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Hello all,
I'm new to this site but I've seen several great write-ups on here. I'm hoping you can help.
I repowered by boat with a 2013 Yamaha F150 with less than 100 hours on it. The engine came off of a commercial boat. Supposedly the guy I bought it from was selling it because he had two right hand rotating engines on his big catamaran and was having trouble docking it. The engine ran great on a stand with solid compression, smooth idle, etc...everything you would want from a nearly new motor.
I installed the new engine on my boat a few months ago along with new Yamaha control cables and the basic Yamaha tachometer. The boat started up fine and I was able to use it for roughly 20 hours until I ran into issues. I was fishing and was heading in at ~4200 RPM's and everything was smooth. All of a sudden the engine died. After examination I realized the fuel bulb was completely sucked dry. Obviously I had sucked in something from my fuel tank that had blocked between the fuel pickup and the fuel bulb. After getting a tow, I brought the boat home and disconnected all of the fuel line and the anti-siphon valve. I also inspected the interior of the tank (with a fuel-safe boroscope) and did not see anything floating and the plastic tank looked remarkably clean. I was unable to remove the fuel pickup tube without damaging the fuel tank so I didn't go any further there.
Next I decided that I should drain the entire fuel system and flush the tank. Luckily I was down to about 30 gallons of fuel so it was a manageable amount. I hooked up my handy dandy 12V fuel pump from the auto parts store and drained all of the contents into several plastic gas jugs. There were no blockage issues while draining the fuel tank and I filtered it through a 10 micron filter. To test the fuel, I first ran it in my KLR 650 and it ran fine. So as not to waste 25 gallons of fuel I ran the rest of that fuel through my truck with absolutely no issues. I also replaced the fuel hose from the boat tank to the filter, replaced the 10micron Racor in the boat, and replaced all fuel lines and fuel bulb to the engine. Once the tank was empty, I set up a circulation loop with new fuel through the tank and circulated 5 gallons for 3 hours with no issues. I drained that fuel out and added 10 gallons of fresh. After feeling pretty good about the boat fuel system I decided to clean out the entire fuel system on the motor.
I started with the main filter on the front of the engine. When I pulled it, it looked clean but I replaced it anyway. I followed the fuel lines back to the two fuel pumps and removed them. They visually looked okay with no perforations or tears in the pump membranes. Next, I removed the VST and completely drained and disassembled it. There was no residue inside it afte removal and the small micron filter was really clean. Next I moved to the fuel rail and flushed it. Finally, I removed all of the injectors and sent them off for cleaning and reinstalled them when I got them back. I also replaced the two F-shaped filters on the engine in case they were clogged. After this I reassembled everything and did a visual inspection for any places there might be a vacuum leak. Like I said before, the engine ran perfectly for 15 hours until I had a blockage of fuel.
After all of this I decided to hook up my boat to a 5 gallon can of brand new fuel and try running it. After priming the bulb, the engine would not start. I though maybe I had an issue with no fuel in the VST so I primed the bulb again and cranked the motor. I was trying to start the engine with throttle in the neutral/idle position, and it still would not start. Next, I moved the throttle forward and got the engine to fire. It would only stay running if I kept the RPM's at >1100. As soon as I let off the throttle it would die. I also noticed that a plastic component on the top of the throttle body was very hot to the touch (I think it is the idle speed control valve).
I am currently a bit mystified at this problem, so I decided that it was time for a trip to the local dealer. I brought it there and told them what had happened to me. I also let them know that I had cleaned my boat's fuel system, but that I wanted them to do a diagnostic with an external tank. I did not mention that I cleaned the entire fuel system as I wasn't sure if this would hurt my warranty. I also mentioned the hot electrical component on top of the throttle body. I dropped the boat off 3 weeks ago and they have not been able to fix the problem. When I spoke with the mechanic, he said the fuel system was very clean so that was not the issue. Next he indicated there was an issue with the throttle position sensor and that he had changed it out. He also indicated he thought the previous owner had messed around with a little idle screw (screw with a torque bit head that I think adjusts the position of the throttle valve). I did not know what screw he was referring to so I told him that so he didn't think I was making adjustments Finally, he indicated the idle speed control valve was stuck @100% open, and he was working on adjusting it and thought he had a fix for it. He also mentioned the spark plugs were pretty black..
My questions are the following? If the engine ran perfectly for 15 hours then died because of a fuel blockage, how could that affect the idle speed control valve and throttle position sensor? Before the fuel blockage occurred, the boat started and idled at ~700 rpm with no problems. Is it possible that whatever I sucked into the fuel system may have caused the idle speed control valve to get stuck open? Is there any other sensor that could be causing the idle speed control to stay stuck at 100%? If the idle speed control valve is stuck at 100% open, shouldn't that mean air is able to get into the throttle and the engine should start up? I don't know if he has done anything with the mass air flow sensor, so I will wait to ask questions on this.
Any help from this forum is very much appreciated.
I'm new to this site but I've seen several great write-ups on here. I'm hoping you can help.
I repowered by boat with a 2013 Yamaha F150 with less than 100 hours on it. The engine came off of a commercial boat. Supposedly the guy I bought it from was selling it because he had two right hand rotating engines on his big catamaran and was having trouble docking it. The engine ran great on a stand with solid compression, smooth idle, etc...everything you would want from a nearly new motor.
I installed the new engine on my boat a few months ago along with new Yamaha control cables and the basic Yamaha tachometer. The boat started up fine and I was able to use it for roughly 20 hours until I ran into issues. I was fishing and was heading in at ~4200 RPM's and everything was smooth. All of a sudden the engine died. After examination I realized the fuel bulb was completely sucked dry. Obviously I had sucked in something from my fuel tank that had blocked between the fuel pickup and the fuel bulb. After getting a tow, I brought the boat home and disconnected all of the fuel line and the anti-siphon valve. I also inspected the interior of the tank (with a fuel-safe boroscope) and did not see anything floating and the plastic tank looked remarkably clean. I was unable to remove the fuel pickup tube without damaging the fuel tank so I didn't go any further there.
Next I decided that I should drain the entire fuel system and flush the tank. Luckily I was down to about 30 gallons of fuel so it was a manageable amount. I hooked up my handy dandy 12V fuel pump from the auto parts store and drained all of the contents into several plastic gas jugs. There were no blockage issues while draining the fuel tank and I filtered it through a 10 micron filter. To test the fuel, I first ran it in my KLR 650 and it ran fine. So as not to waste 25 gallons of fuel I ran the rest of that fuel through my truck with absolutely no issues. I also replaced the fuel hose from the boat tank to the filter, replaced the 10micron Racor in the boat, and replaced all fuel lines and fuel bulb to the engine. Once the tank was empty, I set up a circulation loop with new fuel through the tank and circulated 5 gallons for 3 hours with no issues. I drained that fuel out and added 10 gallons of fresh. After feeling pretty good about the boat fuel system I decided to clean out the entire fuel system on the motor.
I started with the main filter on the front of the engine. When I pulled it, it looked clean but I replaced it anyway. I followed the fuel lines back to the two fuel pumps and removed them. They visually looked okay with no perforations or tears in the pump membranes. Next, I removed the VST and completely drained and disassembled it. There was no residue inside it afte removal and the small micron filter was really clean. Next I moved to the fuel rail and flushed it. Finally, I removed all of the injectors and sent them off for cleaning and reinstalled them when I got them back. I also replaced the two F-shaped filters on the engine in case they were clogged. After this I reassembled everything and did a visual inspection for any places there might be a vacuum leak. Like I said before, the engine ran perfectly for 15 hours until I had a blockage of fuel.
After all of this I decided to hook up my boat to a 5 gallon can of brand new fuel and try running it. After priming the bulb, the engine would not start. I though maybe I had an issue with no fuel in the VST so I primed the bulb again and cranked the motor. I was trying to start the engine with throttle in the neutral/idle position, and it still would not start. Next, I moved the throttle forward and got the engine to fire. It would only stay running if I kept the RPM's at >1100. As soon as I let off the throttle it would die. I also noticed that a plastic component on the top of the throttle body was very hot to the touch (I think it is the idle speed control valve).
I am currently a bit mystified at this problem, so I decided that it was time for a trip to the local dealer. I brought it there and told them what had happened to me. I also let them know that I had cleaned my boat's fuel system, but that I wanted them to do a diagnostic with an external tank. I did not mention that I cleaned the entire fuel system as I wasn't sure if this would hurt my warranty. I also mentioned the hot electrical component on top of the throttle body. I dropped the boat off 3 weeks ago and they have not been able to fix the problem. When I spoke with the mechanic, he said the fuel system was very clean so that was not the issue. Next he indicated there was an issue with the throttle position sensor and that he had changed it out. He also indicated he thought the previous owner had messed around with a little idle screw (screw with a torque bit head that I think adjusts the position of the throttle valve). I did not know what screw he was referring to so I told him that so he didn't think I was making adjustments Finally, he indicated the idle speed control valve was stuck @100% open, and he was working on adjusting it and thought he had a fix for it. He also mentioned the spark plugs were pretty black..
My questions are the following? If the engine ran perfectly for 15 hours then died because of a fuel blockage, how could that affect the idle speed control valve and throttle position sensor? Before the fuel blockage occurred, the boat started and idled at ~700 rpm with no problems. Is it possible that whatever I sucked into the fuel system may have caused the idle speed control valve to get stuck open? Is there any other sensor that could be causing the idle speed control to stay stuck at 100%? If the idle speed control valve is stuck at 100% open, shouldn't that mean air is able to get into the throttle and the engine should start up? I don't know if he has done anything with the mass air flow sensor, so I will wait to ask questions on this.
Any help from this forum is very much appreciated.
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