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Discussion Starter · #1 ·
Here is an update on my Polaris magnum 425 4x4.
I cleaned the old carb as much as I can. Could not access the bowl because 1 screw would not loosen and was stripping while trying. I had bought a new fuel pump. Hooked everything up. No matter what I did, it would not start. The carburator had heavy varnish and was stuck before I cleaned it. So I said, "forget it".
I purchased a new OEM carburator. Adjusted the fuel/air screw to 2 turns out. Still won't start. Fuel is getting to the carberator. I did replace all fuel lines with new ones. The motor sounds like it wants more gas. Then I found out a BIG ISSUE.

WHO ENGINEERED THIS CARBURATOR WHERE THE FUEL/AIR SCREW (that you are suppose to adjust when the engine is warm) IS LOCATED UNDERNEATH, ON THE ENGINE SIDE, IN A HOLE???? THERE IS ONLY 2" CLEARANCE BETWEEN THAT AND THE HOT ENGINE.

Sorry for the yelling, but very frustrated. They took something that is very easy and then they tried to make it impossible.

Well this old man used some Texas ingenuity and made 2 tools to use. I took 2 long gutter nails, flattened and shaped the ends as a flat head screw driver. Then I bent the ends of both. Since there is only a 2" clearance and only enough room to turn the screw 1/4" at a time the ends of each nail are 90° in opposition. Attached is a picture of my hand made tools. It's night time and time to call it quits. I will try to use these tomorrow. Let you know how it goes.

This Texan is tired.
151305
 

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Discussion Starter · #2 ·
Here is an update on my Polaris magnum 425 4x4.
I cleaned the old carb as much as I can. Could not access the bowl because 1 screw would not loosen and was stripping while trying. I had bought a new fuel pump. Hooked everything up. No matter what I did, it would not start. The carburator had heavy varnish and was stuck before I cleaned it. So I said, "forget it".
I purchased a new OEM carburator. Adjusted the fuel/air screw to 2 turns out. Still won't start. Fuel is getting to the carberator. I did replace all fuel lines with new ones. The motor sounds like it wants more gas. Then I found out a BIG ISSUE.

WHO ENGINEERED THIS CARBURATOR WHERE THE FUEL/AIR SCREW (that you are suppose to adjust when the engine is warm) IS LOCATED UNDERNEATH, ON THE ENGINE SIDE, IN A HOLE???? THERE IS ONLY 2" CLEARANCE BETWEEN THAT AND THE HOT ENGINE.

Sorry for the yelling, but very frustrated. They took something that is very easy and then they tried to make it impossible.

Well this old man used some Texas ingenuity and made 2 tools to use. I took 2 long gutter nails, flattened and shaped the ends as a flat head screw driver. Then I bent the ends of both. Since there is only a 2" clearance and only enough room to turn the screw 1/4" at a time the ends of each nail are 90° in opposition. Attached is a picture of my hand made tools. It's night time and time to call it quits. I will try to use these tomorrow. Let you know how it goes.

This Texan is tired.
View attachment 151305

Another update....

While trying to start, choke on, fuel/air screw at 2.5 turns out, the engine acts like it wants to start, but every now and then there would be a backfire in the exhaust pipe..

Any thoughts?
 

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Another update....

While trying to start, choke on, fuel/air screw at 2.5 turns out, the engine acts like it wants to start, but every now and then there would be a backfire in the exhaust pipe..

Any thoughts?
Spark plug is bad or you have a late spark.
 

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You were extremely lucky to find a new OEM carb - they have been discontinued for over 20 years.

I would be very interested in obtaining the old carb for parts and will pay the shipping to get it

BTW, the fuel screw is positioned where it is partly due to the US Government/EPA requiring it be inaccessible for the average vehicle operator to prevent unnecessary air pollution. Here's the tool used by the professional mechanic to make field adjustments, however field (shop) adjustments are only possible after the bronze or aluminum cap has been removed to gain access. I have seen new generation carbs with tamper proof screws that have the adjustment head broken off the screw and then the screw secured with adhesive to prevent adjustment and/or removal. The powers that be have determined carburetors should not be cleaned or serviced, but should be replaced. When the engine reaches 5 years old, it is to be scrapped and replaced with a newer more efficient version. Now in the next 10 years all gasoline engine powered vehicles will be phased out and replaced with electric powered units. Gasoline will no longer be manufactured by 2035 and all coal, natural gas and oil harvesting will cease. Anyway, that's a problem I will not face, it will be dealt with by my grand children who my daughter is raising to have some common sense and accept their racism for what it is.

OH YEAH - almost forgot the pic of the special tool
151314
 

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1995 magnum 425 4x4 2019 sportsman 570 2020 sportsman 850
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Sounds to me like the run switch is off or partly off. I know because my 95 has acted the exact same way and the run switch was off.
 

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Discussion Starter · #7 ·
You were extremely lucky to find a new OEM carb - they have been discontinued for over 20 years.

I would be very interested in obtaining the old carb for parts and will pay the shipping to get it

BTW, the fuel screw is positioned where it is partly due to the US Government/EPA requiring it be inaccessible for the average vehicle operator to prevent unnecessary air pollution. Here's the tool used by the professional mechanic to make field adjustments, however field (shop) adjustments are only possible after the bronze or aluminum cap has been removed to gain access. I have seen new generation carbs with tamper proof screws that have the adjustment head broken off the screw and then the screw secured with adhesive to prevent adjustment and/or removal. The powers that be have determined carburetors should not be cleaned or serviced, but should be replaced. When the engine reaches 5 years old, it is to be scrapped and replaced with a newer more efficient version. Now in the next 10 years all gasoline engine powered vehicles will be phased out and replaced with electric powered units. Gasoline will no longer be manufactured by 2035 and all coal, natural gas and oil harvesting will cease. Anyway, that's a problem I will not face, it will be dealt with by my grand children who my daughter is raising to have some common sense and accept their racism for what it is.

OH YEAH - almost forgot the pic of the special tool
View attachment 151314

It was easy to find an OEM carburator for my Polaris. It isn't a Mikuni (like the old one), but it looks just like it. It came with 1' of fuel line, 4 clamps, air filter, and all of the hardware for the carburator. It even came with an extra brass choke connector (one attached to the carberator and extra one in a bag). It just cost $40+. I ordered it on Amazon Friday morning and got it in the mailbox on Saturday. QUICK.

The old Mikuni carberator had no disc covering that screw. Neither did the new OEM carburator.

Those nails I fashioned to adjust the air/fuel screw, worked, but was cumbersome. Then I got another Texas bright idea. I fashioned a small key that you can place on the screw hole and turn easily. I made it out of 1/4" copper pipe and a thin piece of mild steel shaped as a "T" with a tapered end as a "flat-head screwdriver. I cut a slot across the end of the pipe piece and hammered the steel in place.

IT WORKS GREAT!

Here are 2 pics of the new tool I made.

20210503_212223.jpg


20210503_212303.jpg
 

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Discussion Starter · #8 ·
Sounds to me like the run switch is off or partly off. I know because my 95 has acted the exact same way and the run switch was off.

If the run switch was slightly off, would I still be getting a good spark on my plug? My new sparkplug is getting great spark.
 

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It was easy to find an OEM carburator for my Polaris. It isn't a Mikuni (like the old one), but it looks just like it. It came with 1' of fuel line, 4 clamps, air filter, and all of the hardware for the carburator. It even came with an extra brass choke connector (one attached to the carberator and extra one in a bag). It just cost $40+. I ordered it on Amazon Friday morning and got it in the mailbox on Saturday. QUICK.

The old Mikuni carberator had no disc covering that screw. Neither did the new OEM carburator.
I would still be interested in obtaining the old Mikuni carb for parts.
 

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Discussion Starter · #11 ·
I would still be interested in obtaining the old Mikuni carb for parts.

Not a problem. If you pay for shipping and send me an address I will send it to you. Just a reminder, it is very dirty and tarnished. I soaked it in gasoline, used carb cleaner, and got the "gate valve" (or that sliding mechanism that goes up and down) unstuck and cleaned up much as possible. The rubber diaphragm is intact. I couldn't access the bowl because one screw would not come out.

Also, do you have a copy of any manuals on a Polaris magnum 4x4 that you wouldn't mind sharing?
 

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Not a problem. If you pay for shipping and send me an address I will send it to you. Just a reminder, it is very dirty and tarnished. I soaked it in gasoline, used carb cleaner, and got the "gate valve" (or that sliding mechanism that goes up and down) unstuck and cleaned up much as possible. The rubber diaphragm is intact. I couldn't access the bowl because one screw would not come out.

Also, do you have a copy of any manuals on a Polaris magnum 4x4 that you wouldn't mind sharing?
Sending you a private message
 
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