[Mark8589]

Hey Folks ,

I have an 89 Polaris Sprint that I have owned for the last 2 years. At the end of each season I'd drain the tank and let the machine run until it ran out of gas. So far that has worked. However the start of this year the machine would start however not stay running at idle. If I try to keep it running using the throttle it would eventually die. I pulled the carbs and cleaned them following the great carb cleaning write ups in this forum. Set the pilot air screw to 1 turn out. I also replaced the fuel lines while I had the carbs off.

I still have the same behavior as before cleaning the carbs. I can get the machine started using full choke however after turning the choke off the machine will not stay running. I pulled the plugs and they are wet , so I assume it is not a fuel issue. I tested the plugs and they have good spark.

I double checked everything using the write ups here and can not find out what is going on.

Any idea's ?

Mark

 

[kccats]

Did you push a piece of stranded wire threw the pilot jet? And spray threw the the passages?

 

[Mark8589]

Yep , I ran a wire through all of the passages (pilot jet , main jet etc.) along with carb cleaner and then blew out everything with air. Filled the bowls with a syringe into the fuel port

 

[Old Man]

Is the plunger stuck in the enrichment circuit? It's quite possible that if it's stuck, even after you move the lever to the off position that it is still allowing more fuel into the mix. As your sled warms up it will start to flood and stall.

 

[Mark8589]

Just checked the plungers and both are moving freely and not binding. Looks like that the plungers are in and then are pulled up with the lever is moved either to mid or full ? Is this the expected behavior ?

 

[RJ Gleason]

Idle rpm?
Should be 1800-2000 rpm.

 

[Mark8589]

RJ ,

Not able to get the machine to run long enough to determine idle RPM. Basically I need full coke to get it started. Without it , the machine acts like it wants to fire and keep going however never does. One I get it started with full choke (usually 1 to 2 pulls) I shut off the choke and the machine runs for about 5 seconds and then stalls , however acts like it is trying to stay running. Cleaned carbs , ran wire through all openings , blow out with air and reassembled. Filled bowls through fuel intake to limit having to pull forever to fill the bowls. Changesd all fuel lines while I had the carbs off. I know it is getting fuel as when checking the plugs the are wet with fuel. I though it might be the floats however when I had the carbs apart I did not notice anything wrong with their function. These carbs do not have any vent lines, just 1 fuel line running to each from the fuel pump.

 

[RJ Gleason]

How is the fuel flow from the pump?
It should spurt from the lines (1/4 to 1/2 inch) when the engine is pulled over.

 

[Mark8589]

Checking the pump was my next place to start. What is the best way to check this ? Take the fuel lines off the carbs and catch the fuel in a container while pulling the engine over ?

 

[RJ Gleason]

Exactly.

 

[Mark8589]

RJ ,

Quick fuel pump question ? This machine (89 Polaris Sprint) is a 340CC dual carb (30MM). The fuel pump is square and has 1 input , 1 pulse and 2 outputs (one for each carb) however all the rebuild kits and new pumps for that matter indicate that the square pumps only have 1 output ? Does the pulse line need to be a certain type of line ? I remember reading somewhere that you could not use reg fuel line here. Not sure when it was replace last and want to replace everything while I was in there.

Mark

 

[RJ Gleason]

Best to use reinforced (high pressure) fuel line for the pulse line as it can not collapse on the vacuum stroke.

 

[Mark8589]

Ok , well I got the machine running today ! Appears that I missed cleaning a couple of the holes in the pilot jet(s) on both carbs. This was my first time cleaning carbs so did not know how many holes to look for I got the idle correct however very boggy on take off under weight. Checked for a cracked boot all was Ok. Checked by spraying carb cleaner on the boots and PTO seal no change in RPM. Pilot screws are about 1.2 out from lightly seated. Sled idles great however under load / weight it does not want to go. While I had the carbs off to re-clean the pilot jets again I checked both the main jet and the needle / seat and all were clear. Any idea on the bogging ?

 

[Mark8589]

Update : Appears that if I put the choke on half while under way performance goes way up. So does this mean I still have a carb issue (one of the other jets maybe) or fuel pump ?

 

[RJ Gleason]

Yep, still the pilot jet.