Bad bottom end bog ? ET967

[Motoman947]

So I am running a ET 967 with a total loss system, and I have a bad low end bog. Like there is no low end snap. The least amount of throttle you can give it (like when setting up a wake) it sounds as if its running on one cylinder. Once you get into the throttle more its runs normal, this is just at low end cruising speed. Plugs are a nice golden brown, I'm just not sure where to start here weather its fuel, spark, tuning or something else. I have checked the reeds and carbs.

I'm new to this ski and jet skiing in general, I come from dirt bikes and snowmobiles so its a little different. Any input is appreciated to help me figure it out. Thank you.

 

[Freakie]

Might be lean off idle....check pop-off pressure for both carbs...also that n/s are not leaking on either carb. and pilot sizes as a start imo.

 

[DAG]

What jetting starting points and TL curve has your engine builder provided?

 

[Quinc]

Also start the ski with the hood off and make sure you do not have an exhaust leak.

 

[TheBuzzard]

turn the low speed carb screws out 1 turn more and see if it gets better. you can always just screw them back in if it does nothing and that'll tell you if its fuel related or not. you could screw them in too incase its loaded up on the bottom

 

[Motoman947]

Might be lean off idle....check pop-off pressure for both carbs...also that n/s are not leaking on either carb. and pilot sizes as a start imo.

Thanks. I will test the pop off pressures and needle and seat. As for jets it has 135/140 mains and 130 pilots

 

[Motoman947]

What jetting starting points and TL curve has your engine builder provided?

135/140 mains and 130 pilots. I am not sure on the TL curve. I bought the ski used last fall

 

[newbee]

Just wondering on what size carbs?
Thanks

 

[Motoman947]

Il

Just wondering on what size carbs?
Thanks

Ill have to double check but 48mm I believe

 

[newbee]

Full Spectrum?
46s run 125 p 130 mains 18 to 20 psi pop off
That's what I was told for 46 but no tl

 

[Motoman947]

I suppose what i need to do is get new plugs and ride around 1/4 throttle and check the plugs to see where im at. What is a good starting position for the high and low speed screws ?

Thanks

 

[newbee]

Was the ski ever okay? I mean you bought it running so is this a probably that just started?

 

[Motoman947]

Was the ski ever okay? I mean you bought it running so is this a probably that just started?

This is just an issue ive been dealing with so far this season

 

[newbee]

Okay so it's shouldn't be getting ect being it ran well before. Let us know what carbs you are running if you would.

 

[jaxrider]

did you ask Art? im runnning dual 46 125/130 18pop.

 

[jaxrider]

one of the guys in our group had a bad bog issue with his 48s. I know he likes his 46s much better.

 

[Motoman947]

Okay so pop off pressure is 17-18 on both. My only game plan right now is to get new plugs and ride it around 1/8 - 1/4 throttle for a bit and see where im at with a plug check. So we'll see on the weekend!

 

[Robbie8984]

Plug chops are really only accurate when you are riding the ski hard or as close to WOT as possible.

On the 1200 I’ll go and do as many flips as I can in a row, kill gas quick and check plugs.

The bottom end you tune by feel. As said you need to determine if it’s lean or rich.

If you give it a good few hard blips on the throttle and it runs clean it’s rich if it dies when you hit the gas it’s lean.

Rich turn bottom screws in, lean turn out.

I’d try that and see where you are.

 

[Robbie8984]

Also old plug are best for checking plug colour. On a new set it takes a while to get enough carbon on them to be able to read.

 

[newbee]

Have you had the chance to test it out again?