Maybe Air ?

[1fs23454]

05F150TXRD
Recently changed the water separator filter and the fuel filter on the engine. Ran the motor in the driveway for a while and yesterday went out for sea trials I guess you can say because I also replaced the impeller for the water pump.
Anyway, squeezed the ball, fired right up. But, seemed to be running a little rough. So, I figured probably air and kept going. The engine did smooth out some but, when I wanted to bring the speed up was very sluggish and could not reach WOT which has never been an issue after I changed the prop several years ago. The bast I could get was 4k out of 6K easily.
Then the engine would just drop to about 3k and a few seconds later ramp back up to around 4K.
Not finished yet. I decided to shut it down and just do a quick check around for anything obvious. No obvious issues found so, start it back up. Nope. Had to squeeze the ball again.Pumped it up good and it fired right up but, still, rough.
The gas has been in there with stabilizer for about 6 months or so. Smells ok.
i can only think that there,s air in the lines since I replaced the hoses going to the water separator and then to the fuel filter bowl.
Any suggestions as to what the problem could be? There's never been an issue.
Thanks in advance.
Fred
05KW186CC f150TXRD

[TownsendsFJR1300]

Did all the running issues begin AFTER your service or was there issues before?

(I gather the engine sat for 6 months, no use? What stabilizer brand did you use?


First thing I would check is the under cowl fuel filter. As you probably saw, it turns yellow, expands and is a PIA to often fully seat. Make SURE it is INDEED FULLY SEATED.

The other fuel filter, I gather the seal surface is nice and clean (no corrosion-air leaks).

If both check out, hook up another small 6 gallon tank with fresh fuel. Also, drain the VST (on the starboard side) and catch what comes out looking for crap.

Those fuel lines would have vented out any air that may have been in them..

[rodbolt17]

my thought is your gonna clean the VST,replace the VST inlet filter and flush the injectors and dispose of that old gas.
adding new gas to waste fuel means simply more waste fuel.

[boscoe99]

my thought is your gonna clean the VST,replace the VST inlet filter and flush the injectors and dispose of that old gas.
adding new gas to waste fuel means simply more waste fuel.

Any time that milk in the reefer spoils I simply add fresh milk to make it all better.

Gotta go. I am off to see my doctor. Been having stomach aches. Don't know why.

[pstephens46]

6 months of sitting not good. Stabilizer will not protect the gas for that long. I am not sure if Stabil actually does a damn thing... Especially if is ethanol.

[TownsendsFJR1300]

6 months of sitting not good. Stabilizer will not protect the gas for that long. I am not sure if Stabil actually does a damn thing... Especially if is ethanol.

My K100 and Gas Shok WILL keep fuel GOOD for well over a YEAR, closer to TWO YEARS (it was Non-Ethanol-89 from the marina)...

I've documented it myself, pulling two year old fuel out of my tank (when I had a bad spark plug-thought it was fuel). Fuel smelled/looked new, neighbor ran it in his boat / car, myself in the SUV-NO issues.

Stabil, IME, is junk, had varnish in a small engine carb WITHIN a MONTH (after cleaning spotless)...

[1fs23454]

I ran the boat about a month before chaging out the filters and replacing some of the fuel hoses without any problems. Ran perfect as always. The fuel in the filter is clean. I emptied it and disconnected the hose from the tank to the filter, pumped the ball to get about a gallon out of thebtank. The gas was clean and smelled like gas. No chunks either.

[1fs23454]

I'm back. Went out this morning with a new 6gal tank and fresh gas. At low RPM (2500 or less) no issues. Runs smooth. Add more power and can only get max 4300 RPM on a motor that has always been easy to reach WOT at 6K plus a couple. Bogs down at the higher RPM load beginning around 3200 RPM.
Any suggestions? It's definitely not the gas. And, since I connected the portable tank at the bulb, it's not anything prior to the bulb since the symptoms have not changed.

[walleye1]

Injectors need done and rite now mister.

[99yam40]

clean everything VST , filters ,and injectors included

[walleye1]

That is a no brainer.

[rodbolt17]

and while you have the VST apart check the grommet between the pump and the housing.

[1fs23454]

Good info. Will take care of it this weekend. Thanks but, 1 other question.
Since removing the VST tank is a pain, as long as I have it out and apart, should I go ahead and change the pump? It''s not that I like to spend $ but, I hate doing something twice which wastes more money. The pump is expensive but, also close to 900 hours on the motor.
Also, I never answered the question about the stabilizer I use. Sea Foam.

[walleye1]

Sea foam is not a good stabilizer, it is more of a cleaner.

[99yam40]

it is for removing carbon deposits from what I have read,

as far as should you replace the pump, I would inspect it to see if water has got to it and rusted before buying a new one.
running it dry might hurt it also