2002 Yamaha 150 OX66 Fuel Problems

jb1

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Months ago HP fuel pump stopped running. First time, never happened before. ECU fine. Mjuch trouble shooting before taking terminals (red and blue wire) off pump, cleaned them. There was a white grease inside each rubber cover cap that had coated the terminals. Thought it was causing the terminal not to make good contact w/ the terminals of the pump. Reconnected and motor ran fine. Ran for about an hour and motor died. HP fuel pump not running. Took terminals off pump out in the water, re-installed and motor ran fine.

Thinking its losing connection, I put a small SS flat washer under each wire terminal lug. Ran this time for about 50 minute and the fuel pump quit again.
Pulled terminals from pump loose out in the water and re-installed, pump would not run. After waiting about 15 minutes pump starting running.

Is it a bad up? Does pump have internal pressure switch to shut it off so as not to overpressur fuel rail? Could it be the pressur switch? Or is it just the terminal causing a bad 12VDC connection? Really lost for thing to do next. Don't want to spend all the money for a new HP pump and thats not the problem.
 

rodbolt

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Re: 2002 Yamaha 150 OX66 Fuel Problems

do you have a voltmeter?
that white grease is a dielectric grease,helps keep corrosion down,
 

jb1

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Re: 2002 Yamaha 150 OX66 Fuel Problems

Yes, have a voltmeter.
 

jb1

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Re: 2002 Yamaha 150 OX66 Fuel Problems

When everything is installed, there was voltage on the wire terminal lug but not the posts of the pump. That lead me to think bad connection. And improving the connection from the lug to the posts of the pump was the issue. There is a very small shoulder on the pump post that the wire lug is supported by.
 

rodbolt

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Re: 2002 Yamaha 150 OX66 Fuel Problems

anytime the key is on the red lead has 12V dc between it and ground.
the ECU controls the pump ground via the blue lead.
below about 1200 RPM the current path is through a resistor mounted on top of the throttle body after that its straight back to the ECU bypassing the resistor.
voilia a two speed pump.
 

jb1

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Re: 2002 Yamaha 150 OX66 Fuel Problems

Do you know if there is a pressure switch internal in the pump? Must be so as not to overpressur the rail. Any reports of this acting up and stopping the pump?

Thanks
 

rodbolt

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Re: 2002 Yamaha 150 OX66 Fuel Problems

no pressure switchs.
pump has 12V anytime the key is on, ECU completes the ground path to make it run, below 1200 and the path is through the resistor above 1200 and the path is back to the ecu.
 

jb1

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Re: 2002 Yamaha 150 OX66 Fuel Problems

Just curious because when the key is turned on but not start, the pump runs for a second then stops. So this only happens when the motor is not running. If the motor is running (below 1200 rpm) the pump runs with out stopping?

Thanks
 

rodbolt

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Re: 2002 Yamaha 150 OX66 Fuel Problems

on that motor at key on the pump runs for a few seconds, if the ECU doesnt get a pulser coil signal indicating the flywheel is moving it turns off.
once running the pump always runs or the engine wont.
if the engine stalls for any reason the ECU is supposed to shut down the pump.
below 1200 it runs on about 9V due to the resistor in the ground path,it reduces operating current and amperage,above 1200 the ground path is routed to an ECU internal ground bypassing the resistor.
 

jb1

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Re: 2002 Yamaha 150 OX66 Fuel Problems

Have you ever heard of the pump stopping then after a few minutes running again?
 

rodbolt

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Re: 2002 Yamaha 150 OX66 Fuel Problems

yes, if the pump is failing and draws more than about 6 amps the ECU drops it.
 

jb1

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Re: 2002 Yamaha 150 OX66 Fuel Problems

Thanks much Rodbolt. Well the pump will not run now. So maybe with help I can determine what's wrong. With Key on I get 12VDC on the red wire to ground. What do I check next?
 

jb1

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Re: 2002 Yamaha 150 OX66 Fuel Problems

Pulled the fuel pump out of the housing. Powered it from a 12VDC source. Sometimes it ran sometimes it did not. Looks like a new fuel pump is in order. Any ideas on the place with the best price?????
 

jb1

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Re: 2002 Yamaha 150 OX66 Fuel Problems

Changed to new pump, problem fixed. Took old pump apart.

Quite surprised to see that the armature / commutator / brush assembly is immersed in the gasoline/oil mixture. So all brush / commutator wear material gets ingested / combusted in the engine. The fuel is pump from the bottom of the pump assembly by a small pump plate around the amature and brush assembly out of the top of the motor.

Oh well probably not uncommon today, but I would not have designed it that way.
 
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