Very technical and informative. I'm going through this right now and about to head of to certified dealer to get rectified. This video gives me piece of mind knowing that this is most likely my issue and that this type of testing will get things solved correctly. Thanks for sharing!
Harness and sensor issues can be difficult to isolate, but with the proper techniques and information, possibilities can be narrowed down quickly. We're always interested to hear about repairs for unique electrical and mechanical issues, so please check back with us when your motor is repaired and let us know how it went. Thanks, Tyler
Ended up being Ignition Harness from behind the key to the back of the motor. Took the pros at The Boat Center in Chippewa Falls, WI 20 minutes to trouble shoot!
The full diagnostic sequence for harness and sensors is fairly easy, but we wanted to keep the video to a few minutes. Part 2 will show the fix. Diagnostic sequence is detailed in Yamaha shop manuals and is more or less the same for all Yamaha 4 stroke. Any decent multimeter and you're in business. No substitute for having a shop manual for these types of issues whether you work on Yamaha 4 stroke or repair your own motor.
Having trouble finding "Part 2". Where is it? I'm having tilt/trim issues, but they seem to be electrical in that it's going slow and battery is full. I'm thinking I've got the short in the water pressure sensor, but will try to at least clean things out.
Thanks for the video. After swapping out the fuel pumps for no reason, your video fixed my problem. One question, engine now runs great, but I’m not getting a speed reading on my speedometer now. Could my ecu be damaged now or do I need to swap out the speedo sensor too?
The first thing I would do is check the Pitot Tube/water pick-up for an obstruction, which is very common. The Pitot is located in the forward edge of the lower casing on the gear case. The tube is almost invisible because it is tiny, about 1/16" interior diameter. If this tube is obstructed, you will get no speed reading at all. If obstructed, use a pick to clear the debris. If it is clear/ no obstruction, blow some compressed air into the Pitot to see if anything registers at the gauge. If its a digital multifunction gauge you'll need to be Key-On to check a speed reading. Analog gauges can be pressure checked while powered down. If you get nothing at the gauge while blowing air into the Pitot, motor has been running normal and you have normal reference voltage, 5.0V plus/minus .02V, at sensor connects/engine harness, speedo sensor ohms out normal, I'd drop the gear case and inspect the speedo connect (tiny hose barb or white plastic fitting with o-ring) at the top of the gear case. These connectors are very brittle on some models/HP, and if this connect is broken or the pick-up hose is not connected, you will get nothing at the speedo sensor (if so equipped) or at the gauge if the pitot hose connects to the barb on back of the gauge on older gauges, on systems with no speedo sensor. ECU damage would be the outlier, generally speaking, if there is significant ECU damage, there will be multiple issues with motor performance.
I have a 2004 f115 that runs good when you fire it up cold then you drive it a bit and it stalls coming back to neutral and won't start again without high idle then can't get it into gear
All Yamaha shop manuals can be bought through any authorized Yamaha dealer. They are quite pricy, but generally worth it whether you are an owner working on your own motor or a professional working on someone else's
I have a 2014 Yamaha 250 4 stroke with 650 hours. Has always run great. Recently, while cruising around 3400-3600 rpm's, engine shuts off. Starts right back up and runs fine for 30-45 minutes. Had yamaha mechanic trouble shoot and found nothing. Suggested ignition switch which I replaced. Still have same problem. Happened about 10 times now. Any ideas?
HI Sachel, Sorry for the late reply. This problem is difficult to diagnose without having the boat in my shop. Sounds like an issue with either a key switch failure or the main harnesses/DEC harnesses having a connectivity problem.
This was from a motor that was having a running issue from a shorted sensor that was creating reference voltage to drop below 5 volts and screwing with the engine harness.
Hi sorry for late reply. This motor came in with complaint regarding the DEC shift control. Motor was having issues coming out of forward gear (ultimately the failure was confined within the DEC system and harnesses and not main engine harness/sensors). We were checking voltages on the computer and noticed erratic reference voltage reads from several of the engine harness sensors. Yamaha usually specifies 5.00V reference for most of their engine harness/sensors, and we were seeing 4.95 to 4.98, so decided to take a look. The DEC problem was not caused by issues in the main engine harness, but I still wanted to publish this video just to show how sensitive these systems can be. Also, with older 4 strokes that still used three wire TPS like early 2000's F115, F150 and all 3.3 V6, engine harness/pressure sensor issues can cause major running problems if a water pressure/speedo sensor starts to misbehave from corrosion or connectivity issues. It throw reference voltage all over the range and then TPS voltage goes way out of spec which infuriates the ECU. Hell hath no fury like a dazed and confused ECU! One of the first things I check now with older F150 and 115 etc that has running issue and has also passed basic mechanical inspection (compression, manual shift check, gear oil and motor oil do not look like a milk shake etc) is to disconnect any sensor that has access to raw water such as speedo and water pressure while running the motor in the tank. If it miraculously starts to behave, it is likely dealing with engine harness voltage and corrosion issues. May still need a sync and link, but this step gets you close quick!
@@outboardst.comoutboardspec8631 First, Thank you for this detailed response. I'd love to see you go through these Diag procedures as you are an excellent instructor. With any modern engine auto/marine dealing with an "Infuriated ECU" (lol) will become more common as these engines and systems come under the control of the ECU and it's ever expanding family of control modules. The day is coming when the simple (better) engines retire and you'll be wearing a lab coat and pocket protector to fix them. I'm looking forward to seeing your channel and business grow. The tools you design and create will become industry standard must haves. Thank you and keep the content coming!
Very technical and informative. I'm going through this right now and about to head of to certified dealer to get rectified. This video gives me piece of mind knowing that this is most likely my issue and that this type of testing will get things solved correctly. Thanks for sharing!
Harness and sensor issues can be difficult to isolate, but with the proper techniques and information, possibilities can be narrowed down quickly. We're always interested to hear about repairs for unique electrical and mechanical issues, so please check back with us when your motor is repaired and let us know how it went. Thanks, Tyler
Will do! In on Friday!
Ended up being Ignition Harness from behind the key to the back of the motor. Took the pros at The Boat Center in Chippewa Falls, WI 20 minutes to trouble shoot!
Best case scenario
The full diagnostic sequence for harness and sensors is fairly easy, but we wanted to keep the video to a few minutes. Part 2 will show the fix. Diagnostic sequence is detailed in Yamaha shop manuals and is more or less the same for all Yamaha 4 stroke. Any decent multimeter and you're in business. No substitute for having a shop manual for these types of issues whether you work on Yamaha 4 stroke or repair your own motor.
Having trouble finding "Part 2". Where is it? I'm having tilt/trim issues, but they seem to be electrical in that it's going slow and battery is full. I'm thinking I've got the short in the water pressure sensor, but will try to at least clean things out.
Do you have a video to show how to check the tach on a 2008 Yamaha 4stroke
Thanks for the video. After swapping out the fuel pumps for no reason, your video fixed my problem.
One question, engine now runs great, but I’m not getting a speed reading on my speedometer now. Could my ecu be damaged now or do I need to swap out the speedo sensor too?
The first thing I would do is check the Pitot Tube/water pick-up for an obstruction, which is very common. The Pitot is located in the forward edge of the lower casing on the gear case. The tube is almost invisible because it is tiny, about 1/16" interior diameter. If this tube is obstructed, you will get no speed reading at all. If obstructed, use a pick to clear the debris. If it is clear/ no obstruction, blow some compressed air into the Pitot to see if anything registers at the gauge. If its a digital multifunction gauge you'll need to be Key-On to check a speed reading. Analog gauges can be pressure checked while powered down. If you get nothing at the gauge while blowing air into the Pitot, motor has been running normal and you have normal reference voltage, 5.0V plus/minus .02V, at sensor connects/engine harness, speedo sensor ohms out normal, I'd drop the gear case and inspect the speedo connect (tiny hose barb or white plastic fitting with o-ring) at the top of the gear case. These connectors are very brittle on some models/HP, and if this connect is broken or the pick-up hose is not connected, you will get nothing at the speedo sensor (if so equipped) or at the gauge if the pitot hose connects to the barb on back of the gauge on older gauges, on systems with no speedo sensor. ECU damage would be the outlier, generally speaking, if there is significant ECU damage, there will be multiple issues with motor performance.
Hey mun3726. Any chance I could ask you what your engines symptoms were for you to change both fuel pumps. I'm currently in a similar situation
I have a 2004 f115 that runs good when you fire it up cold then you drive it a bit and it stalls coming back to neutral and won't start again without high idle then can't get it into gear
How would one acquire a Yamaha shop Manuel. Or do you have to be a licensed Yamaha mechanic to get one?
All Yamaha shop manuals can be bought through any authorized Yamaha dealer. They are quite pricy, but generally worth it whether you are an owner working on your own motor or a professional working on someone else's
@@outboardst.comoutboardspec8631 jam
So what were the ohms?
I have a 2014 Yamaha 250 4 stroke with 650 hours. Has always run great. Recently, while cruising around 3400-3600 rpm's, engine shuts off. Starts right back up and runs fine for 30-45 minutes. Had yamaha mechanic trouble shoot and found nothing. Suggested ignition switch which I replaced. Still have same problem. Happened about 10 times now. Any ideas?
Hi Bob, sorry for the late reply. I'm curious to hear if you are still having this problem and what your mechanic has been able to find out.
this always happens if the WP sensor is incorrectly installed
Hey I have 2 350 Yamaha while driving the engines shut off getting electricity to the engine but console(tach)not coming on can you help me?
HI Sachel, Sorry for the late reply. This problem is difficult to diagnose without having the boat in my shop. Sounds like an issue with either a key switch failure or the main harnesses/DEC harnesses having a connectivity problem.
what was the problem the customer was having for you to look into the sensors? low voltage?
This was from a motor that was having a running issue from a shorted sensor that was creating reference voltage to drop below 5 volts and screwing with the engine harness.
What was the customer complaint or symptoms that steered you to this diagnostic direction?
Hi sorry for late reply. This motor came in with complaint regarding the DEC shift control. Motor was having issues coming out of forward gear (ultimately the failure was confined within the DEC system and harnesses and not main engine harness/sensors). We were checking voltages on the computer and noticed erratic reference voltage reads from several of the engine harness sensors. Yamaha usually specifies 5.00V reference for most of their engine harness/sensors, and we were seeing 4.95 to 4.98, so decided to take a look. The DEC problem was not caused by issues in the main engine harness, but I still wanted to publish this video just to show how sensitive these systems can be. Also, with older 4 strokes that still used three wire TPS like early 2000's F115, F150 and all 3.3 V6, engine harness/pressure sensor issues can cause major running problems if a water pressure/speedo sensor starts to misbehave from corrosion or connectivity issues. It throw reference voltage all over the range and then TPS voltage goes way out of spec which infuriates the ECU. Hell hath no fury like a dazed and confused ECU! One of the first things I check now with older F150 and 115 etc that has running issue and has also passed basic mechanical inspection (compression, manual shift check, gear oil and motor oil do not look like a milk shake etc) is to disconnect any sensor that has access to raw water such as speedo and water pressure while running the motor in the tank. If it miraculously starts to behave, it is likely dealing with engine harness voltage and corrosion issues. May still need a sync and link, but this step gets you close quick!
@@outboardst.comoutboardspec8631 First, Thank you for this detailed response. I'd love to see you go through these Diag procedures as you are an excellent instructor. With any modern engine auto/marine dealing with an "Infuriated ECU" (lol) will become more common as these engines and systems come under the control of the ECU and it's ever expanding family of control modules. The day is coming when the simple (better) engines retire and you'll be wearing a lab coat and pocket protector to fix them. I'm looking forward to seeing your channel and business grow. The tools you design and create will become industry standard must haves. Thank you and keep the content coming!
PS; Where's Part 2?
I are you conducting courses.i need to learn from you
Can it start when not in water?
This motor ran ok in all testing environments, but had an occasional rough idle, literally the only issue we could find was abnormal reference voltage