50hp Merc losing power

[Nismospeed]

Hi all,
My wife bought me a pontoon last month, went up north to work on the bathroom at my house, came back to the east and FINALLY got out on the water today. My outboard had some issues firing up this evening, but I quickly learned that it was an idle adjustment. Ran it for 10min at a little above idle, slowly lowered it to neutral and she died. So, I made an adjustment to the set screw and was fine. BUT...my problem lies at WOT. I have no tach, so bear with me on this. GPS says we hit 18mph out there at WOT. We kept steady at that speed for quite a bit, then went neutral for a few to watch the sunset. Not great, but not terrible for a 50hp on a 24' barge. On our way to recover, we went the same speed, but half way back, lost power and dropped to 11mph at WOT. I could hear the RPMs bogging down, so I backed off to neutral for a few minutes, and then opened it up again. Same result. Im assuming that after adjusting the idle, I probably shouldve adjusted something else too to counter this? Maybe totally unrelated. Fuel/oil mix is fresh and fairly accurate, so I doubt thats my issue. Any advice would be greatly appreciated. Boat/engine details below...

 

[Cheaptoon]

Re: 50hp Merc losing power

The top speed sounds pretty quick for a 24 foot ,I have a 20 footer with the same engine, it does 19.4 at wot, Sounds like you have a carb issue, Does it come right out of the hole? Or does it hesitate a bit? How was the water conditions when it cut down to 11 mph? Because with that speed it sounds like you are propped right, but it is hard to tell without a tch. How long did the boat sit without running before you got it? it is highly possible you got some trash Come through the carb. Try using a can of seafoam, I have had real good luck with this stuff, Could save you a a few dollars on a carb Job, Good luck

 

[EGlideRider]

Re: 50hp Merc losing power

Rebuild the carbs. If they aren't the problem now, they will be soon. Great insurance if nothing else.

 

[lakegeorge]

Re: 50hp Merc losing power

The speed that you are getting is great for a 24 footer. Did you check the bulb on your fuel hose? The check valve may be sticking also. I would look at the plugs and other simple things before I start rebuilding anything.

 

[Cheaptoon]

Re: 50hp Merc losing power

The speed that you are getting is great for a 24 footer. Did you check the bulb on your fuel hose? The check valve may be sticking also. I would look at the plugs and other simple things before I start rebuilding anything.

This is good info, Fuel lines tend to rot from the inside, especially with the gas having ethanol in it, this crap rots rubber, Some of the new fuel lines are alcohol resistant But not all of them. Also on these older motors, I would run some ethanol treatment every tank, I forget the name of the stuff but you can buy it at any parts store, The ratio I think is like an ounce to 8 gallons.

 

[Nismospeed]

Re: 50hp Merc losing power

The top speed sounds pretty quick for a 24 foot ,I have a 20 footer with the same engine, it does 19.4 at wot, Sounds like you have a carb issue, Does it come right out of the hole? Or does it hesitate a bit? How was the water conditions when it cut down to 11 mph? Because with that speed it sounds like you are propped right, but it is hard to tell without a tch. How long did the boat sit without running before you got it? it is highly possible you got some trash Come through the carb. Try using a can of seafoam, I have had real good luck with this stuff, Could save you a a few dollars on a carb Job, Good luck

Lots of questions to answer... Ok, first off, pops right of the hole. At its current condition, she is slightly hesitant. But before the drop in speed, she jumped out like a greyhound. The water conditions were awesome. Freshwater cove that was extremely calm, only one other boat was out, but guessing a 1/2mi away from us. Boat sat since October, when the rebuild began. Had new cushions, carpet, and some engine work done, and this is the first time it was on the water this year. Question for you... can I get the seafoam at basspro? Im going over there for the fuel line/bulb. And do I just spray it through the carb's butterfly? never used it before.

The speed that you are getting is great for a 24 footer. Did you check the bulb on your fuel hose? The check valve may be sticking also. I would look at the plugs and other simple things before I start rebuilding anything.

Thanks for the simple starting point. Im going to get that line and the seafoam mentioned above and give it a shot. if they dont solve the issue, i will replace the plugs. if that doesnt work, i will bite the bullet and have the carb rebuilt.

Thanks all for the input. How hard is it to install a tach? My console has the holes precut for virtually anything, but I have no idea how to wire it up. Id like to put one in so that I can give more useful details in the future.

 

[EGlideRider]

Re: 50hp Merc losing power

You can buy Seafoam at Auto Zone and it'll be cheaper than Bass Pro Shop.

Installing a tach is easy if the wires are already in the console, and they should be. If not, you'll need to run one wire from the tach to the engine.

The tach has four wires: hot, ground, light, and signal.

 

[Nismospeed]

Re: 50hp Merc losing power

ok, the hot/ground/light i can do, but where do i connect the signal at? again, ive never done one of these before, so call me a noobie and print me a book called "Tachs for Dummies"

 

[Cheaptoon]

Re: 50hp Merc losing power

ok, the hot/ground/light i can do, but where do i connect the signal at? again, ive never done one of these before, so call me a noobie and print me a book called "Tachs for Dummies"

The easiest way to do this is get the factory plug that plugs into the control box, I think it is a 5 pin plug, In that harness you will have a grey wire, this one goes to your sender on tach, A purple this one goes to 12v +, and a black one that will go to the ground on your tach. It is easier this way, However if you cant find a harness you can run a wire all the way back to your rectifier and pick up the tach signal there. If you have to go that route , there is a red and 2 yellows on the rec., It should go to the bottom most yellow on the rectifier. There should already be a grey wire attached to this pole.

 

[Cheaptoon]

Re: 50hp Merc losing power

Lots of questions to answer... Ok, first off, pops right of the hole. At its current condition, she is slightly hesitant. But before the drop in speed, she jumped out like a greyhound. The water conditions were awesome. Freshwater cove that was extremely calm, only one other boat was out, but guessing a 1/2mi away from us. Boat sat since October, when the rebuild began. Had new cushions, carpet, and some engine work done, and this is the first time it was on the water this year. Question for you... can I get the seafoam at basspro? Im going over there for the fuel line/bulb. And do I just spray it through the carb's butterfly? never used it before.




It sounds like you broke some of the trash loose, This seafoam should fix the problem, Do not put it in the carb throats, put it in the the gas tank and go out and run it, if it is gonna fix it , it will do it in the first few minutes of running., You might even put it in the tank and hook the muffs up and run it in the yard for a few minutes. Sea foam is real good stuff if the carbs arent too gummed up. Good luck

 

[Nismospeed]

Re: 50hp Merc losing power

awesome!! Thanks for the info. Im going out now (I have nothing else to do) and will report back this evening. hopefully tonight i can go snag a tach and get it wired up...but i doubt it. gotta get ready for my other 2 kids to come home tomorrow from their visit with their mother...sigh...enough said.

 

[Nismospeed]

Re: 50hp Merc losing power

Ok, so Im a few days late getting results back... but here we go. SeaFoam solution...success. Bought a pint of it....it said for 8-25gal, so I used almost all of it (probably 2oz left) for my 6gal tank (boooo to the plastic can). Also, I came across an electrical issue that baffled me, but caused me to open my helm and go through the wiring. In doing so, I found the connector for the tach. Its actually a 4-pin, but I identified the wires, and the color code that was mentioned above seems to match. So, now I can go get a tach and slap it together. Awesome. The wiring issue itself was weird. The main hot/ground to the battery are white and black. The black wire was fused, with dead fuse in place, so I swapped it out and hooked it up. Typically, the fused wire is hot so I hooked it back up and started testing my switch panel. Radio good, lights good, etc... Then the fuse popped so I sat for a minute or 2 and decided to go unhook it. In doing so, I noticed that the fuse holder had melted. Long story short, it turns out the previous owner had fused the ground. So, I fused the hot and everything seems normal. Anyone else encounter something like this? Ive done a lot of 12v electrical on autos, but this one was just weird to me.

One other question... has anyone ever used Yamaha RingFree? My father swears by it, and so does the man that recommended it to him. Just thought I would see what other users thought so I didnt make a biased decision on it. Thanks!!

 

[Cheaptoon]

Re: 50hp Merc losing power

Glad to see that the sea foam worked well, It usually does, it is kinda a miracle cure if you will, I would also recomend running that in the first tank after you unpack it next spring. As far as the ring free goes, I think it and the seafoam are pretty close to the same thing.The seafoam is a cleaner and decarbonizer and the ring free does the same thing. However the seafoam is a whole lot cheaper.