Improving the 140 pump

[SexPanther]

Best ways to improve performance with a 140mm pump. Does cleaning up the rough casting areas make much of a difference? Just saw a pretty wild tbm pump cone for sale, anyone know if those things are worth while? Is it worth just stepping to the mag pump? I’ve never had a ski with more veins in the pump. Not sure I’ve even been aboard one.

 

[kevbo]

A large hub impeller pitched properly will provide most of the gain. A 12 vane stator will help a little more, especially with bigger engines. Start with the impeller, it will work well with the stock pump.

 

[SexPanther]

A large hub impeller pitched properly will provide most of the gain. A 12 vane stator will help a little more, especially with bigger engines. Start with the impeller, it will work well with the stock pump.

Running a Hooker pitched for application by Impros. Also using a wet wolf stubby pump cone. And a 650 sx turn nozzle.

 

[fastgtfairlane]

The pump stuffer will.have the opposite affect of the stubby cone. The stubby cone loosens the pump up allowing the engine to spin up quicker. The pump stuffer adds more load to the engine. It's a tuning tool. It will create better hookup in choppy water. More efficient. Like a mag pump. The stuffer makes the stock pump like a large hub mag pump without the extra stator veins.

 

[Big Kahuna]

See if you can find the R&D pump plugs, this really helped with my SXR. You could also fill the void with silicone. I was never a fan of the TBM Pump Cones, but I was running stock class.

 

[user_error]

Definitely get a pump stuffer, either TBM or R&D. They are nearly identical but work great for the price if a magnum pump is out of reach.

 

[Quinc]

I sent Glen an email at impros and he said if you already have the hooker impeller the pump stuffer gains will be minimal.

For my 650 pump I sharpened the exit side of the pump veins and cleaned up the rough casting marks. Would probably help to smooth out the entire pump but who has that kind of time.. Biggest benefit came when I switched from a skat 15/18 to a hooker 10/16; picked up bottom end and top speed.



Hooker on left Skat on right

 

[Quinc]

And old post I found from @john zigler on 650 pump alignment.

Correct / proper way to align a KAW Floating driveline (any with rubber hull shaft carrier bearing);

Install jet pump.

Install bearing carrier to hull, with 100% silicone, but do NOT tighten yet.....

Set engine in, and center. Install engine bolts to engine mounts, and tighten.

Now - go back and tighten the drive bearing carrier to the bulkhead.

To be honest this should be done anytime you remove the pump, OR engine for proper alignment. This will reducing any binding, bearing stress, and spline wear., and ensures proper engine/shaft/pump alignment.

 

[SexPanther]

And old post I found from @john zigler on 650 pump alignment.

This is great to know. Tons of awesome information here! Thanks guys!

 

[kevbo]

For racing, 80mm nozzles seem to hold high speed a little better than larger ones do. A stock 650 or one of those 84mm aftermarket nozzles will provide noticeably better acceleration with minimal rpm rise.

 

[Quinc]

Anyone know the nozzle sizes for different kawa pumps? like x2, ss, sx, sc, etc? I think the jetmate is 90mm.

 

[kevbo]

I know that 750-800s have 76-80mm metal nozzles, they are the same casting so the smaller one can be bored. Plastic 650sx nozzles are 82. X2s had plastic nozzles and there are an early and late style, havn't measured those. I always lost acceleration whenever I tried a 750 nozzle, regardless of the impeller.

 

[SexPanther]

What about the inserts that you silicone into your pump tunnel? It looks like pro watercraft makes one. I have a 140 pump on a 550 tunnel, would this be a good mod for me to try? Or would it exaggerate the small pump tunnel issue?

 

[fastgtfairlane]

What are you trying to accomplish? I personally think the weak point is the hull. The 550 pump tunnel is way too small for a 140mm pump and a 701. I rode a 550 for 8 years and tried just about everything except for a 140mm pump and could never get it to hookup especially in choppy water which is basically all I ride in. Going to a superjet alone greatly improved my riding ability. 550s are good for learning to ride standups and that really is about it or a good clean vintage collector that rarely sees water.

 

[SexPanther]

What are you trying to accomplish? I personally think the weak point is the hull. The 550 pump tunnel is way too small for a 140mm pump and a 701. I rode a 550 for 8 years and tried just about everything except for a 140mm pump and could never get it to hookup especially in choppy water which is basically all I ride in. Going to a superjet alone greatly improved my riding ability. 550s are good for learning to ride standups and that really is about it or a good clean vintage collector that rarely sees water.

I’m just trying to maximize performance using reasonable mods. I live in the mountains of Idaho and am used to riding Washington Surf. I went to a 550 for the challenge on flat lakes and rivers and because they are the raddest jetskis ever made, the OG.

The goal is really reliable balanced performance. The ski already absolutely rips for a JS. I would even argue there is no intake tract size problem, when I compare thrust out of the hole to fast 550 setups I have been on. Now I’m just trying to tinker with it and see what works well and where I can gain performance.

 

[kevbo]

Oh its a JS hull. I would make the inlet longer with a large radius.

 

[fastgtfairlane]

I'm sure on glassy water it's a ripper but start adding chop snd and that's where the longer, larger pump tunnel will come into play. The larger tunnel with a good pump setup will help keep the pump in the water in the chop. I did all kinds of work to mine from hull truing, glassing in deeper strakes, 3 inch wider tray, footholds, shorter pole, pump tunnel fill, removing the caps at the back of the ski. And still couldn't get the hull to stay in the water with some chop and it made it more difficult to try anything off any kind of a wake. With the superjet it's soo much easier and get much higher off a wake.

 

[Quinc]

@SexPanther have you made anymore changes or tried anything new? Also did you notice any difference with the stubby cone?

 

[Quinc]

@SexPanther have you made anymore changes or tried anything new? Also did you notice any difference with the stubby cone?

^^^