madman2021
Petty Officer 2nd Class
- Joined
- Dec 17, 2010
- Messages
- 175
Little background on the motor. Sorry it's a long post.
Purchased it as a demo motor in 2019 with 7 hours on it. Did nothing but oil/filter, fuel/water separators, spark plugs, and water pump. Have 97 hours on it. Motor is out of warranty now. In 2021 I installed a yamaha fuel management gauge and sensor (sensor was used). First trip out the motor would fall on its face after 4400 rpms. Read the sensors are notorious for plugging up. I don't usually run that fast so I put the replacement off for another time. Went fishing for the first time this season. Used my 100 gallon steel transfer tank with 6 month old fuel in it to fill the boat. Made it a few miles out and motor killed. Dumped the in boat fuel separator out and was full of rusty water. Dumped that filter and the one on the motor at least a dozen times throughout the day. Made it home, siphoned out the rusty water from the bottom of the tank, purged the fuel lines replaced both filters. Next weekend go out same issues. Dies about every 10 minutes. Check the filters, perfectly clean fuel. Later in the day it wouldn't go over 1400 rpms without killing and having to wait 10-15 minutes for it to finally restart. Would only run for 5-10 minutes at a time before killing again. Limped 4 hours home this way. Once home, replaced both filters again, replaced all fuel lines, removed inline fuel management sensor. Tested boat for a quick run down the bayou and back about 15 minutes @ 4500 rpms and ran great. Next morning go fishing and make it 10 minutes at 3500 rpms and dies. Limped it to a close fishing spot a few miles away at 1200 rpms. On the way home couldn't get more than 800 rpms without killing immediately. Ran on/off @ 800 rpms for 2 hours. Ran 5 minutes, killed and wouldn't restart for 10 minutes. Repeatedly this process for 2 hours. Pulled boat out the water and removed the VST tank and disassembled expecting to see rusty water or clogged VST filter. All perfectly clean. Zero particles on the VST filter. Only other thing I can think of is the low pressure pump being weak? I don't have an inline primer bulb on my boat so wasn't able to pump a ball to see if the issue went away. Ball went bad and I removed it and never replaced cause the motor always started fine without it. I'm unable to find this low pressure pump on any parts websites. It's on the diagram but there's no number Next to the part. Could there be something else I'm missing? All my maintenance and replacement parts are always OEM Yamaha except my in boat filter which is WIX.
Purchased it as a demo motor in 2019 with 7 hours on it. Did nothing but oil/filter, fuel/water separators, spark plugs, and water pump. Have 97 hours on it. Motor is out of warranty now. In 2021 I installed a yamaha fuel management gauge and sensor (sensor was used). First trip out the motor would fall on its face after 4400 rpms. Read the sensors are notorious for plugging up. I don't usually run that fast so I put the replacement off for another time. Went fishing for the first time this season. Used my 100 gallon steel transfer tank with 6 month old fuel in it to fill the boat. Made it a few miles out and motor killed. Dumped the in boat fuel separator out and was full of rusty water. Dumped that filter and the one on the motor at least a dozen times throughout the day. Made it home, siphoned out the rusty water from the bottom of the tank, purged the fuel lines replaced both filters. Next weekend go out same issues. Dies about every 10 minutes. Check the filters, perfectly clean fuel. Later in the day it wouldn't go over 1400 rpms without killing and having to wait 10-15 minutes for it to finally restart. Would only run for 5-10 minutes at a time before killing again. Limped 4 hours home this way. Once home, replaced both filters again, replaced all fuel lines, removed inline fuel management sensor. Tested boat for a quick run down the bayou and back about 15 minutes @ 4500 rpms and ran great. Next morning go fishing and make it 10 minutes at 3500 rpms and dies. Limped it to a close fishing spot a few miles away at 1200 rpms. On the way home couldn't get more than 800 rpms without killing immediately. Ran on/off @ 800 rpms for 2 hours. Ran 5 minutes, killed and wouldn't restart for 10 minutes. Repeatedly this process for 2 hours. Pulled boat out the water and removed the VST tank and disassembled expecting to see rusty water or clogged VST filter. All perfectly clean. Zero particles on the VST filter. Only other thing I can think of is the low pressure pump being weak? I don't have an inline primer bulb on my boat so wasn't able to pump a ball to see if the issue went away. Ball went bad and I removed it and never replaced cause the motor always started fine without it. I'm unable to find this low pressure pump on any parts websites. It's on the diagram but there's no number Next to the part. Could there be something else I'm missing? All my maintenance and replacement parts are always OEM Yamaha except my in boat filter which is WIX.