yammi 150 4 stokes keep shutting down

[Frank S.]

cant put my finger on this problem but my 2005 2530 twin 150 yamahas keep shutting down when trolling or just throttling up. Both port and stbd shut down but never at the same time. the fix is i just pump the fuel bulb and it restarts then is fine for while. but it seems to be happening at an increasing rate to the point of several times on a single trip. any thoughts?

 

[Riding High]

Just to cover the bases, when you pump the bulb is it soft and squishy at first and then get firm? If so maybe your primary filter is plugged? Have you changed your primary and engine mount filters?

 

[akholmes]

slew of things it could be.

I'd start with filters & mechanical fuel pumps if it was me

 

[DaleH]

I'd start with filters & mechanical fuel pumps if it was me

If both draw from the same tank, I'd start with the tank or fuel system 1st. It could be a blocked or partially clogged anti-siphon valve (ASV), note they appear just like a std barbed fitting, but it is in the insides that they differ. They use a SS ball bearing and spring to prevent fuel from dumping into the bilge, if the fuel line broke between the tank and F/W separator:

See here: viewtopic.php?f=8&t=292

But it could also be the pick-up(s) from the tank themselves. They extend off the boss that sits on the top of the fuel tank, where the ASV (above) connects. Check and remove your fuel pickup up out of the tank, by using 2 box wrenches 180-degrees apart. 'Lint' will build up in the tank and is prone to clogging the end of the fuel pickups in rough waters.

Some pickups have fine mesh screens on them - some do not. Your choice, if there and you use ASVs - then I'd keep the mesh screen on the pickup.

 

[shawnee83]

Just a thought but my tank has 2 pick ups on it. I assumed it was for running twin engines. I you are just drawing off one you could just replace your ASV and at the same time move it to the other pick up on the tank. Kill 2 birds with one stone. Did it to mine chasing an issue last year. Turned out to be something else but was able to rule out ASV and pick up at the same time. Good luck.

 

[Brent]

Is the fuel primer bulb installed up side down? Is the fuel out end pointing up to the sky or vertical. Is the bulb a POS or a good one?
Like Yamaha or Merc


A portable fuel tank connected to motor will separate motor from tank issues quickly

Remove cowling and look at fuel filter for water and debris
YAMAHA has a see through bowl

Dozen other possibilities

 

[Frank S.]

to all of those that replied, thanks for your input.