Last week I was running fine for about 30 minutes at 18 mph. I have a Mercury 5.0 with Alpha 1 Drive. All of a sudden it lost almost all power - down from 4000 rpm to 2000 rpm with the voltage meter jumping like crazy. I limped back, going no faster than 8 mph. There was nothing on my prop. Happened again, with Mechanic on board, after about 20 mintues. He suggested a change of coil. Did that. I tried it again after new coil installed, and after about 15 minutes, I was at FULL throttle and the boat was going no faster than 10 mph and kind of rough. Then I turned around and it felt like I was going to stall, going no faster than about 4 mph. Finally, called Seatow to get me down the canal safely and not wanting to stall. I always use Premium Hess gas with STP gas treatment. I had about 40 gallons in an 80 gallon tank over the winter which had StaBil in it. Then filled with premium Hess again and the StaBil Ethanol treament (similar but supposedly better than Startron). Please help with suggestions. Thanks. Rich
Running rough - need advice
- Thread starter Fun Time
- Start date
Battery cables are not loose. Thanks for the suggestion. Both batteries (starting/deep cycle)are brand new.The voltage meter does not jump all the time, just when it is happening (running rough). It seems ok the first 15 - 20 minutes of running time, then starts running real rough. Boat has 198 hours on it and is 9 years old. Thanks again to anyone with suggestions/advice.
yank on all primary wires including ign switch looking for a bad or loose connection. IMO you have an electrical problem. find where that voltmeter is connected then you will know the general electrical circuit area that is turning off and on.
And aside from the likely electrical problem , consider that your preference for pricey premium unnecessarily high octane fuel in a presumably normal-compression engine may be limiting your engine's normal performance somewhat.
Concerning my "preference" for using higher octane premium gas - - I found this nugget in another thread..."I'll add another vote for too low octane gas. Marine engines run under much heavier loads than a car engine, and will benefit from using a higher octane fuel. The marine fuel dock I use has gas STARTING at 91 octane, which they refer to a "regular", and 93+ octane as "super"." I just added that to show that I do not think it is bad gas. As far as electrical, I checked for loose wiring and it is all tight. Maybe it is the carb or fuel pump or...???
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I had something similar happen a couple of weeks ago dockside. It turned out to be that the rivet for the blade connector on the back of the kill switch had loosened over time.
The good news is that I was able to find the problem within 5 min. and bypass it by using the magneto terminals so that the switch worked backwards.
The voltage dropping to zero was the key for me, especially since the starter and radio still had power.
A new switch is an easy fix!
Good luck!
The good news is that I was able to find the problem within 5 min. and bypass it by using the magneto terminals so that the switch worked backwards.
The voltage dropping to zero was the key for me, especially since the starter and radio still had power.
A new switch is an easy fix!
Good luck!
I don't think it is ever possible to check all the wiring. And intermittant problems are extremely difficult to find. So my guess is you still have an electrical problem. It could be a bad connection almost anywhere on the boat. I would try manipulating (pull, shake, hit, etc) every wire you can touch while the engine is running. Don't forget the main power feed which is probably on the starter selonoid.
Mike
Mike
Please don't just tug on the battery connections or look at them. Dismantle and clean them. I had a similar problem a couple years ago. Started and ran pretty well till I operated the power trim. Engine stumbled and nearly quit. Try the trim while running and see what it does. Also remember your battery switch could be loose, corroded, or defective.