200 EFI, idles great cold. Can't keep running later in tournament day.

[bbarthelt]

Hi all. My 1996 200hp EFI on a 1993 Nitro 2000DC, serial number 0G361511, was the subject of a longer post recently. The mechanic took apart the fuel injection system and it was rusted to hell and many parts were seized with varnish. Mechanic rebuilt it, and my prior problem (power cutting off around 4000 rpms, and when hitting bumpy water) was finally fixed.

On to the next problem: Every time I go out the pattern is the same:

Start the engine cold, she fires up beautifully, idles perfectly in neutral, sounds smooth and happy, and when it's time to go she takes off like a scalded cat and runs like a top.

But...throughout the tournament day as I go from spot to spot, the engine seems to need more and more throttle to start, and RPMs drop until she dies if I idle in neutral. The problem gets progressively worse throughout the day. By the time the tournament is over, I can barely keep it running long enough to get it in gear. As long as it gets throttle it keeps running.

I'm hoping this sounds familiar to the experts on this site. Any suggestions on what to look at are greatly appreciated. Thanks in advance.

[CatFan]

Have you replaced every inch of fuel line with ethanol resistant line? Changed the fuel filter? Looked inside the tank for crud?

[bbarthelt]

Have you replaced every inch of fuel line with ethanol resistant line? Changed the fuel filter? Looked inside the tank for crud?

1. Fuel line replaced entirely
2. New fuel filter
3. Have not checked in the tanks (there's 2) for crud.

[bbarthelt]

One bothersome thing: i've used marine sta-bil religiously with every addition of fresh gas. I'm bothered that this didn't save my fuel pump system.

[kls2020]

Run motor on a portable fuel tank with new good fuel and see if there is a difference to eliminate the fuel tank being the source of the problem .
The TPS and port side temp sensor work together to adjust fuel mixture from idle thru midrange . A bad electrical connection will only gets worse as the motor gets hot so check all wires tight and corrosion free.

[JOE54]

excessive smoke when it does start when hot ?????

[SilverFox579]

Pumping bulb before every engine start?

[bbarthelt]

Joe54: YES...only in the later starts, smoking excessively when starts.

SilverFox579: At first no, but I did start doing this...ball is always soft, needs pumping when cold (obviously), but later, I've checked it and it's always already hard....I pump it anyway.

Thanks guys. Your knowledge in this forum never ceases to impress me.

[bbarthelt]

Sorry to pry: @ Joe54, what does smoking excessively when warm indicate? Thx in advance.

[JOE54]

fuel leaking into mtr that shouldn't be /flooding symtoms very rich condition

[bbarthelt]

Thanks Joe54. Do you think it would be related to the job that was just done to rebuild the fuel pump system, or should I be barking up another tree. And now that you mention it, when this happens I smell fuel.

[JOE54]

yes sir very possible, fuel spilling over into plenum same as flooding(rich rich rich) hard to start, excess smoke poor idle, take it back its yo money

[bbarthelt]

Thanks Joe54 and all. Will be taking it back.