Need help with flooding issue

Hey I have 2003 Supra Launch SSV. Indmar Assault MPI. It is having some flooding issues and having a hard time figuring out how to solve the issue. It starts and idles perfectly. If I can get it out of the hole shot it will run perfectly. Its just that initial power surge that seems to flood it. I just changed the Cap, Rotor, and plugs hoping that would help but it is not. It is producing quite a bit of black smoke which also leads me to believe it is flooding. Attached is a video of the startup and run. You can see once its revved it give a little hesitation, but then will run fine. But you will also notice considerable black smoke and at about the :21 mark in the vid you can actually see the black running out of the exhaust. Any help would be greatly appreciated. I am not very mechanical so any description of where things are or how to do would be greatly appreciated. Thank you!
http://youtu.be/wKIxpzgNeVo

First I am not real familiar with which system you have . I would start with the fuel regulator on the fuel rail it should have a vacuum hose going to it . Pull that hose off and see if there is fuel there if there is change the regulator.

I would start with fuel pressure.

May sound crazy but a lean condition can cause what you describe.

If a cylinder or two is to lean to fire the unburt fuel will go out the exhaust and look like you a running rich.

I agree with Mike Hunter on the stringer material. Any composite decking material youmwouldnget form Lowes or Home Depot is strictly for non-structural use.

You're water source isn't very good either. (most is running on the ground under the boat) Make that tighter to the hull so that water is pumping out the exhaust the entire time.

I am in the process of diagnosing the hesitation on take off at full throttle.

Went to autozone and bought a fuel pressure gauge to connect to the shrader valve, then I will be able to determine if there is enough fuel getting pumped, or if it is electrical issue.
On ours, when it was dumping fuel, I changed the throttle position sensor. It would just dump fuel like you say yours is doing. That is $90 part and simple to change.
http://www.skidim.com/prodinfo.asp?number=R020040

Looking at the throttle body (under the flame arrestor (air filter looking cap), on the right side (port side in boat terminology), if you look, there is a semi circle looking component with (I think) 2 wires coming out.

To put the new one on, you would disconnect the throttle cable so you can move the lever manually, open the butterflies all the way (pull lever toward bow) and then slide the new on back on, since the rod should line up with the slot in the TPS. Then tighten the screws back on and reconnect the throttle cable.

5 min job. Look at the head of the screw and you will see that you need a different wrench to remove them. (torx bit I believe * looks like astrisk on tip) Can be found at any hardware store. I bought a variety pack so I knew I would have any size in the future. They are in the drill bit dept and fit into a rachet with a 1/4 socket for easier turning than a screw driver.

jzelt,

great description. Is there a way to tell if that is the problem for sure? Or is it just simple enough to do so just do it to rule it out. Or are you saying get the fuel pressure gauge and check like you did? And lastly wear is the shrader valve. Thanks for the reply.

I don't know of a way to test it.
Where I found my info to try it was this link.
https://forum.supraboats.com/archive...hp/t-1005.html

I have the gauge to try to determine where another issue lies. (Bog/dieing on wide open takeoff, but ease into throttle works).
It will show me if there is enough fuel pressure throughout the RPM range.
If not, then I will replace the fuel filter, retest and then look at the fuel regulator, then fuel pump.
The schrader valve is located under the black plastic cover over your flame arrestor.
Follow the fuel line off the front of the throttle body toward the fuel pump on the starboard side, you will see a black screw cap.
Unscrew that and you will see a tire pressure looking valve.
The gauge I bought ($40) screws onto that and will allow you to monitor the pressure as needed.

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Originally Posted by hawk22

Hey I have 2003 Supra Launch SSV. Indmar Assault MPI. It is having some flooding issues and having a hard time figuring out how to solve the issue. It starts and idles perfectly. If I can get it out of the hole shot it will run perfectly. Its just that initial power surge that seems to flood it. I just changed the Cap, Rotor, and plugs hoping that would help but it is not. It is producing quite a bit of black smoke which also leads me to believe it is flooding. Attached is a video of the startup and run. You can see once its revved it give a little hesitation, but then will run fine. But you will also notice considerable black smoke and at about the :21 mark in the vid you can actually see the black running out of the exhaust. Any help would be greatly appreciated. I am not very mechanical so any description of where things are or how to do would be greatly appreciated. Thank you!
http://youtu.be/wKIxpzgNeVo

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now you say u cant get out of the hole with out it shuttering and puffing black smoke?
Is there any hesitation at any point? What Thottle body do u have / engine? When u first take it into gear and then apply throttle does is bog?
If u floor it does it bog? ?

@ lively, yes it hesitates coming out of the hole shot. In idle it is perfect. In the first gear (the one that engages movement) it is perfect. But if I go to give it a lot of throttle to pull someone out it will bog down and stutter, sometimes die. If I can ease it past the bogging and get it on plane, it runs fine. 5.7 indmar 325hp, mulit port injection.

Electronic fuel pump?

Change ur filter! ! Every 10-15 outting! May seem extreme but look at the enviroment its in ...

U have to verify fuel pressure on the water and running the same way u discribed .. what happens is if u have trash in your tank that then gets sucked through the pick up into engine ... but it is the pumps job to maintain 32 lbs of pressure no matter what .... so buy a gauge and check it! If u have the correct pressure then u have a vacuum issue causing more air and not enough fuel ( leaning) not rich ... check those out and report back private

changed fuel filter. emptied the old one into glass jar and no signs of water or anything else. A tinytiny bit of sediment, but nothing notable. Checked fuel pressure with gauge. 40 to start. Throttled dropped to about 35 then back up to 40. Cleaned MAP sensor. No change in behavior. Where are these vacuum lines you speak of?

Can someone tell me what this is? is this a vacuum line? or fuel return? Just noticed it had a crack, but it appears to just be painted and the paint is cracking. The rubberish tube seems fine, but just curious if this is anything I am potentially supposed to be checking... looking specifically at the center of the pick the top hat looking thing...Attachment 10160

That is the fuel pressure regulator
Yes that is a vacuum line

I don't know the system you are working with but fuel pressure should go up as vacuum goes down.

This weekend, I disconnected the TPS since it was idling normal. The fuel then increased dumping and the RPM went up to 1100 (normally 5-700). I guess this is one way to test, but I don't think you will find yours increase in volume since it is already dumping fuel.

So frustrated....I finally broke down and took it into the shop. They told me there are 2 fuel pumps, evidently one is cheap and accessible and the other is buried in the fuel housing to supply the injectors. It's a $340 part, plus about 4 hours of shop time to diagnose, install, and lake test afterwords. Well, I'm kinda stuck so I had them do the repair. Only to get my boat back on Friday. Put it in the water on Sunday to finally enjoy summer and the same problem still exists!!! I'm really frustrated because I know the shop is just gonna say, "well it must be something else, but the fuel pump needed done anyway." Just dropped over a GGRRR in that boat and it doesn't work like its supposed to... Sorry...Venting! I haven't heard from the shop yet so this is my only outlet.