1999 Sea Doo GSX 951 went full throttle then stopped

[b12soccer]

Hello,

I had recently changed all the fuel lines on my 99 GSX with the 951 engine. Everything was working just fine before and after the fuel line change. I started it up today and it slowly progressed to go full throttle in a matter of seconds. I shut it off because I was concerned. Now it won’t even start.

My initial thought is maybe the throttle cable doesn’t have any slack, but it does. I tried messing with the fuel selector thinking maybe I had it on reserve, but it still doesn’t start on either selection. I’m thinking maybe there’s an air leak in the carb seals or one of the lines? Engine cranks over still but won’t fire over. Any ideas? Weird it was running fine last week and now I all of a sudden have this issue

 

[b12soccer]

Also, the return line has fuel coming out of it, rave valves are clean and freshly rebuilt. Ski has spark and battery is charged. I've seen some other forums the issue is something with the carbs.

 

[SIMPLEARKANSAN]

I'd rebuild with Back to OEM Mikuni carb rebuild kit from OSDparts.com.

 

[mikidymac]

Either your throttle is not closing all the way, your carbs are not providing enough fuel and you are lean or you have an air leak.

 

[Grim]

Did you change out selector valve or filter? Sounds like you are getting air in the lines. Double check your hose connections since that is what changed.

 

[b12soccer]

Did you change out selector valve or filter? Sounds like you are getting air in the lines. Double check your hose connections since that is what changed.

Yes I bought a brand new selector and filter when I changed out the lines. Everything was running fine until yesterday I wanted to take it out, and this happened. Im seeing this is pretty common with these 951 engines. I've narrowed it down to either something with the throttle cable, possibly the springs, or theres an air leak with the carbs. It cranks but doesnt fire over

 

[Grim]

Yes I bought a brand new selector and filter when I changed out the lines. Everything was running fine until yesterday I wanted to take it out, and this happened. Im seeing this is pretty common with these 951 engines. I've narrowed it down to either something with the throttle cable, possibly the springs, or theres an air leak with the carbs. It cranks but doesnt fire over

What do you mean by everything was running fine, were you on the trailer, on a garden hose or in the water?

One way to see if it is the carbs or the lines going to the carbs, take the gas line going to the carb off and put it in a container of gas/oil mix and run the ski, if it runs well then its between the gas tank and the carb, if it is still running bad it is the carbs (it could also still be the lines too.)

 

[mikidymac]

Idle on a 951 should be set at 2,800 rpm out of the water which will be 1,400 in the water.
Due to 951's being divas anything higher and they can run away even when everything is perfect.

 

[Boyd12]

Remove the spark plugs, put a LITTLE bit of fuel in it and see what happens. It should start and run for a couple seconds and die. I had one that sat for a long time and wouldnt start. Once I did this, it fired right up. I guess there was not enough vacuum to suck the fuel from the tank to the carbs. I also didnt want to burn a starter up for nothing.

 

[b12soccer]

What do you mean by everything was running fine, were you on the trailer, on a garden hose or in the water?

One way to see if it is the carbs or the lines going to the carbs, take the gas line going to the carb off and put it in a container of gas/oil mix and run the ski, if it runs well then its between the gas tank and the carb, if it is still running bad it is the carbs (it could also still be the lines too.)

On the trailer with the hose

 

[b12soccer]

The issue is in the carbs. I will be installing brand new carbs, along with new gaskets. I'll just keep the old carbs as spare parts and maybe rebuild them just have laying around. Clearly these 951's are very sensitive. Since the carbs are off, I'm going to replace the starter just so I have reassurance, heard these have a tendency to go especially since it's the OEM starter.

At least when I'm done with it, everything will be brand new except a top end LOL

 

[mikidymac]

Aftermarket starters are junk.

Just put new brushes in the OEM starter.

 

[b12soccer]

Is this one junk?

Sea Doo 947 951 Starter Motor GTX GSX XP RX LRV DI Ltd 278000987 278001937

 

[mikidymac]

It is aftermarket so you are taking a chance, the are not the same as OEM on the inside.

 

[Crpilawa3]

I had the same thing happen to me last your it ended up being the bendix chipped some teeth also i would check to see if the pick up coil broke off the perch

 

[b12soccer]

Full throttle issue was a carb issue. Ended up getting new carbs and I'll rebuild the other ones for spare parts. Runs like a champ now