1850 carb usx 37 marvel

Can't decide on what to do with it, I've rebuilt it with a kit, but I wasn't thrilled with it. Runs well enough, but not good enough. I get the impression it couldn't handle a load.

Anybody use Dave's rebuild services? He ain't cheap, but the reviews are very good. They rebuild them here for less, but they only talk about basic kits in the rebuild, I thing I need more, things are just wore out more than the kits provide. Anyone used the service here?

Is there a replacement/upgrade carb for this tractor?

You said: I've rebuilt it with a kit, but I wasn't thrilled with it. Runs well enough, but not good enough. I don't know what kit you used but I have never found a kit that had everything I needed. Did you test the carburetor with a vacuum gauge as explained in the Oliver and M-S manuals. If not you wasted your time. Yes there is a replacement Zenith. Remember they bough M-S.

If it still has a Holley distributor in it, I
would look into that before going any further with
the carb.

The USX carburetor was not one of Marvel's better products. In good condition and properly set it works OK. But it's very fussy to keep in good shape.

Particularly critical is the accelerator pump diaphragm. It is generally not included in rebuild kits. And any stiffness, leakage, etc. of the diaphragm renders the carburetor impossible to set correctly.

I managed to order a kit containing the diaphragm for my son's 1850 thru the local JD dealer (same carb is used on the 4020 gasser). It worked OK for a couple years. But now needs attention again. I suspect ethanol now in gasoline has attacked and ruined the diaphragm.

Looking into the zenith carb off the JD 4020, they say they replace the 37 but when I look at the charts the 37 isn't listed. Was there something different about the 37?

They have the Zenith carb here, I contacted them, no word yet.

Till then a local Oliver dealer believe it or not still has the same guy there that sold them way back when, he rebuilt it. Runs better/fine, but even he had reservations. We both thought the float was odd. Most have plenty of room in the bowl, this one almost fills the entire bowl. He wasn't a fan of these carbs either.

Still has the Holey Dist, I removed it, cleaned it up good, replace parts, set points...and reinstaled it. It's only problem is also an odd one. It blows the coil wire out of the cap. All new parts, I zip tied the boot on.

Great tractor, it's getting there. This whole chain thing on the trans bothers me, seems to operate with more vibration then I care for. With the clutch disengaged the tractor is very smooth, let the clutch out engaging the hydraulics, not so smooth. Is it always engaged even sitting idle? I guess it is since it runs the PS. Do these chains stretch? Had a Harley way back when, the chain stretch wasn't noticeable over time, what a difference when I replaced it.

What is the Zenith number to replace the USX37? Is it #15108?

Got a call from YT today after I asked about the
carb on the 4020, the linkage is on the wrong
side. According to the tech here the only option
is to rebuild the 37. The search continues. It
can't be to hard to come up with an alternative
even if that means modifying the intake. I mean in
that day things were simple very unlike today
where computers control everything.

Till then the carb I have is performing and the
new fuel pump from YT came today.

It really does run well, I just don't think it
would pull itself apart if I told it too, not that
I would but I want it there.

(quoted from post at 18:16:11 11/05/14) Got a call from YT today after I asked about the
carb on the 4020, the linkage is on the wrong
side. According to the tech here the only option
is to rebuild the 37. The search continues. It
can't be to hard to come up with an alternative
even if that means modifying the intake. I mean in
that day things were simple very unlike today
where computers control everything.

Till then the carb I have is performing and the
new fuel pump from YT came today.

It really does run well, I just don't think it
would pull itself apart if I told it too, not that
I would but I want it there.

Click to expand...

I bought a new Zenith carb online 3 years ago for a much smaller tractor, and it arrived with the linkage on the wrong side. I was going to send it back but after studying it a bit I found that it was designed for the linkage to be switched. So by carefully removing the throttle shaft and the choke plate I was able to get the linkage on the correct side and it's been running just fine ever since.
So, I think I'd check out that option before giving up on the new carb.

PS What Zenith number did they have for the 37 replacement?

I just looked at some images for the zenith, it's
on the right side. Another reason given was they
hadn't seen a zenith in ovr a year and a half
(didn't have one anyways). I was thinking they
would not make one that wasn't universal if they
were on either side.

Here's one, I just look up carbs for the 4020
http://www.griggslawnandtractor.net/new-zenith-
replacement-carburetor-fits-john-deere-4010-4020

Not saying these guys have one either, I haven't
asked.

I see that 15108, says it works, image is the same.

You have e-mail or a phone number?

(quoted from post at 04:26:37 11/06/14) I see that 15108, says it works, image is the same.

Click to expand...

Maybe this could work:

http://www.thecarburetorstore.com/servlet/Detail?no=7

I saw that one, don't see why not.

Haven't had much luck with just about everybody
except for a local guy when it comes to parts for
this tractor (makes me question this carb). Most
say they have the right parts, they don't. The
fuel pump from YT was wrong and it turns out was
for the diesel engine which they didn't know and
still don't as far as I know. Cost me return
shipping and they had no clue what lift pump is
needed so I had to trudge on.

The local guy pulled the right fuel/lift pump the
first time and knew exactly the difference between
the gas and diesel parts. Cost was little more
than double, but it is what it is, I don't mind.
Live and learn. He has no zenith carb for this
tractor.

(quoted from post at 04:35:49 11/06/14) You have e-mail or a phone number?

Click to expand...

Yes, do you have an e-mail or phone number? There's a good chance I'll be in the same boat come March, so I'd like to contact you and see what your experience has been, especially if you go the route of a new carb.

I'm in the same boat,the Zenith replacement they sent me for my oliver 1600had to have everything switched over to the other side of the carb. this USX seems to have provisions for the same thing. mine will start and idle fine but as soon as you start to throttle up it bogs down and dies. You can hear it starts sucking air then that dies. It also seems to leak fuel if left more than 30 minutes like the bowl fills up and overflows.I also ran into the same problem with the fuel pump although I called and talked to a tech and we figured out that it was for diesel and he couldn't find anything for the gas, although this tractor has had the fuel pump bypassed and runs off of gravity feed fuel line. Granted that probably wouldn't work under heavy loads but really the only thing this is used for is brush hogging. I also noticed the same issue with almost no travel in the float that somebody else mentioned earlier.

I've used these guys before. Jim is good to deal with.

http://www.farmersserviceinc.com/carbrebuild.htm