Basic things to check on an outboard?

Discussion in 'Watercraft' started by Nick Clayton, Jun 11, 2013.

  1. Today I took a new to me 15' Smokercraft and 25 HP Merc 4 stroke that I am acquiring from a fellow forum member for our maiden voyage. A buddy from work went with me.

    We put in at Manchester, and putterer around a bit just to get a feel for her. The motor starts first pull and idled fine, however after a few minutes of running it started to stall. It acted like a car with a bad fuel filter....when I throttled it it would just sort of bog down, lag, and try to stall. If I backed off the throttle it would settle down.

    Anyway, ended up taking it to a shop as I know nothing of Outboards. Shop says most likely something in the carb from sitting for a while, and hopefully that's all it is, but it occurs to me that if I'm to be a boat owner now it would be a good idea if I learned a little bit. I'm sure this will happen again in the future and it would be nice to know some basic things to look for.

    So, what would you have checked in this situation? What are some basic things to check whenever an outboard acts up? What about any specific tools that would be happy to keep in the boat just in case?

    I am good with the mechanic checking this out for me, would just like to become more self sufficient in the future
  2. That was my boat, have not used it much the last year or so. Whatever it takes to get fixed, I'll cover it.
  3. 1st thing.... make sure the impeller works or running it will lead to a bigger problem.
    Alex MacDonald likes this.
  4. It pees real good.
  5. <insert thumbs up sign here>
  6. Jay, not sweating it at all. The guy I talked to today said it sounds like its a pretty simple fix. I'm mainly just interested in learning what to look for in the future.
  7. Nick congratulations on your new acquisition, may it provide you with many years of fish catching fun.

    I have to agree with the mechanic that it's most likely residual gas dried up in the system if it hasn't ran in a while. As for your 4 stroke, I had a similar situation with my 2 stroke trimmer. I purchased a simple carb rebuild kit containing new gaskets, springs, etc. and in no time had it running again as good as new.
    Any advise I could give to you, especially if you plan on running it in the salt, is to flush it with fresh water after using it, keep all of the internal parts coated with a corrosion inhibitor, and most importantly, that every electrical connection you have that goes to the motor, battery, ignition, etc. is thoroughly protected from a salt environment. You cannot be anal enough about this, especially when it comes to outboards. Nothing's worse than a ruined trip when the tide is taking you out to no mans land and you can't get the motor started simply due to a bad connection. It's also wise to use a good synthetic oil mix for the gas too as you won't have to worry about a gas stabilizer when you store it for a period of time. Oh and disconnect the gas line from the motor while it's running too and let it run all the fuel so you don't have a similar situation in the future. I have a 9.9 Merc that I occasionally use on the salt and so far have had no issues with it going this route. My two cent's worth.
    Oh, and feel free to PM me if you have any other questions on the motor that I can help you with.
    Nick Clayton likes this.
  8. Great tips, thanks Richard! Everyone I talked to said they thought it needed a carb cleaning and rebuild, no big deal. No figured I'd have a pro do it the first time and ill research so I know how to do it myself if it happens again
  9. The other big thing to me is to run non-ethanol gas. Ethanol really can screw up those motors especially older ones. Paid for a lot of tune ups till I learned that. Run it in all of my small engines,ATV and boat motors.
    Jim Wallace likes this.
  10. Nick,
    When you have those carbs rebuilt. Make sure that they sonic clean them! It will get the ultra fine powder that ethanol produces when it sits. There are a few ethanol free gas stations around. You can do a search on the net to find one near you. It is worth the effort to run it. Also installing a fuel water filter.
    Congrats on the new ride.
    You do know what "boat" stands for ?
  11. Thanks everyone.

    I keep reading about ethanol fuel and how bad it can be for these motors. Guess I'd better find a place that sells non-ethanol.

    It sure was fun while it lasted, and I coud tell that I'm very much going to enjoy fishing out of this thing! I plan to do as much research and learn as much as possible so that I am better equipped to handle any similar situations in the future.
  12. For the ethanol free gas, this site helps:

    Beyond that, it's normally recommended that you rebuild the water pump every year or two, depending on where you're running the boat AND remove and run a coathanger or something through the piss tube when it's been stored. That clears out any bugs that have decided to make their home in it.

    Of course, I'd take the frequency with a grain of salt. I've got an 89 Johnson 25 that I recently rebuilt the water pump on. Had a heck of a time getting the lower unit off over the shift rod. Turns out it had a nice wedge of the original paint on the rod that jammed in the impeller housing. Indicates to me that the lower unit had never been removed!

    Turned out the water pump looked only slightly worn (still rebuilt it) but the piss tube was blocked.

    Had a similar symptom to yours that pointed me to the water pump. After running well for a while I'd suddenly lose power (about half). Throttle down to idle and it was fine. Throttle back up right away and you'd only get half throttle again. Run it at idle for several minutes and it started running OK. Owners manual indicated this was a coolant flow problem.
  13. Running ethanol free all the time is a PITA. Service tech at 3Rivers told me to run one or the other. Switching back and forth can cause more problems than running ethanol fuel. Treat your fuel with the fuel stabilizer of your choice and then use your boat. Letting fuel sit is where the problems come from. Been running ethanol fuel as long as it's been out and have had to rebuild 1 carb, on my kicker, in all the years. Use your boat and ethanol issues won't appear.

    Hammer away.
    Nick Clayton likes this.
  14. The ethanol free is more recommended for older engines. My 89 2-stroke manual says:
    "Preferred Fuel: Any regular unleaded, regular leaded, or premium unleaded gasoline having the recommended octane rating and not extended with alchohol..."
    My main concern would be the following, also from the manual:
    "Alcohol attracts and holds moisture which may cause corrosion of metallic parts of the fuel system."

    Being a new boat owner and knowing how much a boat is already a "hole in the water..." I'd rather err on the side of caution. I consider it preventive maintenance.
  15. I think you nailed's not that there is anything wrong with burning ethanol gas, it's that it attracts water when it sits in your tank for a long time. I can see why that would be a problem for a boat, but it's not going to cause any issues on your commuter car.
  16. Nick, as others have said, IMHO, it might be a fuel issue.

    I would guess that Cheez/Jay let this boat sit for a long time with only a partially-filled tank and that he didn't pour fuel conditioner into the tank.

    The worst thing to do is to have a not full gas tank. That just allows a lot of condensation inside the tank and the ethanol gas exacerbates the water/fuel problem.

    Also, if it's sat for long, the ethanol can even deteriorate fuel lines and and other components and this crud can clog the lines.

    You might wanna read this:

    I'd get rid of the old fuel, clean the fuel system as best you can and then enjoy your new vessel!
  17. sounds like gas to me, too. The two best days in a boat owner's life is (1) when he buys it, and (2) when he sells it! One thing I do is pull the fuel line off as I motor up to the dock, and let the gas in the bowl go through the engine as it idles. Once the motor shuts off, I know there's nothing in the carb to gum up the works, and no ethanol sitting around to screw up the gaskets in the carb.
    Jim Wallace likes this.
  18. good advice, and if it will sit awhile make sure to fully drain the carbs. i know on my honda there is still gas in the carbs even after running them dry. on the hondas it is easy to fully drain each individual carb.

    i will concur also on fuel treatment... my boat runs better after 100 hours with treated fuel than when i got it used after sitting awhile and having the carbs sonic cleaned.
    Jim Wallace likes this.
  19. While we're on the topic- don't run that gas that's been sitting in a can in your garage for the last 8 months. Put that stuff in your truck or lawn mower and use fresh gas in the outboard. I recommend an in line fuel/water separator, $30 for piece of mind.

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