F70 spudders

[SNOOKDLB]

My 2015 hpxv2  occasionally spudders with running.   It stalled once and had to reprime the ball to continue.  I took it to my local dealer and 100 plus dollars later they could not find the problem.  

Any suggestions out there?     

[hawg]

I've run a Yamaha F115 and an F40. Both of them have had the same problem, causing them to sputter and occasionally stall. In my case, the engine fuel filter (the filter you can see with the cowling removed) has a hairline crack in the top of the black plastic casting which the filter cup screws into. The crack originates at the point where the stainless mounting bolt is cast into the plastic of the upper assembly. The crack occasionally allows air to leak into the fuel line resulting in intermittent stalling. The easiest way to check for this is to remove the cowling and have someone pump the primer bulb while you look at the top of the filter assembly. If it is cracked, you will see fuel seeping out from the crack. After replacing one of these assemblies on each of my engines, I started placing a rubber O-ring between the filter housing and the metal bracket to which it attaches. The O-ring absorbs some of the vibration, which I believe causes the crack to begin with.

[SNOOKDLB]

I gave it the check this am,  unfortunately that was not the problem.  I did notice the ball goes soft after about an hour however.  not sure if thats the norm or not.  Thx for your suggestion

[ChrisB]

You need to T a gauge and some clear tubing into suction side of your fuel system. Run motor under load no air bubbles and 4 inches of vacuum or less on gauge is what you want to see. You can also go run the boat with a portable tank to help isolate the problem to the boat or motor fuel system.