Carburetor replacement? IH or Zenith?

[Pfranck331]

Bob McCarty & Landreo,
It’s reassuring to know that. 040 is the correct size, guess I should’ve asked that straight out.
Yes seafoam is great , First thing I did when I got it home was put 3 ounces in the oil and .5 pint in the gas tank.
Been running Seafoam in my fleet a vintage motorcycles for years especially in the winter months when they see a little activity.
I think in fact leakage around the float bowl gasket before and after the carburetor repairs as the last of my problems with the carburetor .
I was afraid initially to snug up or tighten that gasket too tight for fear Of warping would return.
This beast is very cold blooded takes a good 20 minutes to warm up before it starts to run nice.
Thinking maybe weak point Spring ....

[Pfranck331]

A couple additional thoughts here,

I purchased one of those new replacement carburetor that Don McCombs reviewed,
In his review he stated the .032" or 0.035" was the correct size for the factory carburetor again my carburetor is .04. This is a contradiction with what Bob McCarty posted that .04" was the correct size, I suspect mine was replaced with a kit intended for use with new aftermarket carbs. So I would ahead Bit the bullet and bought a new one.

The first thing I notice is the choke butterfly rotation operation is contrary to the original rotation. The arm is mounted at such an angle as if you could hook it up to the original existing cable and bracket it would become hopelessly locked in the open position with the choke knob out.

I guess his leaves me with two options, option one not connect to choke cable and stand to the side of the tractor and work the choke, option two try to remove the original choke parts and installing a new carburetor.

Or if anybody else has already solved this problem by dabbing installing a new bracket and cable location, perhaps they could link me to a how to pour maybe somebody could solve this problem and create a how to.

I am somewhat disappointed that this was not mentioned in the aforementioned review.

[Don McCombs]

A. You haven't told us which replacement carburetor that you purchased. The good one from TM Tractor Parts/Steiner or the Chinese eBay junk one for $75 or less. For that matter, you haven't told us the part number of the carburetor that is currently on your LoBoy.
B. Have you tried the repro carburetor on your tractor?
C. The choke mechanisms for the standard Cub/offset LoBoy are different than for the numbered series LoBoys. The choke lever on the standard Cub/LoBoy attaches to the right side of the carburetor looking from the seat. The numbered series attaches to the left side. The choke shafts are entirely different. Both the good and bad repro carburetors are set up to attach to the right side.
D. Neither Bob's nor my evaluations were intended as an exhaustive exercise to determine compatibility in all possible situations. We simply recorded our observations of the two repro carburetors in hand.
E. I have attached a chart showing the original dimensions of most of the orifices in the range of carburetors used on Cubs and LoBoys. This chart does not, of course, account for changes made to the carburetors in the field by replacement or parts swapping by previous owners, i.e. installation of a rebuild kit with the wrong size main metering jet included. Your carburetor should have a part number stamped into the flat spot on the top of the bowl cover. Compare your carburetor with this chart.

IH .75 Carburetor Orifice Sizes.pdf

(86.73 KiB) Downloaded 271 times

[Bob McCarty]

Can you post a picture of the carb with the cable attached?

[Landreo]

The carb reviews were posted on the cub side of the forum and the review may not directly apply to the numbered series. There are several replacement styles available on ebay, some have the hole in the choke lever for the numbered series, some don't, although none may actually be in the correct position. One ebay carb may not be the same as another ebay carb.

I do not care about small differences but it is useful to know if the carb works, i.e. the engine runs, and will common replacement parts fit. Gaskets, float valves, and main jets from the IH carbs may not fit the ebay carbs. You have a ebay carb so it would be helpful to others to do a review since that particular carb may not work well with the numbered series.

GSS-1408, 1978 lists the main jet size as 0.40 inches. All of my IH carbed numbered series have 0.40 inch main jets.

[Pfranck331]

Old, 405004R91.
New Riley Tractor Parts , R4740
Vendor #?251234R92
Box label Made In USA

T&M list there replacement for the 405004R91 as NOT FOR USE with LoBoy 154,
Stiener carb is the one reviewed? Listing says for LowBoy 154 but does not include choke lever, I assume it is like as shown in review and as I pictured

I am curious, if a vendor doesn't have a 90% margin, does that make there product "cheap junk" .

Thanks just for clarification , I now take it that direct replacement for 154 is not available,
I have soldered piece of metal that I folded over ( to clear retaining detent Spring and a new choke lever on top of the existing one in the correct orientation.
I have not installed it yet as the blacktop in front of the shed has heaved after 8 days of high temps below zero.
I have spent the day defrosting the ground an pounding the asphalt down.
It is currently 5 degrees f and promises to get warmer the next few days.

Old carb is leaking gas out of weep hole after installing new float needle seat and gasket, never leaked with old steel needle and seat , new one is style shown in review., also only 2 threads left holding carb to manifold ,, ran well enough to push 13 inches of snow with my modified plow ( plow exceeded my expectations ) bout never ran good a full throttle untill it had worked for over an hour with the grill covered in plastic @ 10f.

I plan to put the old needle and seat and or old gaskets for same back in and to fix the stripped out threads on the manifold mount , I plan to have the original equipment carb back in top shape then I'll lay it aside and use the new one as a working part.



A bit clunky looking for sure, but I do what I can with my limitations.

[Don McCombs]

As the review states, the repro carburetor was from TM Tractor Parts and took place nearly 11 years ago. I believe that the repro carburetor that Steiner now sells is made by the same manufacturer, but was not available from Steiner at the time of the review. My comments on the far less expensive repro carburetors generally available on eBay and other sources, is based on my examination of the carburetor and comparison with the OEM carburetors and the USA assembled repro carburetors sold by TM and Steiner. It is my opinion and I stand by it. Your opinion and results may vary. When you get an opportunity to try your new carburetor on your 154, let us know how it went.

[Bob McCarty]

The carb that I got off of eBay to evaluate is not the same as yours. The eBay version does not have fillister head body screws and also had a thin black paper body gasket. A lot of the eBay ads have them being shipped from China. The manifold studs are 1/4-20 in the carb and 1/4-28 on the end that takes the nut. Easy to helicoil to fix the threads. If your old carb has the correct choke shaft, you can put it on the new carb (unless shaft diameters don't match). Any carb with an .040 main jet should work on a 154 as long as the bleed and discharge tube are correct and the choke shaft is replaced/modified. I don't know of anyone selling the correct choke shaft for the 154 but will see if I can find them.

[Larry B]

http://hamiltonbobs.com/cart/product/ze ... lo-boy-mm4
Not cheap but Hamilton Bob sells a replacement carb
never had a problem with hamiltonbob making things good if there is a problem with a part

[Pfranck331]

http://hamiltonbobs.com/cart/product/zenith-carburetor-p5635/engine-c67/ih-m13/154-cub-lo-boy-mm4
Not cheap but Hamilton Bob sells a replacement carb
never had a problem with hamiltonbob making things good if there is a problem with a part

So you recommend going to a Zenith,
It’s moot now but still hasn’t answered my original questions.
I quote from my original post.
“ ? If so should I use the stock IH carburetor go with a Zenith.
Would staying with the IH carb make this more desirable down the road ?

If I go with a zenith what types of modifications should I be prepared to make ?
Does anybody offer a Zenith that has been set up specifically for the 154?”

By modification I mean : does the fuel line need to be stretched or relocated? does the governor Operating rod fit properly ? Does the choke cable and choke mounting bracket need to be modified to fit the zenith carburetor?

I just finished installing My EBay carb from RTP,
So far so good starts with choke, ran smoother quicker, no gas leaks l know of yet( will check on it after a few hours and it’s cooled down).
My choke lever mod worked even better than stock, lined up better and binds less.

I will say that the manifold flange was one thread lingth thinner than stock an that my longer bolts started to bind as they flushed out with the end, probably wouldn’t keep from torquing the gasket properly but I ran a blind tap though it to clean up the last thread anyway.