How to diagnose and fix water in fuel - 2000 SN GT-40

[MaineMan]

I would love any input you may have on the following mechanical issue I am having with my SN 2000 GT-40. I think that it may be water in the fuel. Here is what is going on:

1) I started the boat on the ramp and it barely started and idled very rough with several backfires. It would eventually stall.
2) There was not a strong fuel smell which makes me think that the system is starved of fuel rather than flooded.
3) I have not started my boat in 3 months, it has been sitting with 3/4 tank of untreated E10 gas (I have been running past few years with E10, reluctantly, but no problems until now).
4) The fuel filter is over 1 year old and due for a change
5) I am not a mechanic!

I am wondering if anyone has any thoughts on strategy at this point. Here are my ideas:

1) When I returned home I immediately ordered a new fuel filter figuring that, at a minimum, I would drain the FCC and change the filter.
2) After draining the FCC and changing the filter, should I just start it up to see if it runs okay?
3) Should I drain and replace all the fuel right away, or wait until I determine if changing the fuel filter is sufficient?
4) If I need to drain the fuel, has anyone done that in a Nautique? Any suggestions on the best way to do that?

Thanks everyone.

[Quinner]

1 year old filter should be fine, most likely you are dealing with bad fuel, try adding some seafoam with some fresh fuel, preferably non-ethanol or the highest octane you can find

[glassywaters]

I would check fuel pressure first. There is a connector on the fuel rail and FCC, but you need a fuel pressure gauge. (Harbor Freight works)

Engine idling 31 +or- 3 psi
Key on engine off 39 +or-3 psi (may take a few cycles of key off/on to get there)
Once fuel pressure has been established it should hold and slowly creep down (1-3 minutes).

[MaineMan]

glassywaters : Thanks for the reply. Do you happen to know if the GT-40 has schraeder valve connectors for this test? I've never done this before (I don't keep my boat at my house to easily check). Is this the type of gauge that I would use? http://www.amazon.com/Actron-CP7838-...ct_top?ie=UTF8

Also, if fuel pressure is low, what would you probably do next?

I saw this thread too, looks like it could be relevant (although no mention of what the ultimate solution ended up being)
http://www.planetnautique.com/vb5/fo...r-acceleration

[glassywaters]

There are two. One on the fuel rail and one on the fcc. Fuel gauge looks good. You can also listen for the fuel pumps to prime, the low pressure fuel pump is the small pump connected to the fcc (large canister/high pressure pump). You can also check the fuel pressure relay on the back of the engine. Fuel relay and low pressure fuel pump are common problems.

[MaineMan]

Guest / glassywaters ,

Success. Thanks for your help. I drained the FCC and it was 60% water. I left the drain open and had my son turn the ignition on and off to pump fuel through the system. I collected the fuel in a jar until it was pure fuel and no water coming out. I all, I removed about 1/2 gallon of water/fuel mixture. I replaced the fuel filter (the old one was filthy), added 2 cans of Seafoam to the gas tank, filled it with non-ethanol gas that I just discovered is selling at the local Wawa, and now everything is running fine. Skied yesterday with my boys.

I've heard that after using Seafoam that it is a good idea to do an oil change and change the spark plugs. Any opinion on that? I'm going to do some research to see if that matters.

[Quinner]

Thanks for the update, great when the fix is cheap and easy!! Never heard that about seafoam, kind of sounds like BS but who knows, let us know if you find any validation.