There's a fairly good chance your impeller pitch is not accurate to what it is labeled as, but it sounds like you bought someone else's problems. Start with the CDI, check your stator as said above and possibly try a new impeller. Nobody can tell you anything honestly about the porting from those pictures.
- Location
- native idahoan
It's gonna be something electrical, bet its that poopty WSM cdi and stator to match..........In my fixed steer sj I run the same impeller in a 144 pump. For the engine I have a oem 760. 180psi. Single 46. B pipe.....in 8 seasons of riding a sj it's my favorite all around motor yet. Have no issues clearing the ski out of the water at any given moment.
Sent from my SM-S767VL using Tapatalk
Sent from my SM-S767VL using Tapatalk
waxhead
wannabe backflipper
- Location
- gold coast
Personally I would want to know how you b-pipe is setup. If thats not right it will kill the crap out of your engine
- Location
- Ontario
I've did a bit of work on the ski. Msd ignition, 9/15 hooker, rebuild pump, fcv, oem stator, change waterbox to stock superjet also changed the restrictive exhaust hose. The good news is the motor has lots of power. It's running great I have a little bit of tuning in pipe. I only have bottom open a 1/4. And it's getting to hot. Having a hard time setting the fcv to open when I give it throttle on the trailer. The only issue I'm having now is that randomly sometimes when I'm off the throttle and corner the ski has a heavy bog delay. I can clear it by holding it wide open. I have a carb rebuild kit so going to do that. Just didn't know if there is anything else I should be looking into?
Good that your heading in the right direction .a little tip is not to make too many changes at one time ,because if you do correct an issue you will not be sure of the cause or what fixed it .the prop is where i might have started (the 13/17 sounded tall) but its great that you eliminated that and cleaned up electrical gremlin possibilities .dual carbs is where i would be looking next. running one carb is great for tuning and are really good for a surf platform even freestyle ,but if your trying get flatwater "snap" running a single is like cutting one of your motors balls off .
DylanS
Gorilla Smasher
- Location
- Lebanon Pa
I ran a bored over 760 that someone had raised the exhaust ports pretty bad with a b-pipe/dual 44’s/62t electronics and despite my port timing worries it still hit hard on the bottom. Actually surprised me. Hell right now I’m running Lowell race ported cylinders on a different motor and it hits like a freight train off the bottom. Not saying that port timing isn’t vitally important, but it takes a lot more to really kill your bottom end than you think IMO. Personally I believe that your exhaust chamber setup and stinger diameter make the biggest difference. Anyways, I’m going to dig around to see what size prop I was running on my setup. It seems like the general consensus is too tall of a prop. Either that or you have a rich condition on the bottom/water ingestion that is killing your bottom end.
- Location
- Ontario
I'm happy with how it runs in the mean time. If i can cure that random low end bog. Hopefully carb rebuild and tuning fixes it.
DylanS
Gorilla Smasher
- Location
- Lebanon Pa
Sorry! Just read your post above this one! What I bet you are experiencing now is a rich condition caused by low pop off pressure. When you have it pinned and let off the throttle there is a excess amount of fuel being dumped by your Venturi ontop of your butterflies, then when you open her up again the motor is fighting to clear out that sudden excess fuel. Try increasing your pop off pressure a few pounds. Bet that would clear it up but you might need to do some carb tuning after that.
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- Location
- Ontario
I only rode it for about 5 minutes. It's runs strong lots of low end snap. Coming out of a couple spins it was a complete bog almost like it's loading up and floading. Not every time though randomly. I changed the waterbox from tdr to a superjet. Don't know if I need to look at jetting.
- Location
- Ontario
This sounds very accurate in what it is doing. Thanks for the advice.
- Location
- Charlotte, NC
Try opening the top screw on the headpipe 1/2 turn out. The closer the water injects into the exhaust stream, the more effect it will have on the engine performance. To a degree, the cooler the exhaust chamber, the more bottom end snap you will have but can sacrifice top end power. It can be a trade off. When I setup a ski with a bpipe, I'll run a separate line into the bottom of the headpipe with a tee, bypass and flow control valve on the outlet. I start on the headpipe screws at 1/2 turn on top, 1/4 turn on bottom. On the bypass I put a small piece of 1/4 I'd fuel hose inside of the bypass line to act as a restrictor to slow water flow a little. This also puts more pressure on the control valve that allows it to open. Will also affect how the headpipe screws spray water into the exhaust. I like a separate cooling line to the pipe because it allows better control of pipe temps which more power can be found doing so