94 vmax 600 running like crap, possible fuel pump issue?

shaggyzr2

shaggyzr2

Active member
Joined
Dec 26, 2011
Messages
1,920
Age
48
Location
Central Wisconsin
A friend of mine has a 94 vmax 600, the thing is doggy, can maybe get around 60mph out of it. The plug on the pto side cyl is a a dark brown to black color and dry, the plug on the other cyl doesn't have much color at all to it and is wet, the piston on that side has way too much wash and looks very wet. Both cylinders are getting good spark, both cyls have good compression, carbs are clean, reeds look good, not sure what could be going on here. is it possible that the fuel pump could be pumping too much fuel to one of the carbs? Anyone have any ideas?
 

choke cable, oil cable, carbs really arent clean, sucking air, pisspoor clutch conditions, and the list can go on.

personally i would confirm the condition of the choke plungers and the cable adjustment and take a good look at the condition of the fuel screw o-rings along with the correct orientation of the washers and springs.
 
Choke and oil cables were checked out, carbs were cleaned 2 times now, clutching is fine. The o-rings for the air screws look good. If it were sucking air wouldn't that cause a lean condition?
 
I tired switching plugs and wires around, didn't help. Needle and seat looks good, i also replaced the o-ring on the needle seats. Both plugs have a nice blue spark to them.
 
straight jetting, not sure what the clip position was. The sled ran fine last year. I'll have to see if the lines are long enough to swap.
 
shaggyzr2 said:
A friend of mine has a 94 vmax 600, the thing is doggy, can maybe get around 60mph out of it. The plug on the pto side cyl is a a dark brown to black color and dry, the plug on the other cyl doesn't have much color at all to it and is wet, the piston on that side has way too much wash and looks very wet. Both cylinders are getting good spark, both cyls have good compression, carbs are clean, reeds look good, not sure what could be going on here. is it possible that the fuel pump could be pumping too much fuel to one of the carbs? Anyone have any ideas?
Click to expand...


A wet spark plug is caused by - not sparking when it's supposed to, too much oil, too much fuel, no compression, plugged exhaust, any coolant.

Are you doing all the work? I ask because you don't want to assume any work not done by you was done or correctly.

I've never seen a fuel pump, pump more fuel to one than the other. You may end up with more fuel in one bowl vs the other but that'd be due to incorrect float height, leaking/stuck float, leaking needle and seat or o-ring. Those would also typically cause flooding at idle or after shutting it off.

It idles okay?

Guesses -

Loose or fallen main jet? (hey, it happens)

Bowl vent routed properly?
 
Last edited:
We thought maybe the exhaust was plugged so we put a different pipe on it, that didn't change anything. It ran good last season, the carbs were gummed up from sitting over the summer so we cleaned them twice now. It idles nice, it just doesn't run smooth when you get on it and doesn't have much top end. I was kinda wondering about the bowl vent.....
 
I read on here a couple of months ago about this same issue. Ended up being something with the main jet. I think he did say something about it fell. I don't know what that means though
 
You must log in or register to reply here.


Back
Top