Fuel Accelerator Pump/tuning questions for 1998 GSX Limited 951

[blown1993]

I am still doing some fine tuning on my 1998 GSX Limited with the silver 951. I will try and describe the situation I am dealing with.

When I first put the ski in the water, it starts right up by just hitting the start button, no choke, no pull of the throttle. After I run it for awhile I can immediately stop it and it starts right back up by just hitting the start button. If I run it for awhile, shut it off and let it sit for a few minutes or more then it will not start by just hitting the start button, I have to hold the throttle a 1/3 to 1/2 open and it starts right up. All around it seems to be running real well, about 65 on the speedo and about 6900 rpms. So to me, I can see the warm starting issue 2 different ways. 1. The whole system is lean and I am having to get that squirt of fuel by opening the throttle when starting. 2. The system is rich, and I am having to open the throttle to get some more air into the system. 2 complete opposites but I am at the point that I am not sure which one is the cause. The spark plugs are a perfect tan color.

The other thing I have noticed, it seems like the fuel accel pump must be turning off right around the 3600-4000rpm range. If I gradually ease the throttle up to 3600 I can achieve almost any rpm I want. If I try to hold it at about 4000rpm it jumps right up to about 4300-4500 and instantly becomes much stronger and clean sounding/running. So my guess is at the upper 3700rpm range the fuel accel pump stops giving the squirt and the carbs are then doing every thing on their own.

As far as my fuel accel pump questions. I decided to check this thing out and make sure it was set up properly. Does the fuel accel pump adjustment really matter as long as it is giving the squirt? The way it currently is set up is like the manual shows, turn the screw in till it just meets the lever then add a 1/4 turn. By looking at it, it doesnt look like this is correct on mine. At this setting the lever is not fully released when the throttle is closed and it only pushes the plunger a little bit. I tried setting the screw/lever up so that it looks the most square and correct or what looks like to me how it should be, If i turn the screw in about half way then the lever stays fully released and it seems to push the plunger in further when the throttle is pressed. Either way it gives the squirt of fuel, but I think it does it at a different rpm range.

The fuel accel pump shouldnt affect starting at all should it?

I know with the motor off, the fuel accel pump only gives a little squirt of fuel. When the motor is running does it work the same way? or if its in the correct rpm will it continuously squirt fuel?

Either way, if i cruise along in the 2000-3500 range it just seems boggy and rich, but I quickly open the throttle and it doesnt seem loaded up. It doesnt try to die or anything and the plugs come out perfect.

Thanks for your help!

 

[Strizzo]

The accelerator pump only gives a squirt as the throttle is cracked open, this allows you to run a bit leaner on the low speed adjusters to prevent loading up at low speeds. remember to only make adjustments in 1/8 turn increments and ride around a bit to see the effects of the adjustment. If you idle around and bump the throttle a couple times, does it load up then?

 

[blown1993]

I can idle it, crack the throttle open and it doenst sputter at all, so it doesnt seem like it is loaded up. So im guessing the adjustment point of the pump is not too big of deal as long as it gives the squirt.

any guesses of my warm starting issues?

 

[SabrToothSqrl]

Every 951 i've run (about 5 now) have the same issue.

before you hit start, open the throttle once then return it to idle. the fuel pump should make starting easier.

but yea, 90% of the time you need a bit of throttle to start these big 2 strokes.

 

[blown1993]

I also noticed, and Im hoping somebody knows for sure. As for the low speed screw stock setting, the seadoo service manual says 2 turns out, the seadoo specifications manual says 1 1/4. This seems like a big difference and im curious why there is this innaccuracy in their manuals. Other peoples charts I have found online also say 1 1/4. The main service manual says 2 turns out.

 

[SabrToothSqrl]

the '98 was really the first (technically 2nd) year of the 951.

My understanding is the low speed is 1.5 out and the high are 0 for stock 951s.

 

[blown1993]

the 2 different 1998's have different specs per the service manual and the specifications manual. I dont get why they are different!

 

[SabrToothSqrl]

they are really just starting potions, where you make adjustments from. I'd go with whatever manual is dated newer.

Yours appears to be running just fine.

 

[bhatch21]

blown1993, your description of starting a cold engine with no choke and cranking a warm engine by holding the throttle open seems to suggest that it's rich on the pilot, or low speed circuit.

Your experience with the rpm jump and instant acceleration is typical behavior for a Rave equipped Seadoo. The 3 I've own have all done that around the 4000rpm range. I call it the sweetspot. All my 2-stroke quads and bikes, whether equipped with an exhaust valve or not, have a certain rpm where you can feel the stronger pull of the motor come on. Most riders call this "getting into the powerband". Enjoy it.