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BF150, 2006, Will not maintain RPM's

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mirage2521

New member
Hello all, looks like a prettty good forum here. I hope there is some guru out there that can help me diagnose this issue. My motor sat up for about a year, maybe 18 months. I changed the HP and LP fuel filters changed the water sep. before taking her for a spin.

Everything seemed fine, left the marina, brought boat up on a plane, took time and let the motor warm up the brought her up to full throttle. It ran fine at full throttle for about 1 minute the began to run rough and would not hold RPM's. If I slowed down to half throttle or so she runs fine. SHe iddles great, starts first try but will not hold speed for over a minute. Once she does it the first time, if I try to come up in speed again the rough running starts right away and she never comes up. The fuel in the boat is about 20 gallons of 18 month old fuel and 30 gallons of new fuel. Do any of ya'll have any ideas?
 
OUCH! 18 month old fuel! That's a disaster waiting to happen, no matter how well it may have been treated.

Simple things first. I assume no alarms are going off, since you did not mention any, and your green oil light is on while underway.

1. If you have an external fuel-water separator (which you should have), drain or replace it.

2. While underway, open your gas filler cap and see if that clears up the problem. If so, you have a clogged breather tube to your tank.

3. While underway, at the point where power is stalling out, check your pump up bulb. If flat, you have a partially clogged pick up tube in your gas tank.

4. Run a clear plastic line from your pump up bulb to your onboard fuel water separator and see if you are getting any air bubbles in it while running.

5. Drain and check both your on board fuel-water separator and low pressure fuel filter.

6. Drain your VST. The VST is in place to assure an adequate amount of non-turbulent fuel is available to the high pressure fuel pump. (The fuel in the VST tank is kept under pressure to prevent vaporization, thus preventing the fuel from becoming too lean under variable demand.)

7. If that all fails, then drain your fuel tank completely, and start all over with new fuel.
 
chawk_man said:
OUCH! 18 month old fuel! That's a disaster waiting to happen, no matter how well it may have been treated.

Simple things first. I assume no alarms are going off, since you did not mention any, and your green oil light is on while underway.

1. If you have an external fuel-water separator (which you should have), drain or replace it.

2. While underway, open your gas filler cap and see if that clears up the problem. If so, you have a clogged breather tube to your tank.

3. While underway, at the point where power is stalling out, check your pump up bulb. If flat, you have a partially clogged pick up tube in your gas tank.

4. Run a clear plastic line from your pump up bulb to your onboard fuel water separator and see if you are getting any air bubbles in it while running.

5. Drain and check both your on board fuel-water separator and low pressure fuel filter.

6. Drain your VST. The VST is in place to assure an adequate amount of non-turbulent fuel is available to the high pressure fuel pump. (The fuel in the VST tank is kept under pressure to prevent vaporization, thus preventing the fuel from becoming too lean under variable demand.)

7. If that all fails, then drain your fuel tank completely, and start all over with new fuel.
Click to expand...

I have replaced all the filters. The rest sounds like great advice and I am going to try. My big concern was a blocked water passage and the motor overheating but I thought that would cause an alarm.
 
Yep - overheat will set off an alarm. Buzzer will be continuous, and the red overheat light will come on. Engine will shut down in about 20 seconds. Once you get all this straightened out, send an e-mail to me at [email protected] and I will send you a procedure for adding a water temperature gauge to your engine.
 
If you are at full throttle, the overspeed limiter may be kicking in. If you clear up all of your fuel issues and the problem still persists, try backing off full throttle slightly to see if the problem goes away. The limiter on my BF150 kicks in around 6200 rpm.

JLB
 
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