Misfire ? Cutting Out ?

[Tydogg]

Well hear i am AGAIN !! Im telling you guys this boat has been nothing BUT issues !!

So, finally got out on the lake last weekend . Im having a "misfire" or "cutting out" of power unload at around 4000 rpm . Idles ok and doesnt seem to have this issue at idle though it does idle low and sometimes dies . Take off and start getting up to speed and it dies out then comes back IF i lower throttle position . This is all i have done literally the week of taking it out

-new plugs
-new cap
-new plug wires
-new fuel filter
-completely drained the fuel tank and let it "dry" out for 2 days . There was gunk in the tank guessing from bad fuel .
-cleaned out fuel lines with compressed air before installing new filter
-added a fuel and injector cleaner to tank and filled with premium

When on the "fake lake" this hasnt happened .

Also has brand new exhaust tubes and mufflers were cracked . Repaired both mufflers .

Im lost at this and cant seem to think of anything that would cause the issue with everything replaced. Pulled the plus and looked at all of them after we got back from the lake , all are a light tan in color . I also cleaned the injector with cleaner and the butter flys prior to al the things listed replaced above .

I did read on a Malibu forum that someone had what they thought was the same issue and it turn out there prop was bent ....now my prop is NOT good (this is the way i bought the boat btw, looking at purchasing a new one shortly).

Anyone have anything they think i should look at or try ?? Thanks guys

[Mikes]

What boat and engine is this?

[zabooda]

My 98 never had many problems but twice in the 16 years I owned it my mechanic replaced the electronic ignition. The engine sporadically missing.

[Tydogg]

What boat and engine is this?

Indmar 5.7 EFI none LS1

[trayson]

ignition switch
ignition coil
Fuel pump(s)
Fuel pump wiring
Fuel pump relay wiring or relay socket


Some ideas to think about

[Tydogg]

ignition switch
ignition coil
Fuel pump(s)
Fuel pump wiring
Fuel pump relay wiring or relay socket


Some ideas to think about

The wiring i have checked and all is good . The fuel pump itself i have not checked the pressure however just assuming its good ( which assuming is not great ) and the only reason i say this is because i can put it on the fake lake and everything works perfect , throttle is super responsive not cutting in or out . Also had it on the trailer in the water and ran it for 20 plus minutes testing the exhaust hoses and mufflers , putting it at a steady RPM and leaving it there for a good amount of time with no issue . Only started happening when on full load . Ignition i have not checked either

[Branden967]

I second a fuel issue. Does it run fine up to 4000 RPM and then cut out after? If so sounds like it’s starving for fuel. Have you also checked the fuel filter?

[z28ke]

Did you replace the fuel filter before or after cleaning out the tank? If you replaced it before then I would go ahead and replace it again now that you know the tank is clean.

[Tydogg]

Shoot sorry guys left a reply last week and apparently it didnt post !! Anyway , changed the fuel filter AFTER cleaning the tank . And also after blowing the lines clear and lettting them sit . When i did pull the old filter the gas that came out was very very "rust" color with small black pieces in it . Thus thinking it was bad fuel so went about pulling all the fuel out of the tank , cleaning and letting dry .

It only cuts out at steady high RPM or sometimes will flat die if i give her the beans to start to pull . Btw this is all WITHOUT any ballast just the boats own weight and a wakeboarder .

So last weekend after all this , went and filled it with premium and wwent out . Did not cut out all day and ran perfect . Just this weekend , samething happened and started cutting out again .

You guys think possibly the Fuel Pump is starting to fail ? IF so thats odd because again checked pressure and everything seems to work perfect until under load

[Turbinesurgeon]

Probably a good idea to check fuel pressure at the rail



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