SX/SXi/SXi Pro Is it normal to burn a tank of gas in 90 mins?

[RUTDOG]

Hey guys. Just picked up a 93 750sx. The top end is fresh and I was told the carb isnt stock.. I'm having some problems though. It seems to be running rich. The past few times Ive had it out Ive burned a whole tank of fuel in less than 90mins. Is that normal? The ski is a slug and doesnt start running good untill the last half hour of riding then it runs very strong if that makes any sense. The plugs looked fouled the first half of the tank then after I finish the second half the plugs look good.. The oil injection has been removed and I'm running yamalube 50:1. Any ideas please.

 

[ger87410]

Assuming a stock tank, 90 minutes at WOT doesn't sound bad to me. A 580 will burn through a SJ's worth of gas in less then 1 hour, let alone a 750.

Get your ski running right, then go from there. :biggthumpup:

 

[tor*p*do]

sounds a little rich, but my 92 750sx with coffman pipe b
urns almost that much.
if carb was bored, it would burn easily that much

 

[RUTDOG]

I dont know much about these carbs. Last two stroke Ive owned was a 95 YZ250 dirtbike. If it ever ran rich or lean I'd just change the main jet. I have not removed the carb yet on the ski so I dont know much about it. There are a few differnt screws to adjust but I'm not sure which one does what. Should I maybe mix my oil with a differnt ratio then 50:1? Thanks for the replies!!!

 

[RUTDOG]

Heres a pic of my carb. Two adjustment screws on this side, one above the other.

 

[tor*p*do]

that looks like a stock Keihin CDK2 38 carb
top screw is high speed screw
bottom is low
you also have and lo speed jets inside
I would tell you more, but has all been written
just read extensive carb tuning, rebuild, etc
from the articles here: http://www.sbtontheweb.com/techarticles.htm

oh, and WELCOME TO THE X!!!!!!

 

[N3vrSat1sfied]

i go thru about a a half tank in about a hour in the surf.

 

[RUTDOG]

Thanks guys! I'm going out this weekend. Set the low speed from seated -3/4 turn and the high speed -1 &1/4 turn. Ill be taking three five gallon cans with me this time.

 

[RUTDOG]

My ski is running perfect now! After finding nothing wrong with the carb, I did some more looking. The hose between my fill spout and tank was not connected... Gas could splash out and water could splash in. So I guess everytime I filled up I was stirring the water up in the tank causing my ski to run worse after fill-ups?.. And this explains why I was using so much gas. Anyway I rode all weekend with no problems and the ski hauls ass!

 

[OCD Solutions]

My ski is running perfect now! After finding nothing wrong with the carb, I did some more looking. The hose between my fill spout and tank was not connected... Gas could splash out and water could splash in. So I guess everytime I filled up I was stirring the water up in the tank causing my ski to run worse after fill-ups?.. And this explains why I was using so much gas. Anyway I rode all weekend with no problems and the ski hauls ass!

Great troubleshooting, glad to see you got it figured out. It's usually the simple stuff that makes the biggest difference.

 

[jmerkert]

Use double the oil and do not use yamalube ever!!!! I am currently in the process of fixing my 750 that i bought a week ago because it was run with ty oil probably at 50-1. The piston blew 2 holes through my cylinder because it was not well lubricated... "if you run yamalube at 50:1 you may as well not use any oil at all..."- quote from our jetski mechanic

 

[RUTDOG]

Use double the oil and do not use yamalube ever!!!! I am currently in the process of fixing my 750 that i bought a week ago because it was run with ty oil probably at 50-1. The piston blew 2 holes through my cylinder because it was not well lubricated... "if you run yamalube at 50:1 you may as well not use any oil at all..."- quote from our jetski mechanic

Anybody eles have any problems with yamalube? Ive used it my entire motorcross career... My skis plugs look perfect now!

 

[X2Pilot]

I used Yamalube 2-R for many years with zero problems. I was however running it at 40:1.....

I believe that Yamalube is a very good semi synthetic, but I dont buy high dollar oils anymore...

 

[Cliff]

theres nothing wrong with yamalube. may wanna try 40:1

 

[Mile9c1]

I've used Yamalube in many ski's and dirtbikes, no problem. I probably wouldn't use it in a Seadoo though.

 

[Cliff]

definately not in a seadoo