Super Jet Bah Baaaaah Bogging

drlguy

drlguy

Location
MA, USA
I have a 94 SJ I bought in pieces and put back together 2 weeks ago.

It rips (no bogging whatsoever) for about 2 minutes from a cold startup or until the motor heats up. I adjusted the lowspeed setting and it cleaned up slightly but still bogs pretty bad no matter what the setting(runs best at about 1 - 1/2 turns out but still nowhere close to how it runs cold) It always runs very strong mid and top. It has a riva redpipe. The carb is a single 44mm with a 135main, thats all I know so far.


I've fixed a small exhaust leak between the manifold and expansion chamber I thought was choking the motor out after the engine compartment filled up with exhaust but that didn't help any... I also rebuilt the carb and that didn't help either.

Any ideas?

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drlguy

drlguy

Location
MA, USA
It happens in the water.

Stock 61x
Riva Redpipe and intake
135 main
115 pilot
1.5 n&s
Silver spring... looks shiny (65grams)


I think I may be onto something though. This weekend I discovered that the idle adjustment was almost completely seated on the spring. I have messed with the low speed setting in the past and it runs best at 1 1/2 turns out but then it idles poorly... Dug a little deeper and discovered it had the STOCK pilot and n&s.

Going to buy a 140 and 145 main, 120 and 125 pilot and a 2.3 n&s with a 95 gram and try some different settings.

I am still unsure why it runs so great out of the hole cold for a few minutes... mid and top always hit hard.
 
Legdrag's

Legdrag's

X-
Location
West Palm Beach
So when you first put in the water its great? What if you ride it until it start bogging on the bottom again. Dry the exhaust out. take it to the shore & blow it out. Then stick it in the water right away? try that to see what happens.

2.0 n&s, 80 gram with a 120 pilot & 135 is OK but you can go higher.
 
drlguy

drlguy

Location
MA, USA
Usually the ski sits anchored in the water during the day and then I pull it from the water overnight. I will try drying it out.

Also going to remove the temp sensor from the head to see if that does anything.
 
drlguy

drlguy

Location
MA, USA
Changing the pilot jet didn't help and I pulled it out of the water and dried the pipe out. That didn't help either.

THEN I pulled the hood off and rode it around. NO BOGGING! I looked for an exhaust leak again but found nothing... The pipe gets very hot to the point that a drop of water will sizzle on it.

What can I try next?

Open up the hood vents?

Should the Riva Redpipe sizzle when hot?
 
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Al//gsx//sj

Al//gsx//sj

Location
Lafayette,La.
what prop you running? i found out that too tall of a prop may load the pipe making it feel like it's bogging and have no bottom end snap (speculation at this point since i haven't changed the prop on my ski yet to confirm it.) i know my pipe gets very hot, but not sizzles.
 
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drlguy

drlguy

Location
MA, USA
skithis said:
With the red pipe make sure that the little water hole is clear underneith the top coolant fitting.
Click to expand...

That was it! You were exactly right... I took the top 90 fitting and the small hole was completely clogged. Cleaned it out and it now hits hard all day! The pipe was heating up way to much and it was choking out my bottom end power. I can hold my hand on the pipe for almost 5 seconds now without burning!

That's very much Skithis and everyone else for the great input.
 
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