Primer bulb not staying hard

[kk4iz]

we have a 2006 HPDI 250, the primer leaks down while we are fishing, it has not been long that we replace the bulb with a after market. Was hoping that would fix the bulb from leaking down. Running at WOT it feels like it is falling off the pad but no horn going off. We had all the filters and plugs changed.

[yukongt]

I would look at the low pressure fuel pumps.

[STLBassBuster]

^^^^^ & I would not trust any aftermarket part on my Yamaha. Boats.net etc can you parts fast.

[jethro1]

In use a primer ball will not normally be hard. Why, because the lift pumps are drawing fuel to the motor by creating low pressure in the primer ball.

With an HPDI there is little if ever any need to use the primer ball.

[ifishinxs]

[QUOTE=yukongt;7644480]I would look at the low pressure fuel pumps.[/QUOTEh

this is the answer. Your low pressure pumps are bad. That explains why your bulb won't get hard and why your falling off at high Rpm's. Sims Yamaha has what you need and it's an easy job.

[Bass AHolic]

toss 1 of those little Blue Pills in gas tank

[Charles Prestridge]

It is a good time to install an electric fuel pump and eliminate the primer bulb and the low-pressure pumps.

Do a search for electric fuel pumps.

[Rich Z]

Unlike on the ox66, lift pumps on hpdi motors seldom fail. The arrow on the primer bulb should be pointing upwards while priming and it should be mounted that way also. This will prevent fuel evaporation and air from getting trapped in the primer bulb.

[kk4iz]

I have always had to prime the bulb since day one but the boat came with an after market blub from Xpress. just got worst in the last few months. The arrow is pointed in the right direction. Will pickup a Yamaha bulb in the morning

[Charles Prestridge]

You will still need to check the low-pressure pumps.

Unbolt the pumps, pump the bulb and if fuel comes out the back of the pump, it has failed.

[Charlie206]

I have always had to prime the bulb since day one but the boat came with an after market blub from Xpress. just got worst in the last few months. The arrow is pointed in the right direction. Will pickup a Yamaha bulb in the morning

If you have had to prime an HPDI from day one, you have had a problem from day one. They don't need or require priming under normal circumstances. I very much doubt the primer bulb is your problem.

[kk4iz]

Primer bulb did not fix it. So I put the boat in the shop this morning..Could not get no more than 5200 rpm at wot, acts like it was not getting all the gas it needed. Too d*** hot here to be working on a motor, if it is too hot to fish it's too hot to work on a motor

[One fat one]

I had that problem I had to replace the anti siphon valve on the tank everyone told me it was the vent but the valve was stuck I just put a regular fitting on it mainly cause the original was aluminium

[kk4iz]

Just got some info from my mariner that the boat mfg. did not put a check value or some kind of value on the pickup tube. My fuel line was coming apart also. We will know more later this afternoon. Computer gave a good report on motor,no codes. Compression check good,

[TOXIC]

If you have bad fuel lines then you better go ahead and have a full filter replacement while you are at it. Might be a good time to send the injectors off to Rich as well.

[kk4iz]

Just had all High and regular filters along with plugs changed, a complete service and checkup. We had put Atwood?? fuel lines and bulb on a year ago from Wally World (don't like that place) the thin inter liner was not breaking up but separating and pulling together and acting like a value. Motor runs great now, no problem even holds the front end up or should say it stays on the pad or on plane at lower speeds, I had forgot it did that, been acting up for a long time.I guess we had been fishing with our buddy too much in last few years, he had got a new boat and wanted to use his most of time