scorpion engine 315h.p dies after 15min.

[RACER52]

I need some help. I have been trying to fix our ski boat with no luck
ITs a sanger v-drive with the 315 scorpion engine 1997 850hrs
the engine dies after running for a while(approx 10-20min) it runs perfect till this happens. you can feel it start to cough or miss and can definatley
see it in the tach(fluctuates) then the engine flat shuts off.
I thought it was fuel, so I replaced the fuel pump. started and ran fine and went for a test ride. 4800 rpms no problem then same chiot. Tach flutered and shut off.
So this weekend I replaced the distributer module. same thing, this time it ran for 30min then shut off.
note: the engine will refire after sitting for a little while and run perfect, then wamo=dead
I have not put a DDT on it, I will try to aquire one.
any thoughts would be greatly appreciated.
Its the wife's boat and its been down 4 weeks. She already said if it was my boat it would have already been fixed. (she's right but wtf)
Racer :hammerhea

[spectras only]

You didn't mention replacing the water separator filter.

[victorfb]

floats may be sticking shut. when it dies, have you tried looking to see if fuel is coming through the carb? sounds like a fuel issue.

[572Daytona]

fuel filter, clogged fuel vent, sediment in gas tank are other possibilities to check

[75spectra]

With that engine being EFI you really need to get it on a scan tool to find out whats going on. It could be something really crazy like a sensor. I have the HP-377 Scorpion in my Eliminator and its a killer engine. Mine is 370 horsepower!

[victorfb]

ok, had no idea it was EFI. dont i feel stupid now. :cry:

[Cole Sanger]

Could it be the coil getting hot?

[tbanzer]

When it dies cool the coil down with water or ice and see if it restarts.

[paradigm shift]

Yep other than running a scan I am thinking coil. I have seen this happen exactly as you discribe many time. Let us know what you find out. Have you check for spark after it dies?

[celeb1]

I had a bad coil and it acted the same way you are describing it.

[75spectra]

This Engine should have the Delco EST distributor in it, this uses GM's "E"core coil that generaly will not be affected by heat (its not liquid filled). I have seen the pickup coil inside the dist. fail and cause similar symtoms. Witout checking, (cant remember) this engine might also have a fuel pressure switch? The scan tool is the best way to save time and money. It will eliminate most of your guesswork. Please let us know what it is....

[NuckinFutz]

I doubt it would cause it to quit like you're stating, but the 315 Scorpion engine has both the water separator filter and a second inline filter located by the raw water pump. I had fuel trouble with the inline filter once on my Centurion and replaced it. My boat would never quit, but I could tell something just wasn't quite right. Good luck finding the filter though, it looks just like the filters on GM autos, but the fittings are slightly different and most Mercury dealers just look at you stupid when you tell them you have a Scorpion and need the inline filter.

[RACER52]

sounds like a Scan tool is what I need. I just talked to a buddy who will loan me one. I guess a couple filters wont hurt either. They were replaced
this year. I did not check the fuel vent yet.
I didnt think the coil could be the problem since its not liquid filled
I will post when I run the scan tool.
thanks for all the input.
Racer

[bigkatboat]

It's the same filter that some of the 4.3 V6's use, instead of a water trap. I have seen many Merc. EFI motors go down for this same reason. Start with the filter, then go to the DDT. Some builders are using this inline filter BEFORE the water trap and they are going down in under 50 HRs run time. PS, also check the filter used on the HP 525, it's the same.