Super Jet Superjet low end bog

R

River Rat

Squarenosed
Location
USA
SmittySX said:



So my next question to the gurus is will this tiny leak cause the major low end bog?
Ill be tearing down and rebuilding as soon as i get new gaskets.
Click to expand...

I'm no guru but shouldn't the psi be dropping in your gauge? I'm sure the leak is worse when your motor is making more pressure then what you pumped in it.
-Pull the rear coupler off
-Turned that motor upside down and pull the bottom case off.
-Take a picture or remember how the seals came off
-Clean the matting surface but make sure u don't drop them inside and install new crank seals how they came off.
-spin crank bearings so they drop into the pins
-use 1211/ honda /yamaha bond to seal the cases
- Seal the starter area as well while your a it
- case 12mm bolt torque is 20 ft lb
- Bedplate 14mm bolt torque is 34 ft lbs

The job sounds hard but it's really cheap and good insurance to replace the crank seals and doing the job well, it's just takes a while to do.
Another thing you could do besides panicking when the motor runs on you while it's on the trailer by the water just back the ski back in the water and it puts a load on the motor and will shut off.
 
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IS0LD0UT

IS0LD0UT

I hate winter
Location
MN
+1 I flipped mine upside down and just replaced the seals. Its much easier than removing/replacing the cylinders and then splitting the cases.
 
Pro-pulsion

Pro-pulsion

Location
Ontario, Canada
I can relate to this, I had my ski run away a couple of times. Only after swapping out my intakes though and it was due to lack of fuel getting to the carb(s). Once enough fuel filled the system the ski was fine. My thought is that the fuel is draining down back out of the carbs causing the run away situation. The leak you have discovered does not appear to be the seal to me, it looks more like the sealant used on the case halves is the problem spot. As for the boggy throttle, again only my personal experience, but when I had my old XP800 I was going through this very thing. I tore down the engine after a full season of everything checking out only to find it was the crank bearings gone bad...very bad. What was happening was that when the ski was at idle, it would sound fine, when you pour the coal to it you would get all sorts of hesitations and rev limiter-like top end missing. The crank bearings were so bad that when the power was applied the crank would literally move up or down inside the bearing opening up an air gap between the crank and seal throwing the carburetion off totally. It was also so bad that when full throttle was applied, the mag cup would contact the stator triggering the battery light as to say there was an electrical malfunction. I bought new electronics for that thing like crazy until I finally found the real culprit. It could very well be the same scenario for you, crank bearings. If you plan to do new seals anyway, might as well go over the whole thing and make certain there are no other hidden surprises waiting to surface. The last thing you would want to see is a good ol grenading at any distance from shore all because you chose to skip putting that extra few hours into inspection. Plus you will at least know for sure what the condition inside is like and how well it was reassembled.
 
Dartman

Dartman

Location
usa
once you have your leak fixed
lower the popoff and use a bigger low jet
you have a lean studder problem
may have to drop the high jet a little as you fix the studder by richening the lows
 
Dartman

Dartman

Location
usa
is this a b pipe?
do you have a jetworks valve on the stinger feed?
do you have a restrictor or jet in it?
take out the jetworks valve and drill out a old needle valve to 7/32 hole
put that inline to stinger and try that as you can help a low studder by adding just a little more water to the stinger
 
SmittySX

SmittySX

Location
Cleveland, Ohio
Dartman said:
once you have your leak fixed
lower the popoff and use a bigger low jet
you have a lean studder problem
may have to drop the high jet a little as you fix the studder by richening the lows
Click to expand...
Again... Why would i start messing with the carbs if it ran perfect for me AND the previous owner...?
 
SmittySX

SmittySX

Location
Cleveland, Ohio
Dartman said:
alright just go ahead and change everything else out...stator, cdi, ignition coil, start stop switch, flywheel, etc.
Click to expand...
I wasnt trying to be a d!ck by any means.. I do appreciate anyones helpful opinion.

That was a legitimate question. Why would i mess with the carbs if it was running fine? Am i missing something?
 
SmittySX

SmittySX

Location
Cleveland, Ohio
Dartman said:
is this a b pipe?
do you have a jetworks valve on the stinger feed?
do you have a restrictor or jet in it?
take out the jetworks valve and drill out a old needle valve to 7/32 hole
put that inline to stinger and try that as you can help a low studder by adding just a little more water to the stinger
Click to expand...

Yes, im running a b pipe. No jetworks flow valve. I planned on running one when i reassemble.
 
jetpilot36

jetpilot36

Location
Fort Worth
SmittySX said:
I wasnt trying to be a d!ck by any means.. I do appreciate anyones helpful opinion.

That was a legitimate question. Why would i mess with the carbs if it was running fine? Am i missing something?
Click to expand...
something is malfunctioning. it could be the carbs. that's why some people suggest to mess with the carbs.
 
SmittySX

SmittySX

Location
Cleveland, Ohio
jetpilot36 said:
something is malfunctioning. it could be the carbs. that's why some people suggest to mess with the carbs.
Click to expand...
Yes, i understand that. Several people have mentioned carbs and i have replied with a question to that.
To me, in my head, it doesnt make sense that if my boat was running fine then all a sudden not, that the carbs would need rejetted? Maybe im wrong? I dont know. Thats why i questioned it. Im sorry if i sounded like an a$$hole.

Ill keep you guys posted on updates.
 
Pro-pulsion

Pro-pulsion

Location
Ontario, Canada
I agree with you on that Smitty, for the ski to go from no issues to sudden and immediate issues lends itself to being a component failure. You're not on the wrong track with that thought process, it is good, sound, logical thinking. The number one rule in diagnosing is look at the easiest and most basic things first. I am looking forward to reading what you find, keep at it good sir, you will figure it out.
 
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