300/440/550 1989 JS550 Problems...

H

HammerheadDrums

Location
Colorado Springs, CO
I have a stock 1989 JS550 with the only mod being a K&N air filter. I cannot get it to start unless I use fluid directly into the carb. When I get it running, it bogs down in the water and dies. When it is out of the water, it will start up with no problems.

Any idea as to what I should start checking. I am going to check the compression tonight, and order a carb primer kit tomorrow.

I ride at 5500 ft elevation.

I did a search and really could not find anything, so if this has been covered, SORRY!

Thanks!
 
Wave Chaser

Wave Chaser

Location
League City, TX
Carb problems/adj. It dies in the water because its under load. The low speed adjustment or screw is clogged or needs adjusting or maybe just the carb itself needs to be cleaned out.
 
ger87410

ger87410

How did I get here?
Location
Fort Worth
The seller may have said the carb was rebuilt without saying WHEN it was rebuilt... It may not need a rebuilding, just a cleaning.
 
Tyler Zane

Tyler Zane

Open Your Eyes
Location
Panama City Beach, FL
ger87410 said:
The seller may have said the carb was rebuilt without saying WHEN it was rebuilt... It may not need a rebuilding, just a cleaning.
Click to expand...

true, but its not that expensive to do it. i like to do it so i know that its done right and when it was done last. its an old ski. and it probably would not hurt to get it done right for his elevation.... just my .02
 
mxd253

mxd253

MXD253
Location
EAST TN
Just had the same problem when I bought an '87 a few weeks ago. I'm pretty sure that it will be the same carb that is on mine. Mikuni Standard BN series (not Super BN). Six screw pump cover. What I'm assuming happens even within a years time is this F*#king Ethanol they are feeding us and calling it Gasoline is killing the clear plastic diaphrams. (they look bubbled up when carb is apart). If that is the carb that is on yours, hit up a local Parts Unlimited dealer and order #MKBN3844. Now this carb has not jets. It opperates off of a High Speed adjuster screw and a Low Speed screw. The rebuild kit has a nice exploded view of each part and shows which screw is which. My suggestion is run them both in all the way and take it to the water. Nose it up to the dock with the hood off and open the low speed 5/8 of a turn out and the high 1 turn out, that should get it to start. From there run that biotch WFO and make 1/8 turns until you get it dialed in. You being at 5500 ft there is no way for me to tell you exact turns out on them so keep playing with it. I had my hood off prob 5-6 times before she was dialed in. Good Luck
 
Mr Bojangles

Mr Bojangles

Lord of the Dance
Location
Brevard County, Fl
Well I can tell you I tried all that you said for my 44bn and after 4 hours I gave up. Turns out that, yes the screws are the onlything you can adjust, but if you have modded the motor you need more fuel and you need to play with the needle to let more in. So I gave up and just bought a sbn, you don't need to tear the whole carb apart to work on it
 
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