Should I go Backwards or Forwards???

[Matt_E]

Jared...he says he's getting fuel dribbling when the engine is not even running. I would think that rules out vibration (due to whatever)
I think he needs to take the carbs apart and make sure everything is where it's supposed to be.

 

[waxhead]

opps my bad i didnt see that
your right i think carbs apart
and figure out whats holding the n/s open
i wonder if the pivot arms are bent up to high

 

[93SJ760]

I think with increased pop-off from 20psi to 28psi which I did last night, I stopped the flooding while the engine is not running. I may still have the dribbling issue when I start it tonight (couldn't last night as it was too late). I did check pivot arms and they seemed to be in tight contact with the needle when it was all the way down. Also with the pop off gauge there is no leaking by the needle until it pops so that would indicate a proper seat. I guess just for some reason I was getting over 20 psi that was causing them to leak.

 

[Matt_E]

Even at 15psi popoff, the N&S should not leak if the engine isn't running.

 

[Mark44]

One thought. The ski is sitting in the sun and the tank pressure builds up kind of like your gas jugs sitting in the sun. The check valves on the pump side of the carbs are bad and allow the pressure from the tank and lines to pop the needle off the seat and leak fuel into the engine.

Just a thought.

Mark44

 

[93SJ760]

I'll rule out the sun as it was overcast all wknd and the machine does the same thing in the garage but ...

the check valves in the pump that may be a good thing to check.

My fuel definitely stops running when I release the pressure out of the tank. But should this matter? Isn't there a direct path for fuel from the tank to the needle and seat? I thought the check valves were only to stop back flow on the pump?

 

[waxhead]

i have been down to 12psi with out dribbling
the pop off pressureis not the issue
it may mask the problem but it sure will not fx it

 

[93SJ760]

I'd try 115 pilots, 120 mains, and 30psi popoff. Low screw about 1.125 turns out and high screw between 1 and 1.25 turns out.

I bet it would work well...

Mile,

Your bet seems to be pretty close. The machine is rideable now and responds well. I did exactly as you posted except for my mains are 125s for now until I get to tuning there and my pop-off is 28psi which I want to adjust higher until I get lean then I'll back off.

I'll need to use a 1.5N+S to go higher as I'm already using a gold spring in a 2.0 N+S.

I will also try to pull another screen out of my stock 44mm f/a's which should lean it out a little also.

The carbs are still flowing fuel as it sits there. When I go to take off it takes a while to clear out as the engine is full of fuel and it's loaded right up.

I noticed my exhaust tube is pretty tight against my breather holes on the carb regulator covers. Is this normal with 44mm carbs and a riva mani and spacer? Any ideas? Can I drill a 2nd set of holes up above the exhaust pipe?

 

[Matt_E]

You need to disassemble your carbs and solve that fuel leak. Any tuning is otherwise worthless.

 

[waxhead]

happened to me a few years ago
the spacer shoved my carbs up against my exhaust and i would full up with petrol as well
happened when i went from an riva to an r&d layback spacer
the fix was simple i drilled extra holes in the diapram plate

 

[93SJ760]

Thanks Wax!

My hose does seem very tight against the carbs so I'll drill an extra hole in each up above the exhaust hose location. Before I do I'd like to catch them dripping and try to move the exhaust hose away in order to verify that this is the issue.
I'm running the riva spacer and manifold with carbon fibre re-enforcement on the sides. I guess this all eats up space.

 

[93SJ760]

Problem fixed!

After drilling 2 new holes it's running a lot better and no more fuel dribble. Now I get to start tuning for real. It runs good now but I think I will keep going higher on my pop-off until it hesitates then come back a bit. The machine doesn't seem very snappy on the low end. Mid range is very arm wrenching. Top end I can't do until next week when my tiny tach arrives.

Any starting point recommendations for my brothers ski?
62T 701
Dual 46mm carbs
Vortex flame arrestors
Type 4 dry pipe
That's about it. Just don't know what to do about the big carbs on a stock 701 set-up.

I was thinking big pilots (120 - 125) and rather large mains also due to the lower air velocity. (110 - 115)

Any input?

Tyler