650 sn first ski

priest312

priest312

Location
Arlington wa
First post first ski. I bought a 91 sn 650 3 weeks ago. When I test rode it I really wasn't good enough at riding a stand up to properly evaluate how well it ran overall.

I've been chasing problems since I bought it, with a lot of help from all of your previous threads and posts.

My current issue is the ski has a major bog/hesitation when you pin it. It will actually kill itself if you pin it and don't let go. This happens at all throttle ranges except above 3/4. If you blip the throttle you can work it into the top end but once you get going wide open on flat water I can feel the ski start to slow a little and lose some power.

I've got 120 pilot 1 turn out
28psi pop off
135 main 3 turns out.

I'm ordering a wide range of jets today in hopes they arrive before the weekend. (None of the dealers around here stock the jets for mikuni sbn) I plan on going up on the pilot jet and re evaluating how she runs. I expect to end up with a 115-118 in it but I want to try richer before leaner.
Then once I have that dialed in I believe my main needs to be 1-2 sizes larger than it currently is.

Sorry for the long first post. I've been needing somewhere to sort my ski thoughts for a couple weeks now.

Oh yeah, it's got a protec exhaust and head on it, k&n flame arrester, riva groovy ride plate, a stainless prop of unknown manufacturer or pitch, and an a/m intake grate of unknown manufacturer (it looks similar to a buddy's pump stuffer intake but not identical, and an a/m -3" pole handle.
 
Mattyboy45

Mattyboy45

Just gonna point out a few of the smaller things you might not have checked. Clogged fuel filters, spark plugs, carb rebuild(diaphragm)
 
priest312

priest312

Location
Arlington wa
Thanks for the input. It did have a clogged fuel filter that was causing the ski to intermittently die last week but I have already replaced it. I put a brand new set of ngk b8es plugs in it (had b7es in when I bought it). I was told the carb was rebuilt the week I purchased it, but I have no real way to verify the rebuild as I didn't do it myself. It does look very clean inside an none of the rubber looks worn or brittle.
 
Larry

Larry

Location
New Jersey
Also check the fuel tank vent check valve.

+1 on the carb rebuild. It will at least eliminate that as the issue.

I feel your pain. I just picked up a 650 SN and cannot get the thing running right. My carb rebuild kit is in the mail.

Good luck.
 
priest312

priest312

Location
Arlington wa
The internal filter is a mesh filter on the fuel pump side of the carb, and that is the only internal filter correct?

I checked the tank valve and it seems to operate fine. It's not stock it's an a/m inline valve.

I took it out again today and now when I idle for an extended time through the no wake zone and shut it down. It is having a difficult time restarting. If I am out riding and fall off or shut it off it fires back up instantly. This seems to indicate a rich idle mixture but I am adjusting the idle mix screw as per the mikuni sbn manual. What else can cause hard starts after extended idling?
 
B

Boardmandan

I've got a similar issue with hard start after extended idling. I am going to try plugs and see if that helps. My 91 sn ski is all stock. Will post back if it helps.
 
priest312

priest312

Location
Arlington wa
I spent a little bit of time this weekend jetting and I've got the ski running much better but not perfect. I dropped the pilot to a 115 and it cleaned up my bottom end pretty well. I am still lacking up top, I will try going larger on my main when I get it out to the lake and find some flat water to tune it on.
 
priest312

priest312

Location
Arlington wa
Took the ski out today and got towed home.
It was running better and I was working on my subs, after a couple deep subs I noticed I wasn't bilging any water. I took it to back to the beach and ran through some seaweed on the way. Found that I had blown a fuse for the bilge and needed to ride around a bit to stock siphon the water out. First I need to get the seaweed out of my intake grate/impeller. I flipped the ski on It's right side and pulled the weeds out. Fired it off and made it 10ft. It would fire and as soon as I touch the throttle die.

The ski runs fine now after sitting for a few hours with the cover off. I also Have a k&n flame arrestor. Did I really cause all my own problems by dunking my flame arrestor under water?
 
priest312

priest312

Location
Arlington wa
I currently have a 115 pilot, 130 main, 28-30psi pop off, low speed 2turns out, high speed 2 turns out and she rips. Nice crisp throttle response down low. I need to dial my high speed adjuster in still but my jetting is close.

I have developed an intermittent dying issue now that I am trying to solve.
 
priest312

priest312

Location
Arlington wa
Ski starts up quick no problem. Ride for about 20 seconds then dies, cranks but won't start. Wait a minute or two and it will start but die quickly. When it dies it is sudden with no warning signs. Also sometimes when cranking it over after it does it will backfire and then start. This makes me believe I have a spark issue as opposed to fuel.

Possible electrical problems are:
Cdi box
Stator
Coils
Start/stop switch

I am going to try and duplicate the issue at home with a flush kit, then unplug the black and white start/stop wires and see if I still have an issue. If that doesn't solve it which should I look to next. I also have a vxr700 with a 61x that I can pull parts from to test if they swap with a 650. Also can anyone suggest a good service manual for the superjet.
 
Larry

Larry

Location
New Jersey
It still seems like a fuel issue, more specifically a fuel supply issue, but u have already cleaned the carb, changed the filter, looked at the vent and supply lines, next would be electrical.

Does it happen when the engine is both hot and cold?
I have a similar issue, but only when hot. Runs fine when on the hose or for 15 minutes in the water. Then it just stalls out when going to wot. Then hard to start.
 
priest312

priest312

Location
Arlington wa
I wouldn't say hot. It doesn't run long enough to get hot before it stalls. I'm going to put it on the hose this morning and if I can get it to stall I will check for spark immediately. I'll post back with my findings
 
priest312

priest312

Location
Arlington wa
So I go out this morning pull the plugs and verify spark on both cylinders, verify spark on an old 3rd plug. Put the plugs back in and clamp the 3rd to a bolt on the head. Start the ski let it run until it stalls. Pull the front wire put it on the 3rd plug and crank. No spark, keep cranking for a few seconds. Stop for 2 seconds, hit the button again and spark! And ski running on one cylinder. Stop, replace plug cap to spark plug in cylinder and repeat. I came up with the exact same result every time with either plug wire. I am indeed losing spark. I will now try disconnecting my start stop switch and jump the starter to try and eliminate the switch as the fault.
 
priest312

priest312

Location
Arlington wa
With the black and white wires from the start/stop switch unplugged the ski will start and run until I kill it (turn the idle down). With the wires plugged in it varies, sometimes 3-4 minutes, sometime 10-15 seconds. With the wires plugged in the ski kills itself every time. With the wires unplugged I have yet to have the ski kill itself.

The switch or wires to the switch are grounding out and killing the ski. I will swap my switch from the vxr and take it to the water. Hopefully I found my problem.
 
priest312

priest312

Location
Arlington wa
Took the ski to the lake today. Put almost a full tank through it without a single stalling issue. I had the black and white wire unplugged all day. So I am in the market to rebuild, or have a switch rebuilt.
 
priest312

priest312

Location
Arlington wa
I really didn't expect it either but I'm glad I can ride my sj again. Sitting on the beach isn't fun.
 
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