What can this be?? Motor dying at wide open throttle

W

Woody

Need to save my money!!
Location
Long Island
When riding wide open throttle...after about 10 seconds, the motor just shuts off...not getting enough fuel with 140 sized jets (apparently 1 bigger that what it should be). I'm running a stock 701sj with b-pipe, ada head and msd enhancer.

when we opened the jet all the way up...it seemed to be working fine...unfortunately for me it was after i stuck a piston.

why is this happening?? im want to ride my ski no wrench it!! is something wrong with the fuel system??? what should i be checking out?
 
ADDict

ADDict

There are a ton of things that can restrict fuel flow like that.. Sounds like a lean seizure. I did the same thing to my new 701 a couple weeks ago, my high speed jet was too low. Not saying thats your problem, but I was running a 152.5. 62t/61x ported with a b-pipe/head/msd enhancer/single carb.
 
W

Woody

Need to save my money!!
Location
Long Island
The Penguin said:
I recently had a similar issue (it sounds like) - the internal fuel filter (inside the carb) was full of sand.
Click to expand...

ryan my mechanic also said we should check the filter....

mxkris said:
I had the same type of issue, but i wan running out of air in the hood. My hood tubes where shoved to far up into the aftermarket hood.
Click to expand...

now you've got me thinking...cause i have my 3 front hood holes plugged with little 1/4" dia holes to replace them. i haven't seen the hood being sucked in at all...but now you've got me thinkin bout it. if this is the case though...why when we opened the jets up it wasn't giving me the problem anymore??
 
The Penguin

The Penguin

triple secret probation
Location
down by the river
I've got all the front holes glassed over on my hood. If your ski runs better with the hood off - that might indicate that it was an air starvation issue.
 
junkyardj

junkyardj

┌∩┐(◣_◢)┌∩┐
Location
barrie ont. canada
the air sounds like a good idea but it wouldent explain the seized piston.. like uk said check all you fuel filters first including the ones in the carb, check to see your return is pumping and your 1 way valve is working..
 
OCD Solutions

OCD Solutions

Original, Clean and Dependable Solutions
Location
Rentz, GA
I can add a 3rd scenario. One of my skis was doing this last year and it was pi$$ing me off trying to track it down. It would run perfect at every throttle position for an unlimited amount of time, if I opened it up and did any full throttle runs then it would just cut out and die after about a 10 second run. It would fire right back up though and run perfect again. It was repeatable every time.

When I went to pull my carbs I found a split fuel line just before the restrictor jet on my tank return line. At full throttle I am calibrated to have 5 psi and it was spraying a fine mist of fuel until it was too rich to run. I trimmed the line back and it has run perfect ever since.

Doesn't explain the seizure but who says they have to be related.
 
junkyardj

junkyardj

┌∩┐(◣_◢)┌∩┐
Location
barrie ont. canada
Boykid88 said:
I can add a 3rd scenario. One of my skis was doing this last year and it was pi$$ing me off trying to track it down. It would run perfect at every throttle position for an unlimited amount of time, if I opened it up and did any full throttle runs then it would just cut out and die after about a 10 second run. It would fire right back up though and run perfect again. It was repeatable every time.

When I went to pull my carbs I found a split fuel line just before the restrictor jet on my tank return line. At full throttle I am calibrated to have 5 psi and it was spraying a fine mist of fuel until it was too rich to run. I trimmed the line back and it has run perfect ever since.

Doesn't explain the seizure but who says they have to be related.
Click to expand...


good call check your lines too
 
W

Woody

Need to save my money!!
Location
Long Island
may i add...the tips of the plugs were white....vs. the "golden brown"...too lean on fuel with wide open 140s?? Something in the fuel line or should i increase the jet size?
 
OCD Solutions

OCD Solutions

Original, Clean and Dependable Solutions
Location
Rentz, GA
Maybe we should back up a bit here. Have there been any recent mods/repairs/buildups or are we troubleshooting a ski that has run perfect in the past and now doesn't?

Are you still dialing in jetting for a new configuration or setup?
 
O

oldone1

Kawgirl's ski had a bad fuel switch, removed fuel switch and replaced it with only fuel lines and everything is great. So fuel lines and the fuel switch.
 
YAMA CAT

YAMA CAT

Catnip Junkie!
Location
B'ham, AL
Checked your timing? If your plate has been advanced as well having a Enhancer. You may have too much timing, causing you to deto on WOT.
 
W

Woody

Need to save my money!!
Location
Long Island
Boykid88 said:
Maybe we should back up a bit here. Have there been any recent mods/repairs/buildups or are we troubleshooting a ski that has run perfect in the past and now doesn't?

Are you still dialing in jetting for a new configuration or setup?
Click to expand...

new build...the mods have been an ada girdle head, b-pipe, msd enhancer and a lightened stock flywheel.

cmeripper26 said:
Definately running way lean. What are your high speed adjustment screws set at?
Click to expand...

wide open...

YAMA CAT said:
Checked your timing? If your plate has been advanced as well having a Enhancer. You may have too much timing, causing you to deto on WOT.
Click to expand...

haven't touched the timing...
 
You must log in or register to reply here.
Top Bottom