New member and owner

[EasternNC]

Hey folks I'm hoping to find some expertise here to help me on my 06 DF175...

I bought it abandoned from a marina for cheap. I know NOTHING of its history other than it sat for at least 2 years, and the marina started it 4 months back. I know it has a hole in the exhaust housing stb side. I just got the thing running an hour ago. It was pouring fuel vapor out the hose from the head cover to the intake when trying to start and while running, it still blows vapor out just not as bad as it was. The plugs were fouling terribly so I had to pull them many times and clear either cylinders by cranking without the plugs in place. Finally after some perseverance...

I gave it some gas and after clearing the cylinders really good, put it back together, and got it to fire. It ran well it sounded like... I went down to idle and it cut off. Then restarted it just fine with some throttle. I went up on power and the engine would only surge, but not gain much rpm. I backed down on throttle again and it quit. Restart easily this time at idle. Went up on power again, still surged. I checked for water flow, and didn't see any pee coming out, wasn't sure where to look, none out the exhaust either. It was a total of 4 maybe 5 min run time max. Now as my engine cools its crackling like broken glass. This sounds expensive. Is my motor toast now? If not, what could make it surge like that? I even put it in gear and it still just surged, shaking left and right every time it went up and down on power. Other than that, it sounded strong and smooth.
If I can get it to restart after its cooled down a few hours, I will buy a water pump for it. But if I just cooked this damn thing like a bone head, then I will scrap it, and move on.

[EasternNC]

Well, I got it to restart and ran if for a minute with no problem, so I dont think I hurt it none. Thats good..Now I just need to figure out why at 3k rpm it surges power in gear and in neutral. Also, the rpm light comes on when it surges.

[Moonlighter]

There is a neutral throttle switch on the gear linkages. Its role is to send a signal to the ecu when the engine is in neutral that prevents the engine revving past about 3000 rpm. its like a race car with the pit limiter on it surges and farts !

If.that switch is broken then the ecu wont know the engine is in gear and wont let it rev. Its a simple Inexpensive switch you may find it and check it, could just be loose too.

The idle stalling issue could be a few things - there is an idle air control valve that controls idle speed and if its stuck then similar symptoms to your description. Search this forum for IAC issues you will find some info.

It could also be fuel related, the thing you mentioned about fuel pouring out a hose - the engines have a VST that has a needle and float, again search this forum, it that VST is durty inside, gunked up, then the overflow hose will have fuel dripping out instead of vapor. Solution =clean out VST, check needle and seat, reset float level to spec. Its probably worth doing this on an old engine thats been badly neglected anyway. And always run a water separating fuel filter in the line between tank and engine to prevent future contamination.