Over the past several months i've been dealing with a water in fuel problem. And now it has evolved into a rough idle and stalling problem. I will try to be as brief as possible. The problem started six months ago with water in my water/fuel filter. I had to pump out my internal fuel tank using the prime bulb. I got most of the water out and I treated the rest with seafoam gas treatment. I also replaced the fuel filter and spark plugs. Here is the problem. The engine is very hard to start. I have to put the prime start switch in emergency position to get it to start. Once started it idles rough and dies. I drained the bowls of all three carbs. and checked the fuel lines for abstruction. All looked good. I sprayed the carbs with carb cleaner to displace the water droplets I found on the flap valves. After all that the problem remains. I checked to make sure that the new spark plugs were firing and they were. I did notice that the bottom carb is the problem. The reasoning is that when I removed the spark plug wire from cylinders 1 & 2 (counting from the top down) the engine would stall instanly. Pulling the wire off #3 has no effect on engine. I"m almost positive the carb needs to be cleaned.
Question #1. How difficult is it clean (not rebuild) a carb with out a manual and is there a differance between cleaning and rebuilding.
#2. If I clean one should I do all three.
#3. Or should I shell out 300+ to have an authorized shop do the work.
not hard at all, I will suggest a manual but they are easy carbs.
the hardest part is dealing with the oil tank.
if the needles are not damaged most the time simply pull the fuel bowls, remove the rubber plug for the pilot fuel jet,remove the jet,remove the main jet. clear them with a strand of copper wire spray every thing out good with a carb cleaner and reassemble.
the seafoam treatment is like tacking a fart on the wall.
clean your tank, pull a rag dipped in seafoam through your fuel lines, install a good water seperator, replace the fuel pump. the cavities in the pump will hold trash then feed it to the newly cleaned carbs making you repeat this process.
Thanks Rodbolt for the info. I stopped by a dealer in my area (Jacksonville, Fla) today and they could not find a manual for my specific model engine. They were themselves using just a general outboard service manual. I also went to the Yamaha web site and they were out of stock. I have a 50TLRD Yamaha 2005 model engine. If there is anyone out there that knows where I can find one please let me know.
As far as the carburetor I will tackle that this saturday. It does not look that complicated. When you say run a rag dipped in seafoam thru my fuel lines, do you mean the fuel lines from the pump to the carburetors? Is it possible to clean the fuel pump also? I will pump out the fuel tank and give it a good cleaning. What do you suggest I clean it with?
I pulled all three carbs off this morning. All went well. I pulled out all the jets that I could and soaked everything in carb cleaner. I will reassemble in the morning. I took some pictures but I could not paste them into this message. I also started pumping out the fuel in the tank. I only got about two gallons out, before it started raining. I will continue later if the weather permits. Does anyone know where I can find a service manual for make and model or should I just get a general service manual.
I rebuilt the carbs and I also drilled out the plug for the air fuel mixture screw. I set the screw at 1 1/4 turns from the seated position. The first problem is that I can't get the motor to idle @ 800. It idles at @1200 rpm. I have tried to adjust the air fuel mixture to get it with in specs. I think It may be gasket issue. The gasket that goes between the carb and intake manifold may be damaged and allowing air to pass thru. Just a thought. BTW I did not replace the gaskets on any of the carbs. The second problem is after I did the rebuild I went on a test run on the river and it ran fine except for the idle issue for a while approx. 45 mins. The motor started to stall at throttle up. If I go from idle to WOT it would die. If I slowly advance the throttle to @1500 rpm it would spit and sputter thru @2000 rpm and from there it will advance to WOT. If i keep the rpm's above 2000rpm's she runs fine. Any ideas?
I finally got the motor to idle. I had to sync the carbs and make some minor ajustments to the air/fuel mixture screws. She is idling at specs.
I purchased an external gas tank to get pass the internal gas tank issue. I pumped out all the old/fuel in the tank that i could. I don't think there is any fuel in the tank, but i'm not sure. I pulled out the fuel sending unit to see if there was any fuel in the tank and there wasn't any. I'm concern about water in the tank, because there was a little in the fuel/water seperator. Do you any of you have any ideas on how to clean the tank. thanks
After all the work performed on the carburetors and some minor linkage adjustments I took my boat out on the river last week and she ran great with on problems using an external. This pass saturday I went fishing thinking that my boat would perform as she did the week before, but to my surprise she didn't. The motor started fine and idled great (800+/- 50 rpms). I put her in gear and at @1300 rpms the engine stalled/bogged down and shut off. After several attempts to advance the throttle past 1300 rpms I noticed that the motor was not trimed all the down so i did so. (why I did this I don't know. Just hopping I guess.) Low and behold the took off like a bat out of hell up to max rpms. Go figure. From there the problem got worse. The motor started to shut off at idle meaning that the rpms dropped until the motor died. Also the motor still stalled/ bogged down and quit. It would do this no matter what position the motor was trimmed to. After playing with the throttle the motor would eventually go past 1300 rpms and run great as long as you kept the rpms above 1500 rpms. The motor would rev up and down if not in gear which puts me at a complete loss. I'm starting to think it may be that my fuel pump is going bad? Or do I need to clean my carbs again. I'm at a loss. Has anyone had this problem before. If so what was the fix. Thanks for your help in advance.
I am not sure if you ever found a manual but I have that same motor but in the 70 HP and found a decent manual on Craigslist in the boat area for about 8 bucks. There are a couple of guys that do it and it comes on a CD that you can print out as needed. Hope this helps.
i am having the same problem with a 50 2 strokd had it to the dealer 4 times , dumped the old gas, i also have a 20 micron filter in line ,so far he told me to run the gas out of the motor each time , this worked well ,causing it to start 1st time,which was a real treat because for the past 2 years it was a bear to start, any way took it out to the bay and it ran for 2 hours strait while coming back in it bogged down and stalled out ,could not get in past idle speed i to am at my wits end its a 05 also time to dump it???