Super Jet SJ 650 no start

Axel85 · Nov 30, 2018

Situation:
1990 650 Superjet had zero spark:
-replaced the coil

-checked starter, inside of ebox had zero corrosion.

-Reinstalled exhaust and ebox. Ski will crank and has spark. Check fuel, ski is also getting fuel.

-sprayed starting fluid and ski still wouldn’t fire. (Has to be Air right?)

-checked compression, front and rear are at 125psi. (Low enough to cause a no start?)

-pulled intake and carb and checked reeds, all intact, obviously not stiff as stock but they are not broken either. Clean reeds and reinstall... ski will crank but won’t fire.

To me it would have to be an air:fuel mixture at this point. Do I rebuild the carb? Do I rebuild the top end? Can an exhaust leak cause a no start situation?

Thanks.

SuperJet-Dave · Nov 30, 2018

Doing all the right things. A carb rebuild seems like the right next step. Fairly easy to do.
125psi is definitely low. So even if you get it started, you will need to figure that out. Could be a leak in a gasket or oring depends on what head you have. I assume you checked that all head bolts are tight already.
Could also be plug wires or boots if you did not replace them when you replaced the coil. (If you have a weak spark)
Doubt an exhaust leak could cause a no start problem.

MarkWalker · Nov 30, 2018

Did you check your start stop switch? www.x-h2o.com/index.php?threads/how-to-fix-your-sj-start-stop-switch.135834/

Axel85 · Nov 30, 2018

SuperJet-Dave said:
Doing all the right things. A carb rebuild seems like the right next step. Fairly easy to do.
125psi is definitely low. So even if you get it started, you will need to figure that out. Could be a leak in a gasket or oring depends on what head you have. I assume you checked that all head bolts are tight already.
Could also be plug wires or boots if you did not replace them when you replaced the coil. (If you have a weak spark)
Doubt an exhaust leak could cause a no start problem.

Ski is completely stock and has never been worked on. It’s not my ski just figured it would be an easy fix for a friend. Haha.

I bought a used coil with boots and plug wires from JM.

I will start with the carb rebuild, the carb does swap fuel onto the top of the butterfly after its done turning over. The carb had obviously been opened up. (Mis matched screws)

Thanks for the reply.

Axel85 · Nov 30, 2018

MarkWalker said:
Did you check your start stop switch? www.x-h2o.com/index.php?threads/how-to-fix-your-sj-start-stop-switch.135834/

Ski has spark now but that’s definitely some solid info to have instead of jumping to replacing a coil pack.

Thanks

MarkWalker · Nov 30, 2018

Is it acting like it wants to start while cranking it?

Axel85 · Nov 30, 2018

It puttered a few times, but now it just cranks.

MarkWalker · Nov 30, 2018

Axel85 said:
It puttered a few times, but now it just cranks.

How old is the fuel? Did the ski sit for a long time?

Axel85 · Nov 30, 2018

No info on the fuel.

Ski won’t fire with starting fluid, that’s why I’m assuming it’s an air leak.

TheBuzzard · Dec 1, 2018

put new spark plugs in it. I just had a no start condition where I had the plugs out, saw spark, but it wouldn't fire. I thought no way was it the plugs, but as soon as I put some used Toyota pickup plugs in there it fired right up. after I ran it for a minute, I tried to put the non starting plugs back in. no start. just cause you see the plugs sparking doesn't mean they are good

Axel85 · Dec 1, 2018

TheBuzzard said:
put new spark plugs in it. I just had a no start condition where I had the plugs out, saw spark, but it wouldn't fire. I thought no way was it the plugs, but as soon as I put some used Toyota pickup plugs in there it fired right up. after I ran it for a minute, I tried to put the non starting plugs back in. no start. just cause you see the plugs sparking doesn't mean they are good

Put new plugs in, plugs are dry and it still won’t start with starting fluid.

Next step will be new reeds and a carb rebuild.

SuperJet-Dave · Dec 1, 2018

Another simple thing to check is the pulse line. Tight on both ends? Worn/hard/stiff?

Axel85 · Dec 1, 2018

SuperJet-Dave said:
Another simple thing to check is the pulse line. Tight on both ends? Worn/hard/stiff?

I will replace it, my thought was since I can see fuel being pulled into the carb the pulse line was good.

Thanks

TheBuzzard · Dec 1, 2018

new reeds and a carb rebuild aint got nothing to do with it not firing. I've started motors with no carb on there just by squirting gas in the hole. if the reeds were bad, gas spits back out the carb top. that's how you know reeds are bad. don't use starting fluid. just dump gas down the carb. the plugs shouldn't be dry. enough gas in the motor and it not running will show wet plugs.

Axel85 · Dec 1, 2018

TheBuzzard said:
new reeds and a carb rebuild aint got nothing to do with it not firing. I've started motors with no carb on there just by squirting gas in the hole. if the reeds were bad, gas spits back out the carb top. that's how you know reeds are bad. don't use starting fluid. just dump gas down the carb. the plugs shouldn't be dry. enough gas in the motor and it not running will show wet plugs.

I’m pretty sure it’s the carb and the reeds. I’m also assuming the air pilot is clogged at this point. After letting it sit for a day there is fuel on top of the Intake leaking from the carb base.

Axel85 · Dec 2, 2018

Thanks for all the input and help. I ended finding the problem.

Issue number 1) start/stop switch lanyard electrical contacts needed a solid cleanings.

Issue number 2) stop wires where they connect to the ebox leads were severely corroded and I’m sure this was the reason why the start/stop switch needed to be rebuilt.

Thanks for the help!