Need Help With VM34 Carb on '96 Z 440 - Snowmobile Forum: Your #1 Snowmobile Forum

jimmyv13 · 01-13-2008, 09:48 PM

I dove into the Z 440 this weekend hoping to figure out why it starts so hard when cold. I had to pump the fuel 4 or 5 times to get it to fire with the choke on full. It usually started on the 2nd or 3rd pull, but I shouldn't have to pump the flipper that many times to get it to fire. Anyway, I pulled the carbs and found the clutch side carb had a frozen primer in the closed position which doesn't allow for any fuel to get in when the choke lever is flipped. I am unable to free the primer, it's in there for life...the choke lever moved because part of the lever part that conneced both cables to the lever was broken inside allowing one carb to get primed, but not the other. I've been scouring the net looking for a used carb for this machine and have come up empty so far. My question is, will any VM34 Mikuni housing or body work as long as it is set up for a primer system and not a choke? The rest of the existing carb is in perfect condition, so all I really need it the housing and I can swap over the jets, etc.

Any info would be greatly appreciated. I put the sled back together and it starts and runs just like it used to(by pumping the fuel), but I'd much rather have it starting like it's supposed to.

Thanks...

IRONDOG · 01-14-2008, 12:27 AM

Quote:

Originally Posted by jimmyv13

I dove into the Z 440 this weekend hoping to figure out why it starts so hard when cold. I had to pump the fuel 4 or 5 times to get it to fire with the choke on full. It usually started on the 2nd or 3rd pull, but I shouldn't have to pump the flipper that many times to get it to fire. Anyway, I pulled the carbs and found the clutch side carb had a frozen primer in the closed position which doesn't allow for any fuel to get in when the choke lever is flipped. I am unable to free the primer, it's in there for life...the choke lever moved because part of the lever part that conneced both cables to the lever was broken inside allowing one carb to get primed, but not the other. I've been scouring the net looking for a used carb for this machine and have come up empty so far. My question is, will any VM34 Mikuni housing or body work as long as it is set up for a primer system and not a choke? The rest of the existing carb is in perfect condition, so all I really need it the housing and I can swap over the jets, etc.

Any info would be greatly appreciated. I put the sled back together and it starts and runs just like it used to(by pumping the fuel), but I'd much rather have it starting like it's supposed to.

Thanks...

"Pumping the flipper" does not assist starting in any way- it does not pump fuel into the engine when you thumb the throttle, there is no accellerator pump on the carb in question. Now that we've got that out of the way, the stuck choke plunger needs to come out. The best method is drilling and tapping the plunger for a bolt that is threaded into it and using a slide hammer to remove the plunger. You can only drill so deep into the plunger or you risk damaging the seat area of the carb body that the plunger rests on. This is not a method recommended for beginners, as one slip and the carb is toast. I can do it if you want to ship the carb up here near Flint or stop by on your way up north. I am just off I-75.
Jerry

**smallengineguy** · 01-14-2008, 07:07 AM

Like Irondog said, drill the plunger (it's brass) and remove it. I've done quite a few, quite easy. Let it soak in penetrant first. Pulling the choke flipper up opens the choke circuit, dropping the flipper closes it, no pumping required.

jimmyv13 · 01-14-2008, 09:16 AM

Thank you fellas for the replies.

Why does it start when I pump the flipper before I pull? If I don't touch it, I'll be pulling all day and it won't start. If I don't pump the flipper and give it half throttle it'll start after 6 or 7 pulls on a cold start. There is no rhyme or reason with this sled....on warm starts, after sitting for about an hour, it's a PITA to start. Nothing that I do works every time to get it started. I've started it by holding 1/2 throttle no choke a few times, sometimes I have to hold it wide open no choke, sometimes 1/2 choke and 1/2 throttle, sometimes full choke and 1/2 throttle...sometimes it takes 1-2 pulls and sometimes it takes 20. If the motor is hot, stopped for a few minutes up to about 30 minutes, it usually starts on one pull, no throttle.

I am seriously considering drilling out the brass plunger. I have a drill press and could probably do it. I spent most of my Saturday messing with it trying to get it out, I left it soaking in PB Blaster on the bench.

I want to fix this thing and get rid of it. My wife doesn't really like riding it, she'd rather ride the Doo and I'm riding a friends REV right now, so the Cat is really not needed in my fleet except as a rental.