- Location
- New Jersey
Is water getting into the engine? When is boggs, pull the plugs and see if there is any chocolate milk inside.
Ski runs like crap when the tank is full, but it runs better when empty?
- Thread starter Roseand
- Start date
Water in the tank .remove all fuel to the point of completely empty ,and start with a fresh tank full .this symptom will feel as if it may be electrical ,cutting out ect. easy way to rule out water is to remove the gas in the tank, and if it isn't you can check that one off in a troubleshooting process of elimination .
Doesn't really feel like cutting out, after first it's absolutely terrible running condition witha full tank, then it's just lack of power(75%) and then by the time it's almost empty, it runs almost perfect. I'd think it would run worse when the fuel level is low if there was water in the tank since it'd be more concentrated.
What I was getting at was do we have any combustion leaking into the cooling circuit. I know you recently did the engine so I wouldn't expect it.
Have you been in contact with your supplier and let him know the issue maybe he has a suggestion, with jetting and what not since he supplied yours ?
I bought my jets from JM and sent my cylinders to be bored by PHP, and I did everything else myself..
The only things I've done since it was running great:
Fixed waterbox & rerouted cooling..I got about 4 hours of hard flatwater riding in with it running pretty much perfect. When I took it out to the other lake with big boat wakes, more inversions, etc, that's when this consistent problem started occuring.
What would cause combustion leaking into the cooling circuit? Blown O ring that goes between the dome and cylinder sleeve? It's just so wierd how it clears up a little after an hour/when the fuel level is low.
The only things I've done since it was running great:
Fixed waterbox & rerouted cooling..I got about 4 hours of hard flatwater riding in with it running pretty much perfect. When I took it out to the other lake with big boat wakes, more inversions, etc, that's when this consistent problem started occuring.
What would cause combustion leaking into the cooling circuit? Blown O ring that goes between the dome and cylinder sleeve? It's just so wierd how it clears up a little after an hour/when the fuel level is low.
So it all started after the water box failure and repair or new cooling routing? If that's true your ski ran fine prior in the bigger wakes you've mentioned?
Have you had a chance to inspect the box internally for loose intermittent blockages?
Also what about removing your head pipe and putting it on the water hose to verify your spray and no odd sprays/cracks
How is it adjusted, won't cause your issue but are you closed bottom and middle and open 3/4 top?
How much compression does it have now
What's the deal with water pressure, pull out those restricters you have and see if any changes occurs
You'll prolly have to only put a gallon of fuel in after you completely drain it and see if the low fuel/fuel level is at play or just a coincidence
It could very well be fuel or ignition/electrics like you mentioned
Have you had a chance to inspect the box internally for loose intermittent blockages?
Also what about removing your head pipe and putting it on the water hose to verify your spray and no odd sprays/cracks
How is it adjusted, won't cause your issue but are you closed bottom and middle and open 3/4 top?
How much compression does it have now
What's the deal with water pressure, pull out those restricters you have and see if any changes occurs
You'll prolly have to only put a gallon of fuel in after you completely drain it and see if the low fuel/fuel level is at play or just a coincidence
It could very well be fuel or ignition/electrics like you mentioned
- Location
- Ontario, Canada
You have redone the carb yeah? When thinking about this a little bit further the thought started to surface that as the fuel level gets lower, there is more room for the fuel to splash around. When the fuel splashes it creates higher concentrations of vapor pressure. The added pressure is helping to push the fuel through the lines. So perhaps the issue is not too much fuel or water which I believe is reasonably diagnosed out of the prospects, but rather lack of fuel at the start. With a full tank, the engine's only form of supply is by the pulse circuit and signal generated through the carb. When the tank pressure increases, the pulse signal doesn't have to be as crucial because the tank pressure is working equally to push fuel through the lines. Have you changed out your lines recently? If so did you go with larger lines? By going larger from the typical 1/4" you will reduce pressure. You gain volume in fuel but volume is not as important as pressure to get it there. A 3/8 line would require a good bit more pulse to draw the fuel through the lines when compared to 1/4. If you have the original lines still or at least original diameter, look further into the fuel delivery system. Check to make sure there are no line leaks at all connections, this also means checking how tight the securing devices are. If you use gear clamps, they might have backed off, zip ties need a load of tension to seal properly so the hose doesn't swivel on the inlets, and spring clamps lose tension surprisingly easily. Any of these conditions that allow the hose to be swiveled on the inlets will also allow air to enter or fuel to seep out.
Check the fuel pump portion of your carb too, compressed air is great for drying up residual fuel but if you have the carb apart anyway, take a single strand of bicycle brake cable and push it through as many of the tiny ports in the carb that you can find. There might be something partially blocking a port somewhere that air just can't take care of. One other last thing in mind at the moment, if your carb had the fuel return circuit drilled out then the carb is not holding enough fuel and running out too quickly, try running a restrictor in the return line. If I remember correctly, my Lamey carb needs an 85 pilot installed into the return line to keep proper carb pressure and fuel capacity in the pump. Without it, the carb runs out too quickly and then you have a lack of fuel supply and no power. The added tank pressure helps to force the fuel into the fuel pump on top of the pulse signal helping to keep the needed fuel volume in the carb. You could also just try slipping a small Robertson screw driver into the pulse hose fitting on the cases to make sure there are no obstructions going down into the cases reducing signal.
Check the fuel pump portion of your carb too, compressed air is great for drying up residual fuel but if you have the carb apart anyway, take a single strand of bicycle brake cable and push it through as many of the tiny ports in the carb that you can find. There might be something partially blocking a port somewhere that air just can't take care of. One other last thing in mind at the moment, if your carb had the fuel return circuit drilled out then the carb is not holding enough fuel and running out too quickly, try running a restrictor in the return line. If I remember correctly, my Lamey carb needs an 85 pilot installed into the return line to keep proper carb pressure and fuel capacity in the pump. Without it, the carb runs out too quickly and then you have a lack of fuel supply and no power. The added tank pressure helps to force the fuel into the fuel pump on top of the pulse signal helping to keep the needed fuel volume in the carb. You could also just try slipping a small Robertson screw driver into the pulse hose fitting on the cases to make sure there are no obstructions going down into the cases reducing signal.
- Location
- central florida
For those in the US: Robertson screwdriver has a square tip, not popular here,
A little more info I guess, but I've thought it irrelevent since it was running so good on flatwater...I found my waterbox messed up because I had to replace my stator- was adjusting rpms with a tach on a riva cdi that I was putting in, and my starter relay slipped and grounded out on the ebox, completely frying the ground wire off the stator. Needless to say I got a used stator, and used my modded protec CDI instead. I don't know if it took a tole on my coil, since this doesn't seem like normal bad coil symptoms. Like I said, it ran nearly perfect on flatwater after I replaced the new stator.
Carb was rebuilt by me with genuine mikuni parts. Everything's been working great for 70ish hours. Lines are 3/16 tygon(new line this year), so it's a super snug fit to get them on the fittings, and then ziptied. I've seen people not even use anything to hold 3/16 tubing on since it's a snug fit.
The return is not drilled out as it's just a stock 44mm SBN that came on my 95 square.
Thank you for that awesome response propulsion..I really appreciate it! Got me thinking now.
Carb was rebuilt by me with genuine mikuni parts. Everything's been working great for 70ish hours. Lines are 3/16 tygon(new line this year), so it's a super snug fit to get them on the fittings, and then ziptied. I've seen people not even use anything to hold 3/16 tubing on since it's a snug fit.
The return is not drilled out as it's just a stock 44mm SBN that came on my 95 square.
Thank you for that awesome response propulsion..I really appreciate it! Got me thinking now.
I bought 49 full spec "good and ready to go" turns out the throttle shafts were worn out I had .020 up and down shaft movement and worn out butterfly's 
I bought Lamey cast stroker cylinder and rad crank only 8 hours of use ready to go with new forged pistons.... Turns out crank was twisted out of phase 1/2 inch and cylinder bore was worn so with new pistons had .007 clearance. Needed bore and oversize pistons true and rebuild weld crank
I bought Lamey cast stroker cylinder and rad crank only 8 hours of use ready to go with new forged pistons.... Turns out crank was twisted out of phase 1/2 inch and cylinder bore was worn so with new pistons had .007 clearance. Needed bore and oversize pistons true and rebuild weld crank
For me this type of information is critical, before this it was good and after this incident/repair it's bad, it helps narrow the field down
It makes me wonder if somehow the shortage messed with the coil..Otherwise it could possibly be a fuel issue..it's just super wierd haha. Wanna get this figured out before the lakes freeze over. Planning on sportporting my cylinder, but I'd like to have it running right before I start messing with it again.
Joker
...chaos? Its Fair!
- Location
- La Porte, Indiana
Didn't you advance the timing? Or did you just ask me if I think you should do it?