Super Jet Been chasing this issue for too long... Advice?

San Diego SN

San Diego SN

Location
San Diego
The last two times I have hit the water with my single carb, protec built, 61x square, it will run great for 20-30 min then it will suddenly begin to starve for fuel at 3/4 to full throttle.


1st ride Issue: The first time, after it running great for 20-30 min, it bogged down and died during a WOT run which nearly threw me over the bars. After that it ran crappy. It would bog/stall at 3/4 to full throttle, also the idle wasn't strong and it would bog at first with a blip of the throttle. With the choke on I could keep it running so clearly it was running super lean.

What I did to fix it: Fresh mikuni rebuilt kit on carb, brand new needle and seat (that has been getting stuck shut after the ski sits for a bit), cleaned carb, passed a leak down test, new fuel lines and filter, bypassed fuel selector, new check valve.

2nd Ride Issue: After putting it all back together it ran great again until about 30 min. (yes I tried adding gas). It happened the first time i fell off the ski. The engine died because I had the idle set too low. It took a few extra cranks to get it started again and the symptoms I described above began as soon as I got back on the gas... I'm going to pop the carb off again and check that little fuel filter but I'm willing to bet its clean and isn't the problem.


Any advice would be greatly appreciated.
 
Quinc

Quinc

Buy a Superjet
Location
California
San Diego SN said:
The last two times I have hit the water with my single carb, protec built, 61x square, it will run great for 20-30 min then it will suddenly begin to starve for fuel at 3/4 to full throttle.


1st ride Issue: The first time, after it running great for 20-30 min, it bogged down and died during a WOT run which nearly threw me over the bars. After that it ran crappy. It would bog/stall at 3/4 to full throttle, also the idle wasn't strong and it would bog at first with a blip of the throttle. With the choke on I could keep it running so clearly it was running super lean.

What I did to fix it: Fresh mikuni rebuilt kit on carb, brand new needle and seat (that has been getting stuck shut after the ski sits for a bit), cleaned carb, passed a leak down test, new fuel lines and filter, bypassed fuel selector, new check valve.

2nd Ride Issue: After putting it all back together it ran great again until about 30 min. (yes I tried adding gas). It happened the first time i fell off the ski. The engine died because I had the idle set too low. It took a few extra cranks to get it started again and the symptoms I described above began as soon as I got back on the gas... I'm going to pop the carb off again and check that little fuel filter but I'm willing to bet its clean and isn't the problem.


Any advice would be greatly appreciated.
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Next time it happens pull one of your plugs and see if you are getting spark. Also feel your engine/pipe and see how hot it is getting.
 
San Diego SN

San Diego SN

Location
San Diego
Ok thanks for the input.

As far as temp it seems pretty normal. Maybe a lil hot. I can keep my hand on the engine for about 1 or 2 seconds before it gets too hot. Not dual cooled. It doesnt sizzle or steam water when i drip some on it. After the issues begin and i try to figure out wats going on it gets hotter because i believe its running lean.

Ill check for spark but i dont think that the issue. It has fairly new stock electronics and a brand new start stop switch. Also it will fire up and run, just poorly, and will stay running if i use just a bit of throttle or the choke halfway pulled.


Also when i pulled the plugs they were perfect light brown color.
 
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S

SJ 701X

Location
In a hole
If the fuel separator is in there check that. Did you blow the jets out when you rebuilt the carb? Maybe one is clogged. Check the high speed screws and see if there is any corrosion on them. If it happens when you get high in the rpm range it may be an electrical problem too. I had an issue with a ski where it would run okay for 30 minutes bit then it would act weird. Water was getting splashed up into the ebox and was shorting stuff out.
 
San Diego SN

San Diego SN

Location
San Diego
I blew out the jets with compressed air and carb cleaner. Ok ill start going through the electrical system to see what i can eliminate. What was the specific thing that was getting shorted out with yours?
 
S

SJ 701X

Location
In a hole
I honestly can't remember but I had cleaned it out and when I re opened it there was water in it. It didn't seal correctly.

Sent from GS3 Synergy
 
swapmeet

swapmeet

Brotastic
Location
Arlington TX
Exhaust leak.

ride with the hood off, quick and easy test.


Try to fix... ride... works for X amount of time (fills engine bay with exhaust) then dies.

30min is a long time, but its quick and easy to test the exhaust leak theory.
 
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swapmeet

swapmeet

Brotastic
Location
Arlington TX
N3vrSat1sfied said:
or back your trailer into the water and start ski. much easier to see whats going on, as well as safer.
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tumblr_lpedxgKy2Q1qzinus.gif


LOL.....





But seriously, if it takes 30 min of normal riding to create the issue, how long on the trailer?

I dunno... trailer isn't a bad idea I guess.
 
T

taylor2000

Location
Kansas
I fought my blaster for two years. went to higher main jet and it helped. found a pedal in the reed was tore.loh missing manifold and cage gasket too.
 
N3vrSat1sfied

N3vrSat1sfied

Military Member
Location
Fort Worth, TX
swapmeet said:
LOL.....





But seriously, if it takes 30 min of normal riding to create the issue, how long on the trailer?

I dunno... trailer isn't a bad idea I guess.
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Guess I didn't read that part. Maybe ride it for 30 minutes then come in a put it on trailer for diag. Idk I'm just not a fan riding with the hood off, to much at risk.

But if it was an exhaust leak u should see that right away without riding it first.
 
San Diego SN

San Diego SN

Location
San Diego
Its not an exhaust leak because it runs the same way with the hood off. I doubt its crank seals cuz it passed a leak down.

Is there a way to test a stator coil??
 
OCD Solutions

OCD Solutions

Original, Clean and Dependable Solutions
Location
Rentz, GA
You can use a meter to test a stator but the values don't always tell you the whole story. Replacing it with a good known stator is the best way.
 
aytee

aytee

Location
south dakota
run it until it acts up than pop the gas cap off.. if it seems to have a large amount of negative pressure(pulls a bunch of air into the tank) then runs fine again, your tank breather isn't doing its job.. not saying it isn't something else, but it's easy to check...
 
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