1975 John deere 600

[hoosierfarm]

Ok, I finally got this posted in the right place, not under the calendar tab. Hey- got a question. I bought a really nice shape JD 600 last season. Had new crank seals put in it, and rebuilt the original bendix carb. I rode it a couple times last season (not much snow in Indiana last year). I was really disappointed with the carb performance. THe old 440 had power but you had to play with the throttle a lot to get performance out of the snowmobile. I remember reading on here last year how those bendix carb's aren't anyones favorite, I was wondering if there is any replacement that works well? Is there any that bolt on without much modification? Thanks

[400brian]

According to my parts book, model 600 serial number 30001- should have a Walbro WDA 32.

I could be wrong, but I'm thinking the Bendix and the Walbro interchange no problem. The only thing that comes to mind is the fuel pickup fitting. The Bendix just needs a supply line, while the Walbo requires a return line as well, so different fitting at the tank.

[Matt]

You would also need the choke/throttle cable bracket with the Walbro. There are NOS ones floating around if you check ebay. That's probably the easiest swap.

You can also do a Mikuni conversion, but you would also need a Mikuni fuel pump, throttle and choke cables, a flange mount, and need to modify the throttle hand grip, because the original won't allow full travel of the slide valve. Then you need to test & tune with the jets.

[hoosierfarm]

Ok, whats the easiest /best for the money conversion? To me simple is king, but how is the performance of the walbro? Can I get a new one of those or are they ebay/ swap meet items?

[Matt]

In my opinion, Walbro is the easiest. You would need to watch ebay/swaps/classifieds for a WDA32. Then get a fuel pump gasket kit, and clean the heck out of the carb and rebuild.

[400brian]

What Matt said.

[hoosierfarm]

Ok, I assume the rebuild kits are easy to find. I am still confused about the fuel pump and gasket part? help me out. right now there is a small thin rectangular box near the carb, I assume it is some kind of fuel pump?

[400brian]

Yes, the bendix carb uses a separate fuel pump, with a single line from the tank.
A Walbro has an internal pump, a supply and a return line. The rebuild kits for the Walbro are essentially diaphragms and gaskets.

[hoosierfarm]

ok make sense, so you would take the old pump and line off and discard it? THen run new lines? for the walbro?

[400brian]

Well, I never throw anything away! The square pump isn't valuable, but could be rebuilt and used down the road on something else.

Always put on new line, it's not expensive, and gets brittle after a few years.

You will need a new or used double line bung to screw into your fuel tank ( unless it already has one ).

[JDT]

In my opnion there is nothing wrong with the Bendix design or performance.
Only issue is there are no parts available.

I have had a couple apart, cleaned and reassembled to find them working great.
A couple of others that had so much internal corrosion and damage that they went in the trash.

And I do recall there being a double bung on some of those sleds I had worked on.
As Brian mentioned you will need a double for conversion to a Walbro.

And again there is nothing wrong with a Walbro either. Just need more patience and luck when working on them.

[hoosierfarm]

In my opnion there is nothing wrong with the Bendix design or performance.
Only issue is there are no parts available.

I have had a couple apart, cleaned and reassembled to find them working great.
A couple of others that had so much internal corrosion and damage that they went in the trash.

And I do recall there being a double bung on some of those sleds I had worked on.
As Brian mentioned you will need a double for conversion to a Walbro.

And again there is nothing wrong with a Walbro either. Just need more patience and luck when working on them.

I had a friend who is a snowmobile enthusiast go through my 600 last year. He totally cleaned and rebuilt my carb. ran new fuel lines. Checked the needle and seat, it was fine. I found a new rebuild kit online for the bendix last year, it was basically a gasket and a couple seals if I remember right. When I rode it it would idle and everything fine, but when I got into a little deeper snow, like 6" it seemed to have no power. For a 440 it just seemed really weak. like it wasn't getting enough fuel when I gave it more throttle?? I don't know if that fuel pump should be replaced/rebuilt? Is that the nature of the 600 bendix that they are sensititve to throttle etc? All I do is ride it around out farm, but I am used to a 79 300 twin Yamaha and it seemed to be peppy and virtually problem free on its carb. THis is my first deere so maybe I am just learning slow. Like I said I didn't have enough snow in northern Indiana last year to really ride and adjust it. Only a couple of days.

[JDT]

The fuel pump could be a problem yes.

What else have you done to service the engine besides the carb?

There are a whole list of things that can cause the symptoms you mentioned.

[hoosierfarm]

He went through it for me.

New crank seals. Checked spark plug wires. New plugs of course. New ends on plug wires. That's mainly it on the engine. A few other things were serviced on the sled but not engine work.

[JDT]

Well there are many things to consider.

Is the drive train loose? If you lift up the back of the sled can you spin the track easily by hand? Do you have some bad bearings on the boggies, idlers or drivers?

What is the condition of your clutches? Are the bushings rusty and sticky? Is the spring weak and it is trying to shift up too soon?

Is your exhaust particaly plugged up restricting flow? This will not let the engine breath correctly.

Is your chain rusty and does not run easy around the sprockets? What about the bearings on the top shaft?

What is the compression on the cylinders? If it is low it will start and idle but not develope full power.

What about the intake tube or air box? Is it blocking full air flow?

What do your plugs look like after a short run? Dark, black, wet, dirty? Could be running too rich.

Did you put on a new fuel filter? Tanks that have sat a few years can plug up a filter real fast.

Is your drive belt in good condition and the correct size? If it sits to low on the secondary sheaves it will adversly affect gearing.

What is your gas to oil ration? If it is too high your fuel will not burn hot enough and not produce power like it should.

Oh yeah, your fuel pump may be weak.