Loss of power while surfing

[Garetth]

Hey guys I'm at a complete loss and could use some suggestions. I have a 2005 23lsv with the 383 hammerhead.

Boat runs amazing and has plenty of power but after surfing for about 45 minutes it will start to sputter and pop when trying to get up to speed. If I empty the ballast and slowly cruise it will run. So far I've changed the following with all BRAND NEW parts 

Fuel filter twice to make sure, fuel regulator, fuel pump. 52psi on keyup, 60 psi while running.

Also changed the distributor, cap, rotor, ignition module and ignition coil - set into service mode and set timing to 10°.

Brand new BPR6EFS plugs gapped to 0.045, 8mm spark plugs wires, thermostat, water impeller, ECU water temp. Removed every water like and checked for blockages ~ transmission cooler had a bit of crud in there that I cleaned out.

Then I checked for fault codes with a DIY LED flasher for the Mefi 4 and had a 34(low voltage map) and 81 which seems like there could be a bunch. So I changed the MAP sensor and TPS sensor. Took it out today and exact same thing - after about 45 mins of surfing it looses power and can't get to speed and just bogs. I tried removing the intake filter, leaving the engine cover open and removing the fuel fill cap to see if that helped and nothing did.

 

Checked for codes again after and it's showing no codes... Can any one think of anything else?

[JeffK]

Could the ecm or something else be getting too hot and failing?

[formulaben]

Did you use plenty of the included heat dissipating grease when installing the ICM? 

[Garetth]

34 minutes ago, formulaben said:

Did you use plenty of the included heat dissipating grease when installing the ICM? 

I replaced the entire distributor so it was already installed 

[Garetth]

53 minutes ago, JeffK said:

Could the ecm or something else be getting too hot and failing?

I mean it's not impossible but I would think the ECU would completely fail once it got hot. And I can still cruise around when the issue starts happening 

[Garetth]

Just wanted to update this post for the future of anyone runs into the same issue.

 

I checked my fuel pressure again and found it would 60psi steady and then once it started surging it was actually dropping to 15-20 then back to 60. I had already installed a new fuel filter, fuel pump and regulator so I knew that was good. It ended up being the anti siphon that's threaded into the tank fuel pick up. Once the boat for hot for some reason the ball would get stuck slightly and the pump would cavitate.  Replaced this and now everything is good. 

[JasonK]

Wow that's crazy. Now we know to check that.

[EchelonMike]

Thanks for updating the fix...I have a similar boat and similar vintage so will file this one away for future help!