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1947 farmall cub- how do i get more hp

Posted: Sun Nov 11, 2012 1:14 am
by ad356
as you might know my cub is a 1947, which i believe puts her at a mere 9hp. i know this engine came in 9, 15, and 18 hp. i know that the 185 lo-boy had the most modifications of all cubs to develop more power. what is the difference specifically between my 1947 and a 154? can i safetly turn up the rpms a little without hurting the engine or wearing it out faster? i know the list of modifications IH completed on the C60 in its production run included different carburetor and different pistons. can i install a zenith carburetor on my cub without changing anything else or would it just run too rich? my engine does not smoke and runs decent but it loads down quite a bit while starting out from a dead stop on even a fairly small hill. is that normal for this engine. i just seems a little underpowered and i plan on running a 60" belly mower next spring. is it at least going to do a fairly good job in modestly tall grass or is she just going to struggle. the tractor does push like a little bull when in 1st and 2nd gears, i just wanted to know the easiest way to add a couple HP, im not expecting a 25-30hp tractor i just would like to be able to get a few more ponies out of her. also how do i know if this engine is a 9 or a 12, i think they offered 9, 12, 15, and 18 in a C60??

where do i get a fairly cheap tach for testing purposes so i know im not going wild with any possible governor adjustments i might make? tractor has the magneto style ignition.

Re: 1947 farmall cub- how do i get more hp

Posted: Sun Nov 11, 2012 1:53 am
by Yogie
I think a good tune up with a valve adjusting is about the best you can do with it. You might run a compression test after that to see what numbers you come up with and if it needs a rebuild.
The later model engines had several changes to bring up the HP. Dome pistons and the Zenith carb you spoke of plus a different cam, lighter govenor weights for higher RPM's and a larger manifold for the faster air flow in and out.

60 inch mower is more like a lawn cutter and will work a good running cub. You might do better with something like a Woods 42 with the swing type blades. Others, who know more will talk more about mowers in the morning.

Re: 1947 farmall cub- how do i get more hp

Posted: Sun Nov 11, 2012 3:38 am
by cub47
Keep in mind the HP rating on an early cub like you have is rated at the drawbar-----the engine HP is actually higher.

I agree with Yogie in that if you perform a complete tuneup and do the necessary engine checks, you will see an improvement in performance.

Here is a device similar to what I use to check engine RPM's. You use it at the end of the PTO shaft center:

http://www.ebay.com/itm/Hand-Held-Tacho ... 60&vxp=mtr

In regards to mowing, besides a good tuneup to your cub, the adjustment of the mower deck helps performance also---make sure the back of the mower deck is a little higher than the front.

Re: 1947 farmall cub- how do i get more hp

Posted: Sun Nov 11, 2012 8:26 am
by Boss Hog
The 184s had the most HP, you 47 will need to be in tip top condition to cut with a 59 in mower.

Boss

Re: 1947 farmall cub- how do i get more hp

Posted: Sun Nov 11, 2012 8:47 am
by Bus Driver
Increasing the engine speed will risk overspeeding the mower unless the driving pulley is changed to a smaller size. And that might involve using a shorter belt.
Except for putting your tractor through a dynamometer test, no one knows if speeding the engine will boost the power. Chances are that it will not boost peak horsepower. Increasing the speed alone will not boost peak torque- and torque is what does the work. Horsepower is a measure of how much work the torque does.
As a case in point, some years ago I frequently drove two buses (not at the same moment obviously) that were identical except that one had the governor set at 2600 RPM, from the factory, and the other had been set for 2800 RPM, a modification done by person unknown. The higher speed engine would propel the bus faster on level and downhill. But up steeper hills, both traveled at the same speed. The torque peaks remained the same.
Within the significant limitations of the 1947 Cub engine speed, a little more torque could be achieved by higher compression with domed pistons. Changing the camshaft might shift the torque peak to a higher RPM, with resulting greater torque, but only at higher engine speed. Keep the ignition system in top condition.

Re: 1947 farmall cub- how do i get more hp

Posted: Sun Nov 11, 2012 10:06 am
by Former Member
Your best bet for more power is to get a Long stripe cub. You will never regret it. :big afro:

Re: 1947 farmall cub- how do i get more hp

Posted: Sun Nov 11, 2012 10:14 am
by Eugene
My cub is a 1947, which i believe puts her at a mere 9hp.
That particular engine puts out about 13 HP at the flywheel during factory dynamometer tests and 9 HP at the draw bar. Peak engine torque is 1600 RPMs. Peak torque on the higher HP rated engines is just about the same.
i just wanted to know the easiest way to add a couple HP.
Easiest and cheapest, consider buying a bigger tractor. Seriously, prices on used tractors and implements appear to be lower than several years ago due to the economy. The cost of up grading your engine components to gain a couple engine HP will put you in the price range of a bigger tractor with more features.

Re: 1947 farmall cub- how do i get more hp

Posted: Sun Nov 11, 2012 10:57 am
by lazyuniondriver
Bus Driver wrote:...and the other had been set for 2800 RPM, a modification done by person unknown.


He he he... Imagine that!

Your description of speed to horsepower clearly demonstrates that overspeeding the engine at no load has no effect on horsepower under load.

If you were beating a dripping green engine up those steeper hills, the 71 series torque peaked out at only 1400 rpm, the reason for crawling up those steep grades smoking away.


As far as getting a 60" mower started, the extra rpm will get it into motion faster, perhaps without bogging or stalling the engine but as soon as grade meets high grass, first gear won't be low enough unless the engine is in tip top shape.

I have one older cub dedicated to mowing equipped with a Woods 59. The engine is in good condition and in perfect tune. High grass on uphill slopes sometimes has to be cut a little higher or on the downhill run. 60" mowers may disappoint you if not kept on the flat and level.

Re: 1947 farmall cub- how do i get more hp

Posted: Sun Nov 11, 2012 12:13 pm
by ad356
my lawn is mostly flat with small hills in a couple areas. no steep hills on my property. as far as getting a newer tractor, well then it wouldnt be a cub wouldnt it? i like the cubs, i like the way the are built and the simplicity of the tractor. so if i rebuilt my engine in the future if i went with domed pistons, a different cam, and a zenith carburetor i could build more power, but as it sits there is not much i can do beyond making sure she's in top running condition, which i believe it is. i checked the cap and rotor and its fairly new. i pulled a couple of plugs, normal deposits no sign of oil burning. i did notice that she has a little more power when fully warmed up. when i bought my cub i was considering a farmall "A" but they are no hydraulic lift, that leaves me with a "super A", but they are typically selling for more money. i do prefer the older farmalls to something newer. i think they are neat collector items and they still have quite a bit of utility built into them; not as capable as something newer but still capable

Re: 1947 farmall cub- how do i get more hp

Posted: Sun Nov 11, 2012 12:32 pm
by lazyuniondriver
In keeping the cub culture alive with what you have now, consider a tow behind mower with its own gas engine if your cub proves to be underpowered spinning a sixty inch deck.

Re: 1947 farmall cub- how do i get more hp

Posted: Sun Nov 11, 2012 5:00 pm
by v w
Consider getting an A and use it for mowing and the cub for everything else. $$$$$ Of course I don't have an A and common sense tells me I don't need an A but I sure would like one. A super A probably is best for mowing. A few more $$$$$ Hydraulics. Vern

Re: 1947 farmall cub- how do i get more hp

Posted: Sun Nov 11, 2012 6:48 pm
by Rudi
ad356 wrote:where do i get a fairly cheap tach for testing purposes so i know im not going wild with any possible governor adjustments i might make? tractor has the magneto style ignition.


The link Brian gave you is for a Stewart Warner style tachometer but at $144.00 that is really expensive. I just searched :eBay: for Stewart-Warner 757-W Tachometers and just about died from shock :shock: :?

Image

These ones are cheaper :

Stewart Warner Hand held mechanical Tach Tachometer

VINTAGE STEWART WARNER HAND HELD TACHOMETER-4000 RPMS

Machinists NEW Perfect Stewart Warner Tachometer

Either folks think they are made of gold or the prices have really skyrocketed. I bought mine for around $20.00 and for a long time the average price was about that. I would suggest watching :eBay: for a while and wait until you can get one for much what would be in your budget. They are highly valued as they are no longer made if I understand correctly.

You need to do a tune-up on your Cub, check that the governor is working properly, valve lash is set properly and you have good plugs - Champion D-21's are about perfect. My '47 has as my buddy Dave says - lots of grunt and Granny is surprisingly strong. Ellie my '48 does the lions share of work around here and she does a whole lot of work, and the 9 drawbar HP is more than enough to handle all that I ask of her. Maintenance is key ... it really is.

Re: 1947 farmall cub- how do i get more hp

Posted: Sun Nov 11, 2012 7:22 pm
by ntrenn
Not sure of the exact configuration they built in 1947, but having had both a Woods 42 and a Woods 59 underneath my '63, for normal grass mowing, they pull just about as hard. I wish I had found a 59 years ago as it's great for wide open spaces as long as you don't let the grass get too tall. Fantastic for leaves too...

As far as more power - yes you can convert to some of the newer parts. Yes you can turn up the governor to 1800 FLGS with 2000 RPM no load. It will give you some Revs for it to pull down through before you get to peak torque and it will be more driveable. You will use more fuel.

If you have to pull the engine down, consider the upgrade, but best is like others said - get your tune right on - valves, timing, plugs, air cleaner - it really is more like a 15 hp tractor than a 9 hp tractor when you get everything right.

Re: 1947 farmall cub- how do i get more hp

Posted: Sun Nov 11, 2012 9:06 pm
by Boss Hog
There is no comparison to a 47 cub with stock engine to a late 75 and above International cub as to power if both are in good condition and well tuned , Those that post other wise either have never had a longstripe cub or had one that was out of tune or wore out.
Boss Hog

Re: 1947 farmall cub- how do i get more hp

Posted: Sun Nov 11, 2012 9:42 pm
by Yogie
How can we have or had when you now have them all Boss ? :lol: