Thread: Scratching my head on my 780
09-02-2012, 11:20 PM #1
Scratching my head on my 780
Pretty much stock except I have the Flame arrestors from a 95 SLX on there. After I replaced the fuel lines, updated the carbs, and tuned them in, it was running great; beautiful piston wash. However, it was barely keeping up with my 750's. The hull was taking on too much water, so I checked things out a bit closer. The exhaust manifold gasket was compromised, and leaking water out the top on the CEN jug. Simple; replace it. Well, when I was replacing it, I noticed that both starboard motor mounts were shit. So...I replaced the motor mounts. Also, while I was doing all this, I added pissers. Yeah, yeah...say what you want, but I think they're cool...lol.
So I hit the lake today. P.O.S. I felt like this thing was gut-shot; wouldn't plane...couldn't get past 4400 rpms.
When I troubleshoot, I usually follow a distinct path that has never failed me: Fuel, ignition, compression, propulsion.
Fuel: I didnt' change anything from prior to now.
Ignition: Same as above
Compression: All cylinders 120-125.
Propulsion: The pump is in PRISTINE condition.
Prior to the repairs, I started with stock settings on the carbs and had to tweak them very little to get performance and piston wash. So, it's tough for me to accept that I tuned the carbs excessively to a compensate for a motor that had a bad exhaust manifold gasket and broken motor mounts. Were that the case, I would have been re-jetting to compensate and would have had the "WTF?" moment were it that extreme.
Anyways...thanks for staying tuned this long. I know I'll eventually figure it out, but if anyone has thoughts on where I need to be poking around, I'd really appreciate it.
09-03-2012, 12:03 AM #2
- Join Date
- Jul 2007
- near Toronto, Canada
Just because you didn't change something doesn't mean it is actually good.
Review what you are sure is good, just to confirm it actually is. Ignition, timing, plug wires, plugs, etc. Carburetor hoses, pulse lines, etc.
09-03-2012, 12:35 AM #3
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