Earlier this year I rebuilt a 1996 gti. I replaced all the grey fuel lines with mpi marine grade fuel injection lines, completely rebuilt both carbs with parts from osdmarine, rebuilt the fuel baffle (float sensor was not floating), replaced fuel selector, replaced fuel pressure check valve, and all filters inline (both in fuel separator and carbs).
I've had the ski running flawlessly for a few months now. My carb tuning is pretty much identical to the book. I believe i went with a 1/8 turn deviation to lean each carb on the low speed screw side of things. A few days ago I was gunning it across the lake and felt the engine just die. I let off the throttle a bit and the engine came back. At that point I just let the engine idle for a minute or two, testing short bursts of throttle for a few seconds each. I slowly punched the throttle to 1/2 and just kept climbing to find the problem location. Somewhere around 3/4 to full throttle it happened again. Engine ran fine at that position for a few seconds, maybe 5-7 seconds, then just tried to die. I kept trying this over and over trying to figure out what it might be, never letting the engine die. I would sometimes decrease throttle and keep going or just return to idle. I was pretty far from the location I launched from, but was able to get back there without the engine dying (took me about 30 minutes).
I figured it might be spark plugs fouling, so i cleaned them with gas and a propane torch. Was able to get them clean that night, so I took the ski out the next day. Same issues as before. I was able to leisurely stroll around the lake for an hour or 2. Just couldn't go full throttle for more than 5 or so seconds without the engine trying to die.
I had an issue previously where I had a leak in the exhaust pipe that caused a spray that was getting sucked in by the carb months ago. I hooked the ski up to the hose yesterday and started it to verify this wasn't the case.
At this point I figure the issue is that I'm not getting enough fuel to the carbs at full throttle. I imagine what is happening is I am sucking air somewhere, and its most pronounced at full throttle. I've ordered part #17 from the fuel system diagram, as I remember reading that the fuel separator is one of the common areas where air might be getting in. Now that I think about it, I never replaced this o ring when rebuilding the fuel system. When i unscrewed the fuel separator bowl I did see some particulate at the bottom of the bowl.
Any idea what could be causing this?
I've had the ski running flawlessly for a few months now. My carb tuning is pretty much identical to the book. I believe i went with a 1/8 turn deviation to lean each carb on the low speed screw side of things. A few days ago I was gunning it across the lake and felt the engine just die. I let off the throttle a bit and the engine came back. At that point I just let the engine idle for a minute or two, testing short bursts of throttle for a few seconds each. I slowly punched the throttle to 1/2 and just kept climbing to find the problem location. Somewhere around 3/4 to full throttle it happened again. Engine ran fine at that position for a few seconds, maybe 5-7 seconds, then just tried to die. I kept trying this over and over trying to figure out what it might be, never letting the engine die. I would sometimes decrease throttle and keep going or just return to idle. I was pretty far from the location I launched from, but was able to get back there without the engine dying (took me about 30 minutes).
I figured it might be spark plugs fouling, so i cleaned them with gas and a propane torch. Was able to get them clean that night, so I took the ski out the next day. Same issues as before. I was able to leisurely stroll around the lake for an hour or 2. Just couldn't go full throttle for more than 5 or so seconds without the engine trying to die.
I had an issue previously where I had a leak in the exhaust pipe that caused a spray that was getting sucked in by the carb months ago. I hooked the ski up to the hose yesterday and started it to verify this wasn't the case.
At this point I figure the issue is that I'm not getting enough fuel to the carbs at full throttle. I imagine what is happening is I am sucking air somewhere, and its most pronounced at full throttle. I've ordered part #17 from the fuel system diagram, as I remember reading that the fuel separator is one of the common areas where air might be getting in. Now that I think about it, I never replaced this o ring when rebuilding the fuel system. When i unscrewed the fuel separator bowl I did see some particulate at the bottom of the bowl.
Any idea what could be causing this?
