2008 Yamaha 250 Low Pressure Fuel Pump

[KWAJR0B]

Blew fuse (5A) going to low pressure fuel pump, replaced, same thing. Decided to replace low pressure fuel pump, everything looked good (engine ran, did not bog down for 10+ minutes, then shutdown. Once again, fuse blown. Against my better judgement, installed a 10A fuse (which is shown in the electrical diagram in the shop manual (but oddly not on the fuse box on the engine (5A)). Started up and immediately had fuel pouring out (turned out to be fuel line connected with a coupler above the VST had separated)). Once fixed, installed 5A fuse, started engine with no issues, ran at 1500 RPM, seemed good, checked fuse and once again blown.

Against my better judgement (again), I installed the 10A and this time fuel came out the bottom of the cowling.

Not sure where to go from here? Do I have a block somewhere? Did I reverse polarity when installing the pump? Is the pump drawing >5A but <10? and causing the pump to run at too high a pressure?

Obviously not an expert here, any suggestions (other than taking to my local Yamaha dealer (I live in a very remote area)).

 

[Fishtales]

I'd shoot a message to SIM Yamaha and see if he can point you in the right direction. Buy the part(s) from him so you can reach out in the future.

 

[seasick]

Are you referring to a low pressure pump on the motor or an external 'lift' pump?

I am confused that in one case the motor ran fine but after you shut it dow, you checked the fuse and it was blown. I might think that a motor mounted pump with a blown fuse would cause the motor to shut down.
By he way, swapping the fuse for a higher capacity can result in serious issues. Some bad results could be damaged ECU, burning wires or even a fire. Granted in your case swapping in a ten for a five is not extreme, if the wire size is small enough, the extra current could result in over heating

 

[DennisG01]

Are you referring to a low pressure pump on the motor or an external 'lift' pump?

I am confused that in one case the motor ran fine but after you shut it dow, you checked the fuse and it was blown. I might think that a motor mounted pump with a blown fuse would cause the motor to shut down.

I was waiting on some more clarification, too, as it was a little hard to follow exactly what did/was happening. Rob?

But, to your question, it's possible that the time the engine was "running fine" was less than the amount of fuel in the HP VST "tank"...

 

[KWAJR0B]

I'd shoot a message to SIM Yamaha and see if he can point you in the right direction. Buy the part(s) from him so you can reach out in the future.

Forgot all about Andy at SIM, used him a lot when I had a smaller boat. Just ordered the Candopro Yamaha Diagnostic tool from him, hoping that may shed some light on the issue and probably a good thing to have in my toolbox.