• This site contains eBay affiliate links for which Sea-Doo Forum may be compensated.

96 Sportster "lack of power" and rough running issue 717

Status
Not open for further replies.
C

carl1269

New Member
Can any help diagnose this "lack of power" and rough running issue? This is a 96 sportster with a 717 engine here is a link to the audio file. This is the 3rd engine, 3rd set of carbs. we were mired with a "neutral safety" switch that was limiting the revs, but it has been bypassed. This engine starts instantly every time, and idles well, it will barely plane with one person in the boat, and feels like it wants to go, but is starving for fuel. we have changed all the lines, filters, and cleaned everything, the screws on the carbs are set @0 and 1 1/4 respectively (no the screws are not set backwards) all the fuses in the MPEM are good, there are no restrictions on the movement of the linkage (carbs are opening all the way). If I had to put a number on it, i would say the engine is @ 70% power WOT cold. after 15- 20 min, that seems to drop to about 60% power WOT. If I have posted this in the wrong place, please let me know as i am new here.
Thanks
Carl
[video=youtube;vuRoAuADpkE]http://www.youtube.com/watch?v=vuRoAuADpkE&feature=youtu.be[/video]
 
The volume of fuel traveling through the line doesn't seem to be an issue. I had a squeeze ball from an outboard on there, and while traveling under a load, could squeeze the ball, and not feel any effect on the motor. I have changed the ball to an inline filter, which is visibly full of fuel, which looks pristine.
 
It sounds like it's needing fuel. If you cehck the fuel valve like doc said I would open are the carb/carbs and take a look. Might have a clogged fuel filter or that inside.
 
I have 3 sets of carbs, the engine seems to run the same on all of them. I am pulling the internal filter, and i have shot carb cleaner through all the jets, and openings in the carbs. I also bought 2 new spark plugs. I will try again tomorrow. I agree with the starving for fuel, I just cant come up with a reason. i would think that it would run better or worse on different carbs, but it seems to be the same no matter. I will try the aforementioned "cleaning" and test in the water tomorrow. I just don't think it is the fuel valve because when i had the squeezer ball on there, i would pump it while running on a plane, and there would be no change in the engine RPM's
 
on multiple engines? This engine, although bought used, has never been apart, unless the person who did it was an artist. The factory paint is still on the pieces of gasket that stick out, and the screws and bolts look untouched. On the first engine we thought it was the rotary valve, I re-set it. it was a tooth off, and it was still running the same. POORLY
BTW thanks to everyone for chiming in here, sooner or later we are going to resolve this!
 
Sorry, I misread something...lol. Ya, I would probably play the lottery if you had timing issues on three separate engines. lol
 
On that boat you should have a fuel excelerator pump. It's located about 8 inches off your motor strait up. They have a small check valve in there that will go bad and not allow good performance at high rpms. I would check that. Open it up and look for a diaphram. A black flat rubber looking sheet. Hold it up to a light and see if you have any pin size holes in it, if so replace.
 
do you have an external or internal fuel pump? If you have the externa pump could it be going.
 
This unit is set up with meccunie carbs. As I understand it, the only fuel pump is the diaphragm on the carb. We found a plug wire that just slid out of the boot when changing the carbs. we will fix and re-test this afternoon.
 
Yea but I'm pretty sure you have a fuel pump excelerator. These carbs need it to help the flow of fuel at high speeds.
 
I don't see the accelerator pump on your setup. You have the same carb setup as the standard jets ski's. If you had a accelator pump you would have another dash pot on the side of the carb with a small fuel line run to the top of the carb. It's on the some of the other jet boats. I have them also with the external pump on mine. If you found a bad plug wire I am sure after to fix it you will be good since you tried other fuel repairs.
 
SUCCESS!! I DON'T KNOW IF IT WAS THE Plug wire/boot, the last cleaning of the carbs, or the new spark plugs, but after countless hours of belaboring this we have a working boat! Thanks to all for all your feedback!
 
As a matter of fact, in salt water, no tide, wind from the side, 38.5 MPH with 1 200 lb man, and 1/2 tank fuel, no gear
 
Status
Not open for further replies.

Similar threads

J
Engine bogs down above half throttle 1997 Sportster
Replies
5
Views
363
jwill19028
J
winn
1997 Seadoo Sportster Rough Idle/sputtering and dies when i open throttle.
Replies
4
Views
425
burtshaver2021
burtshaver2021
Ed Clark
BN CARB FUEL PUMP EXPERIMENT - Point of Interest Only
Replies
7
Views
100
Ed Clark
Ed Clark
T
92 SP rough running extended idle
Replies
3
Views
248
tomski
tomski
9
2005 GTX 215 no power and runs rough
Replies
6
Views
335
Milehighguy303
M
Back
Top