but no fix.

If I were working on it, I’d sit by the engine with an inductive timing light until the engine dropped rpm, then attach the timing light to one plug wire after another. I’m guessing that a plug is dropping out of...

Why is my boat service so expensive at the dealership? Mark Willis, Cedar Grove, TX Excellent question - one most boaters don’t ask, but just complain about.

First, your boat is designed with your dream in mind: sunpad, swim platform, fishbox and stowage aplenty. Unfortunately, the swim platform covers the outdrive, which means the boat often has to be removed from the trailer...